Abstract:
Because access to travel time information can significantly influence the decision making of both agencies and travelers, accurate and reliable travel time information is increasingly needed.One important step in providing that information is to identify the sensors best suited to provide travel time data for a given corridor. Currently, few studies have evaluated the effectiveness of various travel time data collection technologies side-by-side. This evaluation was intended to provide decision support for transportation agencies looking to select travel time systems on the basis of accuracy, reliability, and cost. This study focused on two test corridors: State Route 522 (SR 522) (an urban arterial with frequent intersections) between the NE 153rd Street and 83rd Place NE intersections, and I-90 (rural freeway built over Snoqualmie Pass in the Cascade mountains) from milepost 109 (Ellensburg, Wash.) to milepost 32 (North Bend, Wash). The sensor systems tested were Washington State Department of Transportation’s pre-existing automatic license plate reader (ALPR) system, Sensys emplacements, the TrafficCast BlueTOAD system, Blip Systems BlipTrack sensors, and a third-party feed from Inrix. This study’s approach was to look at the Mean Absolute Deviation (MAD) to judge the expected magnitude of error, then examine the Mean Percent Error (MPE) to find ant systematic biases in the data. The Mean Absolute Percent Error (MAPE) was useful for finding the relative magnitude of the error, and the Root Mean Square Error (RMSE) was used to determine whether a few large errors or many smaller errors were occurring. Each system in the analysis demonstrated different strengths and weaknesses that should be considered in addition to its accuracy and sample rates. Some systems can provide additional data; others trade accuracy and coverage for cost or portability. Ultimately, engineers will need to weigh their requirements for accuracy and sample rates against the other engineering constraints imposed on their system.

Authors:
Cheng, T., Malinovskiy, A.Y., Corey, J., Namaki, B., Wang, Y.

Keywords:
accident rates

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Abstract:
The mission of the Washington State Department of Transportation (WSDOT) is to keep people and business moving by operating and improving the state’s transportation systems vital to our taxpayers and co mmunities. Traditionally, the Department has focused its efforts on the transportation systems. However, a growing portfolio of transportation assets is burdening an old and often outdated portfolio of building assets that support WSDOT core mission and ho use employees, who design, construct, maintain, and operate state highways. The capacity and condition of these building assets are critical ly challenged by the failure of various building systems, which, when they happen, can be very disruptive or even ha zardous to WSDOT daily operations. Considering the long overdue preservation and replacement of these assets, there is an urgent need to (1) understand how the asset performance influences the various functions that support the Department’s core mission, ( 2) identify the impact of alternative funding levels upon building asset performance, and (3) prioritize the Department’s fundin g decisions in order to fulfill its core mission through a safe and sustainable working environment. This research project is th e first step in a series of potential research projects designed to develop an in - depth understanding of building asset management processes, challenges, and opportunities for WSDOT. This project is an exploratory case study focusing on the Vehicle Repair Shop in the Northwest Region Maintenance Facility in South Seattle. This shop was built in 1954 and is located in a site complex with 33 separate structures, totaling 114,025 SF of space that houses staff and equipment for the maintenance and operation of state highways. The analysis outcomes show that failures occurring at the TEF shop can significantly affect its ability to service the department’s vehicles and equipment. Given the importance of some of these vehicle and equipment in operating the state’s transportation system, failures at the TEF shop can also significantly affect WSDOT's ability to fulfill its mission.

Authors:
El-Anwar, O., Migliaccio, G., Lin, K-Y, Gatti, U., Medina, Y.

Keywords:
accident rates

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Abstract:
The report assesses the usefulness and effectiveness of safety and public service announcement (PSA) messages through surveys conducted in four urban areas in t he United States: Chicago, IL; Houston, TX; Orlando, FL; and Philadelphia, PA. The surveys were designed to specifically address the types of safety and PSA messages for each respective city. A total of 2 , 088 survey responses were received and analyzed . Th e report further captures findings and recommendations based on the analysis of the survey responses.

Authors:
Boyle, L., Cordahi, G., Grabenstein, K., Madi, M., Miller, E., Silberman, P.

Keywords:
accident rates

Abstract:
The combined Washington State Department of Transportation (WSDOT) traffic sensor data and third party data are huge in volume and are highly valuable for system operations, monitoring, and analysis. The current WSDOT traffic data archive systems, however, lack the capability to integrate third party datasets and are not offering the functions needed for real-time performance monitoring, quick operational decision support, and system-wide analysis. The goal of this study was to remove the barriers in the current datasets archived by WSDOT, automate the time- consuming data quality control process, and achieve the integration and visualization of information needed to support decision making. The research findings are not only summarized in this report but are also delivered in a functioning online system named WSDOT Digital Roadway Interactive Vi sualization and Evaluation Ne twork (DRIVE Net). This WSDOT DRIVE Net system is capable of collecting, archiv ing, and quality checking traffic sensor data from all WSDOT regions and incorporating third party data, such as those from INRIX, Inc., and weather information into the analytical platform. Roadway geometric data are properly stored in an open-sourced, geospatial database and are seamlessly connected with the traditional transportation da tasets. The existing WSDOT da ta archiving and analysis systems, CD Analyst and FLOW, are successfully recode d and integrated into the WSDOT DRIVE Net system for better efficiency and consistenc y. A series of loop data quality control algorithms is automated in the backend for detecting malfunction loops and correcting them whenever possible. With the new data platform empowered by eScience transportation principles, two commonly utilized functions at WSDOT have been implemented to demonstr ated the efficiency and utility of this new system. The first is to generate WSDOT’s Gray Notebook statis tics and charts. This new function will allo w WSDOT personnel to produce the tables and figures needed for their annual and quarterly congestion reports in seconds , a significant effi ciency improvement over the months previously necessary. The other function is the Level of Service (LOS) map for highway performance assessment. This module follows the Highway Capacity Manual (HCM) 2010 procedure to produce the LOS estimate for each roadway segment every 20 seconds based on real-tim e traffic measurements. Additionally, a mobile sensing data analysis module was developed as a pilot experiment for reconstructing pedestrian trajectories using the Media Access Control addresses captured from mobile devices. Traffic engineers and researchers can directly access the WSDOT DRIVE Net system through the Internet. The system has demonstrated its ability to support more compli cated analytical and decision procedures for large-scale transportation networks.

Authors:
Wang,Y., Ma,X., Malinovskiy,Y., Corey,J., Henrickson,K.

Keywords:
accident rates

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Abstract:
Land development that is not coordinated with transportation planning can compromise the performance of Washington's state routes.  Identifying land at risk for development along state routes can provide opportunities for proactive, collaborative planning to improve access, mobility, and safety while supporting economic development.  This project, described in two parts, provides tools to help turn adverse risks of land development into opportunities to make route improvements.      In part one, systems for identifying land at risk for development were developed for the state and local levels from relevant literature and expert input.   Risk factors for land development at the state level include historic population and job growth, population and job forecasts, and traffic conditions.  Additional risk factors at the local level include regulatory constraints, critical areas, vacant and undeveloped lands, recent sales history, building permit history, and sewer and water utilities.  the local level system was applied to three case study areas.  Results generally agreed with local knowledge, yet the method offered an objective and systematic means for comparing corridors across the state fairly.      In part two, a menu of strategies for responsibly developing state routes was developed from current WSDOT practices, literature on standard approaches, and reports of novel solutions.  Strategies were classified as planning and coordination activities, non-engineering and engineering strategies, and funding/enforcement strategies.   

Authors:
Moudon, A.V., Sheikh, A., Stewart, O., Kraus, A., Hallenbeck, M. E.

Keywords:
accident rates

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Abstract:
Built environment characteristics are associated with walking, bicycling, transit use, and vehicle miles traveled (VMT). Developing built environments supportive of walking, bicycling, and transit use can help meet state VMT reduction goals. But tools are necessary to understand how changes to the built environment may translate into changes in travel. Such tools can help optimize land use and transportation investments for reduced VMT and communicate such changes to the public. This report reviews the built environment characteristics associated with travel and the tools available that utilize these built environment characteristics to estimate travel and related outcomes such as vehicle emissions and health co-benefits. Tools ranged from simple to complex, and a number of factors should be considered when applying a tool to a planning effort.

Authors:
Moudon, A. V., Stewart, O.

Keywords:
accident rates

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Abstract:
This report describes the development of geospatial sidewalk data for the King County Urban Growth Area. Prior to the development of this data set, sidewalk data in King County were limited to select jurisdictions and existed in multiple, sometimes incompatible, formats. Existing sidewalk data were collected from 30 of 40 jurisdictions and standardized to a geographic information system (GIS) data format that stores sidewalk coverage as attributes of King County street network centerlines. For each street segment, each sides was coded as full, no, or partial sidewalk coverage. An automated coding method was developed to standardize existing data when possible. Sidewalk coverage for jurisdictions with no existing sidewalk data or with data formats incompatible with automated coding were coded manually with the aid of internet mapping resources. A total of 27 jurisdictions, including unincorporated King County, were manually coded. Overall rates of agreement between automated and manual coding were 0.95, with higher rates of agreement for street segments with full and no (0.94 to 0.97) compared to partial sidewalk coverage (0.70 to 0.72).

Authors:
Moudon, A.V., Kang, B., Scully, J., Stewart, O.

Keywords:
accident rates

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Abstract:
The AASHTO LRFD, as well as other design manuals, has specifications that estimate the structural performance of a concrete mixture with regard to compressive strength, tensile strength, and deformation-related properties such as the modulus of elasticity, drying shrinkage, and creep. The Washington State Department of Transportation (WSDOT) is evaluating the performance properties of approved concrete mixtures, and verifying the measured properties and comparing them to those expected from AASHTO specifications. Factors influencing the structural behavior of concrete mixtures include the coarse aggregate source and size, paste content, water-to-cementitious ratio, and age characteristics. These factors are not integrated within AASHTO LRFD models to predict the concrete mixture’s performance. Current specifications relate most of the structural performance properties to the compressive strength, with little regard to the mixture proportions. This research was directed toward assessing the performance of the approved WSDOT concrete mixture and the sensitivity of the properties based on aggregate source and paste content. The objectives of this research were to investigate whether modifications to AASHTO LRFD specifications were required, and if so, to recommend improvements using pertinent mixture proportions. 17. KEY

Authors:
Meader, J., Janssen, D.J., Eberhard, M.O.

Keywords:
accident rates

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Abstract:
This report presents a framework to support performance monitoring for demand management related to VMT reduction. The framework consists of performance monitoring measures and a system for their collection and dissemination. The report also provides the context within which the framework would exist, and describes how it will support a wide variety of other statewide and regional needs, thus providing additional incentive for its adoption. The intent of the Framework is to not only meet the requirements of Washington state’s legislative requirement to reduce VMT per capita (RCW 47.01.440), but to do so in a way that provides WSDOT and its partner agencies with information that supports planning and programming. The report also provides an excellent framework for developing and reporting congestion-related performance measures in support of MAP-21.

Authors:
Hallenbeck,M. E., Stewart,O., Moudon,A. V.

Keywords:
accident rates

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Abstract:
WSDOT recently installed sensors on I-5 and SR 512 that greatly improved the amount and quality of traffic congestion data available in and around Tacoma and Olympia. This report examines the public’s use of WSDOT’s traveler information services providing that enhanced information to the public. It reports the results of an Internet survey that obtained the opinions of individuals who seek information on WSDOT’s traveler information website. The survey results indicated that respondents find considerable value in the traffic congestion information WSDOT provides and believe that the Department should continue to expend funding on roadway traveler information. The report also describes the range of mechanisms survey respondents used to obtain freeway congestion information and describes the ways that individuals put that information to use once they have obtained it.

Authors:
Hallenbeck,M. E., Le,Tom

Keywords:
accident rates

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Abstract:


Authors:
Hallenbeck,M. E.

Keywords:
accident rates

Abstract:
This study was conducted in cooperation with the U.S. Department of Transportation, Federal Highway Administration.  The objective of this study is to identify the key variables necessary in estimating the impact of regular washing of steel bridges on the paint and service life, recommend methods for recording data in order to most effectively estimate the benefits of bridge washing, and to develop a framework for assessing the impact of bridge washing on paint life.  A literature review was conducted to learn more about the mechanisms of corrosion.  Then a nationwide survey was sent out to state transportation agencies.  A follow-up survey was conducted in order to obtain more detailed information about certain washing programs.  It weas concluded that little information on the effects of bridge washing exist and it is only deemed beneficial based on anecdotal assumptions.  an experiment is proposed for WSDOT that will provide hard data to make a decision.

Authors:
Berman,J.W., Roeder,C., Burgdorfer,R.

Keywords:
accident rates

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Abstract:
This study is a supplement to a previous study of bridge washing practices that focused on steel superstructures.  This study examined the perceived costs and benefits of routine washing of both steel and concrete bridges, with emphasis on substructure seats and bridge decks, by exploring current practices around the U.S. A literature review was conducted in order to learn more about these elements and their failure mechanisms.  Then a nationwide survey was conducted with state DOTs around the U.S. regarding the washing practices of decks, expansion joints, and bearings.  A follow-up survey was conducted soon afterward to collect more detailed information.  A summary of the common washing practices is given in conclusion.

Authors:
Berman,J. W., Roeder,C. W., Burgdorfer,R.

Keywords:
accident rates

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Abstract:
Tests were conducted on heat-straightened and/or bent live load hanger bars used in loading bridges in the Washington State Ferry (WSF) system. Both fatigue and ultimate strength tests were conducted. The study found that when heat-straightened three times, the hanger bars have a fatigue life that exceeds their design life. The data indicated that additional heat-straightening may be possible without concern for reducing the fatigue life. The yield strength of the hanger bars was found to be unaffected by either heat-straightening or by initial bending deformations. In both cases the hanger bar yield strength exceeded nominal values. The ultimate strength was somewhat reduced by the presence of initial bending deformation.

Authors:
Berman,J. W., Chaijaroen,V.

Keywords:
accident rates

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Abstract:
The ability to fully understand and accurately characterize freight vehicle route choices is important in helping to inform regional and state decisions. This project recommends improvements to WSDOT’s Statewide Freight GIS Network Model to more accurately characterize freight vehicle route choice. This capability, when combined with regional and sub-national commodity flow data, will be a key attribute of an effective statewide freight modeling system. To come to these recommendations, the report describes project activities undertaken, and their outcomes, including 1) a review of commercially available routing software, 2) an evaluation of the use of statewide GPS data as an input for routing analysis, and 3) the design, implementation, and evaluation of a survey of shippers, carriers, and freight forwarders within the state. The software review found that routing software assumes least cost paths while meeting user specified constraints, and it identified criteria for evaluation in the subsequent survey. The GPS data evaluation showed that significant temporal shifting occurs rather than spatial route shifting, and it revealed significant limitations in the use of GPS data for evaluating routing choices, largely because of the read rate. Among the survey results was that the first priority of shippers, carriers, and freight forwarders is to not only meet customer requirements, but to do so in the most cost-efficient way. From a latent class analysis of routing priorities, we discovered that distance-based classification best clusters similar routing behavior. The report includes recommendations for implementing this within the Statewide Freight GIS Network model.

Authors:
Rowell,M., Gagliano,A., Wang,Z., Goodchild,A., Sage,J., Jessup,E.

Keywords:
accident rates

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Abstract:
The Washington State Department of Transportation (WSDOT) frequently employs deep pile or caisson bridge foundations for its bridge structures. Deep pile and drilled shaft foundations are increasingly important for seismic design in Washington state, because of increased seismic design load demands in bridge design specifications. A common caisson is a reinforced concrete filled tube caisson. Although these types of foundation elements are common, there are few guidelines on their design. As a result, current WSDOT design methods are conservative and neglect the many benefits provided by composite action of the concrete and the steel tube, which may result in increased cost and size of the foundation. Recent research on composite concrete filled steel tubes (CFT) shows significant benefit for applications using CFT elements, in particular that CFT elements can develop more lateral resistance and greater inelastic deformation capacity with less deterioration of resistance than reinforced concrete elements of the same weight and diameter. Hence the use of this composite action permits smaller diameter and shorter caisson foundations resulting in cost savings associated with a smaller piles and drilled shafts, less material and reduced construction time and cost. This research involves consideration of the composite properties of CFT members with internal reinforcement, and this special case of internally reinforced CFT is identified as RCFT in this report. The research study used analytical tools verified using past experimental and analytical research on CFT members and foundation connections without internal reinforcement. The research included comprehensive review of past research results including experiments and analysis of CFT and RCFT elements and connections. Design models were evaluated and compared to prior test results to determine their accuracy and reliability. A comprehensive analytical study was performed to extend this prior research to current WSDOT RCFT applications. The analytical studies were calibrated to past experimental results to document their accuracy, and the analysis included development of basic design models, fiber or section based analysis, and detailed continuum based models. No experiments were included in this initial study, but observations from prior experimental research were to be used to support the work. The goals of this preliminary study were to develop initial answers to uncertainly in the design process of these components and their connections to permit the WSDOT to begin to employ the benefits of composite action for these sub-structural systems. To that end, specific design recommendations from this preliminary research study are provided. Finally, an overview of the additional research needed to further develop the deep foundation system is provided.

Authors:
Roeder,C. W., Lehman,D. E.

Keywords:
accident rates

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Abstract:
The durability of Portland cement concrete (PCC) has long been identified as a concern by transportation communities around the United States. In this study, the long-term performance of two batches of concrete incorporating either low-degradation (LD) or normal (NM) aggregates subjected to freezing and thawing conditions was experimentally studied. The freezing and thawing test method (ASTM C666) was followed to condition all the test samples. Dynamic modulus and fracture energy for both groups of concrete samples after different numbers of freeze-thaw cycles were measured through nondestructive modal and cohesive fracture tests, respectively. Due to the higher air content in LD concrete, surface scaling was less severe under frost action. Test results showed that different aggregate degradation has an important effect on the freeze-thaw resistance of the concrete and the rate of decrease in fracture energy with number of freeze-thaw cycles for the LD concrete is higher than for the NM concrete. Compared to the dynamic modulus of elasticity, the fracture energy is a more sensitive parameter for evaluating concrete degradation caused by the frost action. Thus, the degradation of aggregate in concrete can be better evaluated by the cohesive fracture test. Additional research is needed to identify an appropriate threshold for when aggregate degradation properties become a concern. Until that time, it is recommended that WSDOT maintain their current restrictions on using low-degradation aggregates in concrete.

Authors:
Qiao,P., McLean,D. I., Chen,F.

Keywords:
accident rates

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Abstract:
This study assessed the Safe Routes to School (SRTS) program in five states: Florida, Mississippi, Texas, Washington, and Wisconsin. A database of all SRTS projects announced for funding and all schools affected by these projects was developed. The database was analyzed to (1) quantify the SRTS programs’ impact in the five states and compare them to SRTS programs nationally, (2) assess the SRTS programs’ effectiveness in increasing rates of walking and bicycling to school, and (3) identify characteristics of SRTS projects associated with greater increases in walking and bicycling to school. In the five states, 569 SRTS projects were announced for funding through April 2011. These projects reached more than 1,410 schools and 781,180 children—roughly 10 percent of the PK-8 grade public school population in the five states. Engineering components were featured in most projects, and sidewalks were the most common engineering activity. Among completed SRTS projects with before and after travel data, rates of walking increased by 45 percent (from 9.8 percent to 14.2 percent), bicycling increased by 24 percent (from 2.5 percent to 3.0 percent), and all active travel to school (ATS) increased by 37 percent (from 12.9 percent to 17.6 percent). Increases in rates measured at the project level were statistically significant. Before and after travel data were only available for projects with an engineering component. Among these projects, those that affected fewer schools and students, as well as those with encouragement and education components tended to perform better. These relationships, however, were not statistically significant. The only statistically significant relationship found was a negative correlation between baseline rates of bicycling to school and increases in rates of bicycling to school, suggesting that SRTS projects may be more effective at encouraging bicycling to school where few children already do so. The results of this study offer preliminary evidence that the SRTS program is achieving one of its primary goals of increasing rates of walking and bicycling to school and that SRTS funds are delivering a return on investment. It identified some trends of more successful projects, which warrant further investigation. As more projects end, the research framework established in this study can be used to further explore these findings and refine programs that help children safely walk or bicycle to school.

Authors:
Moudon,A. V., Stewart,O.

Keywords:
accident rates

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Abstract:
Nonlinear analyses of soils, structures, and soil-structure systems offer the potential for more accurate characterization of geotechnical and structural response under strong earthquake shaking. The increasing use of advanced performance-based design and evaluation procedures will require consideration of long-return-period motions for all structures, especially in western Washington where high seismicity is a concern and long-return-period motions are likely to be strong enough to induce nonlinear, inelastic response in soil deposits and structures. Nonlinear analyses require the specification of acceleration time histories as input; this requires the analyst to identify input motions that are consistent with the ground motion hazards at the site of interest. A considerable level of research effort has been directed toward the development of procedures for selection and scaling of earthquake ground motions for the purpose of using them in nonlinear structural analysis. This research has shown that structural response of buildings can be quite sensitive to the selection and scaling of ground motions used in nonlinear analyses. While the sensitivity of bridge structures to input motion characteristics has not been studied as explicitly as that of building structures, the response of bridges is also expected to be significantly influenced by input motion characteristics. As a result, engineers have identified the need for software tools that will automate, to at least a large degree, the process of identifying suites of ground motions that are most appropriate for use in nonlinear response analyses. Along with this report, a piece of software, SigmaSpectraW, was created for WSDOT to do just that.

Authors:
Kramer,S. L., Arduino,P., Sideras,S. S.

Keywords:
accident rates

Abstract:
The Seattle multi-modal corridor data set covers the Interstate 5 freeway corridor from the King/Pierce County line in the south to approximately the City of Everett in the north. The arterial data included in the data set cover the major City of Seattle north–south arterials west of I-5 and east of Puget Sound. The specific geographic areas covered by the data are shown in figures 1 and 2. The data set contains 6 months of data, collected from May 1, 2011, to October 31, 2011.

Authors:
Hallenbeck,M. E., Wang,Y., Ishimaru,J. M., Ma,X., Richards,M., Corey,J.

Keywords:
accident rates

Abstract:
Travel time data had been very difficult to collect until recently. Current attempts at exploiting short-range communication protocols that rely on unique identifiers, primarily Bluetooth, have significantly simplified the travel time collection task. Many transportation agencies are now considering using Bluetooth travel time estimates to feed a variety of applications, such as user information systems. As Bluetooth-based travel time data collection increases in popularity, investigating the errors that are characteristic of this detection type becomes more important. A Bluetooth sensor, called the Media Access Control Address Detection (MACAD) system, was developed for travel time data collection in this study to facilitate testing system configurations and allow for future deployments. Three types of antennae and three different sensor arrangements were tested to determine the effects of these variables on travel time error. The collected travel time data were compared to license plate reader data, which, because of their relatively small detection zone for vehicle license plate recognition, were taken as the ground truth travel time. A regression model was used to investigate whether travel time error can be predicted with observable explanatory variables. Descriptive statistical analysis was also employed to evaluate the impacts of individual variables on the travel time error. The results suggested that a combination of sensors is desirable, despite the potential loss of accuracy, as the higher matching rates obtained by the system will improve sample size and reduce random error rates. Findings of this study are helpful to transportation professionals attempting to understand the errors associated with the Bluetooth-based travel time data collection technology and to configure the sensors to mitigate the errors. 17. KEY

Authors:
Wang,Y., Malinovskiy,Y., Wu,Y-J, Lee,U. K.

Keywords:
accident rates

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Abstract:
This report addresses the question: What does it take to achieve and maintain sustainable urban roadside restoration projects in Western Washington that provide for necessary roadside functions at lowest lifecycle cost? It makes recommendations under five categories: general, agency communication and process, design, construction, and maintenance. It identifies two major problems common to urban roadside: the establishment of transient encampments and intense invasive weed pressures. Urban roadside environments are extremely varied and serve many functions; therefore, the report does not recommend a single type of roadside planting or maintenance suitable for all situations. Integrated Vegetation Management is a key tool for planning and implementing urban roadside maintenance.

Authors:
Robertson,I., Smith,L.

Keywords:
accident rates

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Abstract:
The underwater noise from impact pile driving was studied by using a finite element model for the sound generation and a parabolic equation model for propagation. Results were compared with measurements taken with a vertical line array deployed during tests at the Vashon Island ferry terminal near Seattle in November 2009. Tests showed that the dominant underwater noise produced by impact driving is from the Mach wave associated with the radial expansion of the pile that propagates down the pile after impact at supersonic speed. The effectiveness of surrounding the pile in the water with a double-walled steel tube, also called a temporary noise attenuation pile (TNAP), to reduce the underwater sound caused by pile driving operations was also investigated. Tests and analysis showed that the noise attenuation capability of the TNAP was limited to approximately 10 dB because of the unconstrained propagation of Mach waves directly from the sediment into the water. 17.

Authors:
Reinhall,P. G., Dahl,P. H.

Keywords:
accident rates

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Abstract:
This report documents the results of applying a previously developed, standardized approach for evaluating intelligent transportation systems (ITS) projects to 17 ITS earmark projects. The evaluation approach was based on a questionnaire to investigate technical, management, and organizational lessons learned. The report includes an evaluation report for each of the 17 ITS projects. Each report includes a discussion of the following: · Background · Project description · System usage and benefits · Cost, operations and maintenance · Architecture and standards · Lessons learned.Most of the lessons learned in this evaluation phase were similar to those documented in previous evaluations.

Authors:
Porter,R. D., McCormack,E. D., Briglia,P. M.

Keywords:
accident rates

Abstract:
Safe Routes to School (SRTS) programs support children safely walking and biking to and from school. Each state Department of Transportation (DOT) awards federal grant money to proposal applications made by local SRTS programs. Because demand for federal SRTS funding far exceeds most states’ budgets for their program, state DOTs must carefully select the SRTS proposals that receive an award. By definition, most local program proposals that meet the federal guidelines to receive SRTS grant money will include elements that contribute to pedestrian safety. As a result, state DOTs that wish to leverage their SRTS funds are faced with the difficult task of choosing those proposals with the greatest potential to successfully increase the safety and number of children walking or biking to school. This report compares how five state DOTs – Florida, Mississippi, Texas, Washington, and Wisconsin – select the most promising SRTS proposals for funding. It reviews how the five states approach the selection process by considering grant types, SRTS plans, eligibility requirements, program distribution policies, proposal review processes, and established selection criteria. The selection processes and criteria used are reviewed to highlight examples of best practices that consider (1) the four common barriers to walking and biking to school (distance, income, parent values and parent concerns), (2) the “five E’s” commonly used to classify SRTS program elements (engineering, education, encouragement, enforcement, and evaluation), and (3) the five conceptualized stages of an SRTS program (existing conditions, planning, proposal, implementation, and assessment of outcomes). The results of this review are insights into how the five state DOTs define an effective SRTS program and how they prioritize awards for the many good SRTS program proposals they receive. Examples of effective selection practices are identified as a basis for making specific recommendations on what constitutes a promising proposal selection process that awards programs with the highest potential to increase the safety and number of children walking or biking to school. An appendix contains documentation on the original SRTS proposal selection protocols used by the five contributing state DOTs.

Authors:
Moudon,A. V., Stewart,O., Lin,L.

Keywords:
accident rates

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Abstract:
Despite the fact that travel speed and reliability on numerous segments of the high-occupancy vehicle (HOV) lanes of the central Puget Sound freeway network are not meeting the adopted state performance standard, trends suggest that HOV travel demand is expected to increase. This study was conducted to evaluate the performance of Interstate 5 HOV lanes between Federal Way and Everett, Washington, focusing on congestion; to identify congestion bottleneck segments and potential causes; and to develop a range of potential short-term (0 to 5 years) enhancements to improve HOV traffic flow at bottlenecks. A review of estimated speeds and vehicle volumes for 2007 determined that the I-5 HOV corridor as a whole does not meet the state standard during the peak travel periods in the dominant direction of traffic (inbound to Seattle from the south and north in the AM peak, outbound from Seattle in the PM peak). Eight HOV lane segments were specifically identified as bottleneck locations of heavy congestion.The report details possible causes of congestion in these areas: heavy usage of the HOV lane, roadway geometry, lane friction, merging conflicts, slow vehicles, and incidents. The report also discusses short-term options for addressing congestion at these locations: implementing general purpose on-ramp metering, implementing inside HOV on-ramp metering, moving the HOV lane endpoint approach the northbound express lane entrance, strengthening the incident response program, introducing buffer separation, reconfiguring express lane ingress/egress, introducing active traffic management, reserving HOV lanes for bus transit only, and changing the occupancy requirement from 2+ to 3+. The advantages, disadvantages, and other issues related to these options are also discussed.

Authors:
Ishimaru,J. M., Hallenbeck,M. E., Wright,D., Kang,J.

Keywords:
accident rates

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Abstract:
This project investigated the basic relationship of incidents to delay on Puget Sound area freeways. The intent was to determine the amount of delay caused by incidents and the benefits obtained from the incident response actions taken by the Washington State Department of Transportation (WSDOT). The analysis was based on data from 2006 and included all days in 2006. The study area included I-5 from SR 526 in the north to S. 320th in Federal Way in the south; all of I-90 west of milepost 19.5, which is east of Front Street in Issaquah; all of I-405; SR 167 from I-405 to SR 18; and all of SR 520. The study showed that incidents, including crashes, do not, in and of themselves, cause measurable delay. They cause delay only when the disruption they create causes functional capacity to fall below actual demand. However, the researchers calculated that the average incident that does not involve a lane closure results in 576 vehicle-minutes of delay per minute the incident is present. If the incident closes a lane, the effect of that lane closure adds 814 vehicle-minutes of delay per minute of closure. For the 2006 study year, a conservative estimate is that crashes and other traffic incidents (including disabled vehicles, debris, and other events requiring WSDOT intervention to remove hazards) cost travelers 5,300,000 vehicle-hours of delay, in addition to typical congestion delay, on the Puget Sound region’s freeway system. That is roughly 30 percent of the total delay from all causes that occurred on these roadways. Approximately 11 percent of the total delay (1,950,000 veh-hrs) was the result of reported vehicle crashes. The study also determined that crash rates increase substantially when delays caused in part by incidents occur. In fact, a simple summary of the available data indicated that crash rates essentially double in corridors slowed by unexpected incident-related queuing. Consequently, because reducing the duration of incidents results in faster clearance of incident-related queuing, it will also have a significant safety benefit, as measured in a reduced crash rate.

Authors:
Hallenbeck,M. E., Pham,C., Watkins,K.

Keywords:
accident rates

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Abstract:
The HOT lanes on SR 167 south of Seattle, Washington, are separated from their respective general purpose lanes by a double white lane line. Legal access to the HOT lanes is limited to four locations southbound and six locations northbound. This study examined the frequency with which motorists illegally cross the double white lane line, rather than waiting for one of the legal access points. The study determined the locations and operating conditions under which violations most commonly occur.The study showed that during most times of the day and along most portions of the corridor, the number of illegal entry and exit movements is negligible. However, at a small number of locations and under specific congestion conditions, violation rates can exceed 1 per minute. The worst violation location is northbound, north of the S. 180th St on-ramp, just before the end of the northbound HOT lane and after the last toll collection gantry. Violations at this location appear to be caused by the three main factors: 1) In anticipation of the lane becoming a general purpose lane in less than another 500 feet, some motorists “jump in early.” 2) This location is often the point to which the queue from the I-405 interchange ramp backs up. Violation rates increase significantly near the upstream end of any queue. 3) Many vehicles entering the freeway at the S. 180th St ramp move as directly as possible to the left lane of the freeway and then merge into the HOT lane. In congested conditions, these movements result in lane-line violations because the slow, heavy traffic allows the weave process to occur in a short distance. Under faster free flow conditions, this weave movement requires a much longer distance, resulting in vehicle merges at the intended legal locations.

Authors:
Hallenbeck,M. E., Corey,J.

Keywords:
accident rates

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Abstract:
This report provides guidance to the Washington State Department of Transportation (WSDOT) in creating, supporting and enhancing Growth and Transportation Efficiency Centers (GTECs), especially those centers located within suburban cities. The report examines the goals of the GTEC program and makes a variety of recommendations for growing the program and expanding its effectiveness in reducing peak period SOV use under a variety of different budgetary scenarios.

Authors:
Hallenbeck,M. E., Carlson,D.

Keywords:
accident rates

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Abstract:
In order to support WSDOT in development of the Washington State Freight Mobility Plan, this document presents recommendations for criteria to be used in defining the Washington state truck intermodal network. The state does not have an existing definition of the freight truck-intermodal system. To establish the criteria, this project reviewed methods used by other states, identified the facilities in Washington specified by the National Highway System, and compared these facilities to those identified by regional planning organizations. Finally, recommendations are made for criteria to use in identifying the truck intermodal network for Washington.

Authors:
Goodchild,A.

Keywords:
accident rates

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Abstract:
Life Cycle Assessment (LCA) is a tool that can be used to identify ways to decrease the environmental impact of a product or process and to inform decision makers of the consequences of changes to the product or process. LCA encompasses all aspects of a process or product from “cradle to grave”, including material extraction, transport, production, maintenance, and removal or recycling. This study is a comparative LCA of three different replacement options for an aging Portland cement concrete (PCC) highway: Replacement with a new PCC pavement, replacement with hot mix asphalt (HMA) pavement, and cracking, seating and overlaying (CSOL) the existing pavement with HMA. Each LCA includes an appropriate maintenance schedule so that the pavements will have a 50 year life span and can be reasonably compared. The environmental impacts have been assessed according to common environmental concerns, such as global warming potential and acidification. This paper summarizes those impacts and provides information and recommendations to build “greener” highways in Washington State.

Authors:
Weiland,C. D., Muench,S. T.

Keywords:
accident rates

Abstract:
Traffic incidents cause approximately 50 percent of freeway congestion in metropolitan areas, resulting in extra travel time and fuel cost. Quantifying incident-induced delay (IID) will help people better understand the real costs of incidents, maximize the benefit-to-cost-ratio of investments in incident remedy actions, and facilitate the development of active traffic management and integrated corridor management strategies. Currently, a number of algorithms are available for IID quantification. However, these algorithms were developed with certain theoretical assumptions that are difficult to meet in real-world applications. Furthermore, they have only been applied to simulated cases and have not been sufficiently verified with ground-truth data. To quantify IID over a regional freeway network using existing traffic sensor measurements, a new approach for IID estimation was developed in this study. This new approach combines a modified deterministic queuing diagram with short-term traffic flow forecasting techniques to overcome the limitation of the zero vehicle-length assumption in the traditional deterministic queuing theory. A remarkable advantage with this new approach over most other methods is that it uses only volume data from traffic detectors to compute IID and hence is easy to apply. Verification with the video-extracted ground truth IID data found that the IID estimation errors with the new approach were within 6 percent for the two incident cases studied. This implies that the new approach is capable of producing fairly accurate freeway IID estimates using volumes measured by existing traffic sensors. This approach has been implemented on a regional map-based platform to enable quick, convenient, and reliable freeway IID estimates in the Puget Sound region.

Authors:
Wang,Y., Yu,R., Lao,Y., Thomson,T.

Keywords:
accident rates

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Abstract:
Animal-vehicle collisions (AVCs) have been increasing with increases in both animal populations and motor vehicle miles of travel and have become a major safety concern nationwide. Most previous AVC risk studies have not considered factors related to human behavior or the spatial distribution of animal populations in depth because of missing datasets or the poor quality of data. The two common sources of data—the Collision Report (CRpt) and Carcass Removal (CR) datasets—are often found significantly different. To address these data issues, two approaches were followed in this research. In the first approach, a fuzzy logic-based data mapping algorithm was developed to obtain a more complete AVC dataset from the CRpt and CR data. In comparison to the original CR dataset, the combined dataset increased the number of AVC records by 13~22 percent. This combined dataset was used to develop and calibrate a microscopic probability (MP) model that can explicitly consider drivers’ behaviors and the spatial distributions of animal populations. In the second approach, a Diagonal Inflated Bivariate Poisson (DIBP) regression model was developed to fit the two datasets simultaneously. The DIBP model can effectively identify the overlapping parts of the two datasets and quantify the impacts of road and environmental factors on AVCs. Both proposed models used the CRpt and CR data collected from ten selected study routes in Washington state. The MP model results showed that variables including number of lanes and animal habitat areas are significantly associated with the probability of animals crossing the highway. Two factors, speed limit and truck percentage, have impacts on the probability of a driver’s ineffective response. A wider median may decrease the probability of an animal failing to avoid a collision. The DIBP results showed that speed limit, restrictive access control, and roadway segment length have an increasing relationship with AVCs. Furthermore, hotspots (high risk roadway segments) were identified for all the study routes on the basis of the modeling and data analysis results. These quantitative results will help WSDOT develop countermeasures to AVCs.

Authors:
Wang,Y., Lao,Y., Wu,Y-J, Corey,J.

Keywords:
accident rates

Abstract:
The shadows from large over-water structures built on nearshore habitats in the Puget Sound can reduce prey abundance and disrupt juvenile Pacific salmon (Oncorhynchus spp.) migratory behavior with potential consequences on survival rates. As part of an ongoing project to reduce the effects of ferry terminals on juvenile salmon, this study looked at the effectiveness of a fiber optic lighting system at mitigating dock shading impacts on juvenile salmon behavior. We conducted intensive visual observations, snorkel surveys, and video filming surveys at the Port Townsend Ferry Terminal (dock) from March through August 2008 and 2009 to test whether migrating salmon reacted to changes in light beneath the terminal and whether evident reactions by the salmon were moderated by the fiber optic lighting system. We found that during high tides shoals of juvenile salmon (primarily pink salmon O. gorbuscha) were reluctant to swim under the dock and also under the shaded areas. Overall, less than 15 percent of juvenile salmon shoals penetrated under the terminal, and they typically remained within a few meters from the dock. No salmon swam completely under the dock during our observations in the study period. As a consequence of this dock avoidance behavior, ferry terminals likely delay migration for some juvenile salmon (pink salmon) by several hours per dock encounter, during high tide periods, daylight hours and on sunny days. Our results also indicated that light transmitted or installed under some old and new terminals could mitigate dock shading impacts on juvenile salmon. However, our experience testing both fiber optic-transmitted natural and in situ artificial (halogen) light suggests that such light mitigation systems will need to (1) be more powerful, (2) be regulated to light only shaded areas, (3) operate on a natural light spectrum, and (4) distribute light over a wide area. The impacts of large over-water structures on juvenile salmon behavior likely alter juvenile salmon migration behavior in shallow nearshore waters, but with an unknown impact to growth and survival. The use of artificial light is a promising mitigation method because fish appeared to respond at a low light level. However, our results were not sufficient to determine whether artificial light could completely mitigate the effects of the dock and eliminate juvenile salmon avoidance behaviors.

Authors:
Simenstad,C., Ono,K., Toft,J. D., Southard,S. L., Soboeinski,K. L., Borde,A.

Keywords:
accident rates

Abstract:
Washington State Department of Transportation Local Programs Division requested the creation of a Resource Planning Index (or “Index”) for use in benchmarking and tracking the stewardship performance of investments associated with Washington’s Scenic and Recreational Highways. A GIS analysis was performed to develop a unique Index value for each 1000 feet of roadway. The Index value was calculated based on the proximity of features of interest associated with specific opportunities for protecting, preserving, or enhancing resources associated with the state Scenic and Recreational Highways. This Index may be used in preliminary assessments of locations where there may be a confluence of such opportunities. As always, a local scale analysis of the location should assess exactly what opportunities exist there and whether a proposed project would actually provide the desired benefit or impact.

Authors:
Ramsey,K.

Keywords:
accident rates

Abstract:
The concrete pavements that were originally constructed in Washington State as part of the interstate construction program have performed remarkably well considering the dramatic increase in the anticipated traffic loads. To date, the primary distress on the concrete pavements in Washington State has been in the form of joint faulting (due to lack of dowel bars and underlying base/subgrade conditions), longitudinal cracking (which is believed to have occurred 3 to 5 years after construction) and wear due to studded tires. A number of factors have contributed to the long-life of these concrete pavements, such as, short joint spacing (usually 15 ft – 4.6 m), thickness (8-9 inches, 200-225 mm) and aggregate quality. However, a number of design modifications have evolved over time to improve pavement performance. These include the use of dowel bars, dowel bar type, mix design, hot mix asphalt base, joint design and joint spacing. This research documents the design and performance of the concrete pavements built in the 1960’s, summarizes the design modifications and resulting pavement performance that has taken place over the last 40 years, summarizes the current construction practices and discusses

Authors:
Muench,S. T., Pierce,L., Uhlmeyer,J., Anderson,K.

Keywords:
accident rates

Abstract:
This report summarizes the work and findings from WA-RD 744. This work consisted of four separate efforts related to best practices for portland cement concrete (PCC) pavement design and construction: (1) a review of past and current PCC pavement, (2) an analysis of PCC pavement studded tire wear on the WSDOT network, (3) a life cycle assessment (LCA) of PCC pavement rehabilitation options and (4) an analysis of the effects of loop detector installation on PCC pavement life. Key findings are: (1) outstanding issues to resolve with PCC pavement include the impact of smaller maximum aggregate size, new dowel bar materials, and shorter joint spacing, (2) there is no effective means to mitigate studded tire wear, (3) stud wear is typically in the range of 0.04-0.09 mm/yr but tends to occur more quickly early on in pavement life, (4) excessive stud wear problems are limited and not a widespread issue, (5) an aggregate hardness program like Alaska’s can help ensure stud wear does not become a major issue on newly constructed pavements, (6) life cycle assessment (LCA) can be a useful information tool and tends to show that crack, seat and overlay rehabilitation of aged PCC pavement provides many environmental advantages; and (7) current loop embedment practices do not seem to affect pavement life however previous practices may have. 17.

Authors:
Muench,S. T.

Keywords:
accident rates

Abstract:
This report presents the results of phase one of a two phase study designed to support state-level management of the Federal Highway Administration Safe Routes to School (SRTS) program. The study aims to achieve three objectives: (1) identify and use existing tools to establish benchmarks for children walking and biking to school, (2) provide recommendations for future allocation of SRTS funds, and (3) identify methods and tools to continue to evaluate the effectiveness of SRTS investments. Phase one focused on the first objective. Rates of walking and biking to school were found to vary considerably. Therefore, benchmarks of children walking and biking to school should come from individual schools. The best tool for establishing these benchmarks was the National Center for Safe Routes to School (NCSRTS) Student Travel Tally. The second two objectives were only explored in phase one. A literature review identified four major barriers to walking and biking to school that could be used to help filter program applications. Data collected by this study, the NCSRTS, and other agencies can contribute to SRTS project evaluations but because SRTS programs vary from state to state and the program is relatively new, many data are incomplete. Consistent, standardized SRTS data collection is necessary to support robust project evaluations. These preliminary findings will be explored further during phase two.

Authors:
Moudon,A. V.

Keywords:
accident rates

Abstract:
16. ABSTRACT Although trucks move the largest volume and value of goods in urban areas, relatively little is known about their travel patterns and how the roadway network performs for trucks. The Washington State Department of Transportation (WSDOT), Transportation Northwest (TransNow) at the University of Washington, and the Washington Trucking Associations have partnered on a research effort to collect and analyze global positioning system (GPS) truck data from commercial, in-vehicle, truck fleet management systems used in the central Puget Sound region. The research project is collecting commercially available GPS data and evaluating their feasibility to support a state truck freight network performance monitoring program. WSDOT is interested in using this program to monitor truck travel times and system reliability, and to guide freight investment decisions. The researchers reviewed truck freight performance measures that could be extracted from the data and that focused on travel times and speeds, which, analyzed over time, determine a roadway system's reliability. The utility of spot speeds and the GPS data in general was evaluated in a case study of a three-week construction project on the Interstate-90 bridge. The researchers also explored methods for capturing regional truck travel performance.

Authors:
McCormack,E. D., Ma,X., Klocow,C., Currarei,A., Wright,D.

Keywords:
accident rates

Abstract:
This report describes and evaluates parking tax options for possible implementation by the City of Seattle. A commercial parking tax is a special tax on priced parking. A nonresidential parking tax (NRPT) is a special tax that applies to both unpriced and priced parking. Commercial parking taxes discourage the pricing of parking and concentrate impacts in a few areas. Non-residential parking taxes distribute cost burdens more broadly, encourage property owners to manage parking supply more efficiently, which tends to reduce total parking costs, reduce automobile traffic, and reduce sprawl. Although non-residential parking taxes are more challenging to implement, they tend to support more of Seattle’s strategic planning objectives.

Authors:
Litman,T., Carlson,D., Blumenthal,A., Lee,J.

Keywords:
accident rates

Abstract:
Studded tires are legal in Washington State and are typically allowed to be used each winter between the months of November and April. They are known to cause accelerated wheelpath wear resulting in additional pavement preservation costs. While studded tire use rates are hard to quantify, the volume of studded tire equipped vehicles is rather consistent across Washington State. This report uses Washington State Pavement Management System (WSPMS) data to explore studded tire wear on Washington State Department of Transportation (WSDOT) roads. The average Portland Cement Concrete (PCC) pavement wears at about 0.01 inches per 1 million studded tire vehicle passes. The highest wear rates are near 0.5 mm/yr on I-90 in the Spokane area, while the lowest wear rates are in the range of 0.04-0.09 mm/yr in many locations. Stud wear rates are generally higher in the first 5 years of PCC pavement life and much less thereafter.While excessive stud wear problems are limited and not a widespread issue, specific locations with high stud wear rates are alarming. While several strategies have been attempted to limit stud wear, none outside of diamond grinding has proven effective. There are a few new materials (resin modified pavements, PCC surface texture techniques) that may yet prove effective. Tests to determine the susceptibility of aggregate sources to stud wear are generally not reliable, however the Micro-Deval seems to be the most favorably rated. The WSDOT current practice of designing in an extra inch of pavement to account for future thickness loss associated with diamond grinding is sound policy and should be continued. As more PCC pavement in Washington State is due for replacement, WSDOT should consider a hardness specification program like Alaska’s in order to prevent the use of susceptible aggregate sources.

Authors:
Cotter,A., Muench,S. T.

Keywords:
accident rates

Abstract:
The State of Washington has established benchmarks for reducing vehicle miles travelled (VMT). The ambitious targets call for VMT reductions of 18 percent by the year 2020, 30 percent by the 2035, and 50 percent by mid century. This report discusses estimates and examines impacts of VMT reduction strategies on selected groups and geographic areas mandated by state legislation. The five groups and areas were small businesses whose employees cross county lines to get to work, low-income residents, farmworkers - especially migrant workers, distressed counties with more than half the land in federal or tribal ownership. The study defined these groups and areas, established a typology of VMT reduction strategies, and made assumptions about behavior and trip lengths based on available literature. It then estimated impacts on the selected groups and areas and suggested several implementation steps and areas for further research.

Authors:
Carlson,D., Howard,Z.

Keywords:
accident rates

Abstract:
The purposes of this project were to gain a better understanding of the benefits of providing in-vehicle congestion informa­tion and to determine whether any detectable congestion level changes resulted from providing this information. The project tested an in-vehicle traffic map device (TrafficGauge) using 2,215 participants from the Puget Sound region. Three rounds of surveys (Entry, Daily and Exit) took place between November 2007 and May 2008 in which participants used the TrafficGauge for six months. The project also analyzed a roadway corridor to determine, in instances of unusual freeway congestion, how traveler’s behavior affects congestion on alternative roadways. The analysis looked for correlations between the per­formance of the study corridor’s three freeways and four arterials using conditional probability tables. Most of the survey participants were young to middle-age males, well educated with middle or high incomes. The entry survey demographic data indicated that the participants were not representative of the general population but they were proba­bly representative of those most likely to seek and pay for traveler information, particularly information delivered by an in-vehicle congestion map device. On half the occasions when participants reported changing routines in the daily surveys, they reported not receiving any benefits. For the entire study, 25 percent of participants reported not benefiting at all from the device. Participants who changed routines saved time a mean number of 1.6 times. The mean amount of time saved on those instances was a little over 30 min­utes. Thirty-two percent of participants indicated that they did not save any time by using the device. Over 59 percent of the participants indicated that the information provided by the device reduced their level of stress. The study participants could be divided into three groups. One (about 20 percent) thought highly of the device, were con­fident that it had saved them considerable time and stress, and would purchase the device. Another (between 21 percent and 26 percent) saw little value in either the device or the information that it conveyed and would not purchase the device. The third, and largest, group saw value in the device and occasionally benefited from the information it provided. They did not, however, think that these benefits warranted purchasing the device. The corridor analysis indicated that even without arterial performance information, some travelers seek alternative routes when the freeway becomes congested. The corridor analysis confirmed that many travelers diverted either on the basis of what they see on the roadway or what they get from en-route traffic information sources. Even the modest levels of diversion observed in this study increased arterial congestion, especially near freeway ramps. This visible arterial congestion near the freeway discouraged diversion. Consequently, providing arterial performance information on the entire arterial via in-vehicle devices is likely to increase initial diversion, thereby degrading arterial performance. Roadway agencies will, therefore, need to make traffic management of the ramps and arterial segments that connect the alternate routes a priority.

Authors:
Briglia,P. M., Hallenbeck,M. E., Fishkin,E., Wu,Y-J

Keywords:
accident rates

Abstract:
The installation of loop detectors in portland cement concrete pavement (PCCP) may shorten affected panel life, thus prematurely worsening the condition of the overall pavement. This study focuses on the performance of those loop embedded panels (LEP) by analyzing pavement data collected by WSDOT, and comparing it to the overall pavement performance on I-5 in King County. The results were divided by non-rehabilitated, diamond ground and dowel bar retrofit and diamond ground PCCP, as was done in the reference paper, to facilitate comparison. Overall, LEP perform worse – regarding panel cracking – in comparison to loop free panels (LFP), except on the small section of I-5 that has been Dowel Bar Retrofitted and Diamond grinded. For the non-rehabilitated PCCP, the difference between LEP and LFP with 1 crack is less than 1% but more than twice as many LEP have what is considered “failed” panels (2 or more cracks) than LFP. This might indicate that the loop installation affects more the severity of panel cracking than being the cause for it. Using these results and assuming panel replacement of the cost of $20,000 each, the cost of loop installation to the pavement was found to be $560 each. Traffic simulation was done for a section of I-5 to calculate delay due to lane closures, which loop detector installation constitutes. The user cost associated with the delay is a substantial part of the overall cost of loop installation, 40 – 60 percent depending on the number of affected lanes on the freeway. If user costs are accounted for, the overall cost of video and loop detection systems can be comparable.

Authors:
Bodvarsson,G. A., Muench,S. T.

Keywords:
accident rates

Abstract:
To improve our understanding of how tolling is likely to affect low-income populations in the Puget Sound region, this report accomplishes four objectives. It 1. reviews existing research on the impacts of tolling on low-income households in the United States 2. assesses the usefulness of currently available Washington and Puget Sound data for estimating the impacts of tolling on low-income populations 3. develops a preliminary estimate of the impacts of tolling on low-income populations living in the Puget Sound region 4. suggests data collection and methodological strategies for future research that would yield better estimates of the impacts of tolling on low-income populations in the Puget Sound region and other parts of Washington state.

Authors:
Plotnick,R., Romich,J., Thacker,J.

Keywords:
accident rates

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Abstract:
The Washington State Department of Transportation (WSDOT) maintains approximately 2,400 lane miles of concrete pavements, many of which are on the heavily traveled interstate highway network. Many of these concrete pavements have more than doubled their intended performance life. Due primarily to traffic disruption, WSDOT has long recognized the potentially costly rehabilitation and reconstruction needs of the aging concrete pavement network. In 1993, WSDOT began dowel bar retrofitting its faulted concrete pavements. Dowel bar retrofit has had varied success in the United States, primarily due to construction techniques. In Washington State overall, dowel bar retrofit has been successful and has been determined to be a cost effective rehabilitation treatment. What is still unknown are the most applicable time or condition level (i.e. faulting and cracking condition) for applying dowel bar retrofit, its long‐term performance, and its failure mechanism. The outcomes of this study include guidelines for dowel bar retrofit project selection and construction best practices, a summary of dowel bar retrofit performance in Washington State, and estimated dowel bar retrofit project costs.

Authors:
Pierce,L., Muench,S. T.

Keywords:
accident rates

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Abstract:
The objectives for this project were to explore community transportation design policy to improve collaboration when state highways serve as local main streets, determine successful approaches to meet the federal requirements for visioning set forth in SAFETEA-LU [23USC135(f)(3)(B)(ii)], find ways to assist local agencies in improving their grant applications to WSDOT, identify new ways to translate context sensitive design guidance into practice, and support staff and organizational development by connecting the architecture profession and transportation engineering. For this study, student researchers participating in University of Washington’s Storefront Studio Program explored a number of community design and visioning methods and techniques, reviewed recent case studies from Washington and other states, and based on findings, developed and field tested a recommended framework for community transportation design when state highways serve as main streets. This study finds that for WSDOT projects on state highways that were identified as main streets (inside cities), some scope and schedule adjustments may be avoided by applying a greater degree of community design consideration in systems analysis and project development, resulting in a potential overall savings for the agency.

Authors:
Nicholls,J., Reeves,P.

Keywords:
accident rates

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Abstract:
Greenroads is a performance metric for quantifying sustainable practices associated with roadway design and construction. Sustainability is defined as having seven key components: ecology, equity, economy, extent, expectations, experience and exposure. By Greenroads standards, a sustainable roadway project is one that carefully and overtly integrates these components into the design and construction process to a substantially higher standard than current common practice. Greenroads Version 1.0 consists of 11 Project Requirements, 37 Voluntary Credits (worth 108 points) and up to 10 points worth of Custom Credits. Project-level sustainability performance can be assessed by meeting all Project Requirements and any number of Voluntary Credit points. Greenroads also sets "achievement levels" at different point values in order to provide recommended scoring levels. Greenroads is compatible with other existing systems that can and have been applied to roadways and can be adopted in a number of ways, however the most likely are: (1) as an external standard, (2) as a project accounting standard, and (3) as a tool for competitive advantage for both private industry and public agencies.

Authors:
Muench,S., Anderson,J. L.

Keywords:
accident rates

Abstract:
In the face of many risks of disruptions to our transportation system, this research improves WSDOT’s ability to manage the freight transportation system so that it minimizes the economic consequences of transportation disruptions. This report summarizes 1) the results from a thorough review of resilience literature and resilience practices within enterprises and organizations, 2) the development of a GIS-based statewide freight transportation network model, 3) the collection of detailed data regarding two important industries in Washington state, the distribution of potatoes and diesel fuel, and 4) analysis of the response of these industries to specific disruptions to the state transportation network. The report also includes recommendations for improvements and additions to the GIS model that will further the state’s goals of understanding the relationship between infrastructure availability and economic activity, as well as recommendations for improvements to the statewide freight transportation model so that it can capture additional system complexity.

Authors:
Goodchild,A., Jessup,E., McCormack,E. D., Andreoli,D., Rose,S., Ta,S. R., Pitera,K.

Keywords:
accident rates

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Abstract:
Recent fatigue failures of in-service luminaire support structures in Washington and around the country have prompted concern about their fatigue resistance. Most luminaire support structures in Washington were designed without attention to fatigue or with vague and incomplete fatigue design provisions. Furthermore, most luminaire support structures were installed during the construction of the Interstate system in the 1960s, and as many as half are estimated to have exceeded their 25-year design life. This research was initiated to help the Washington State Department of Transportation (WSDOT) prioritize the inspection and replacement of luminaire support structures throughout the state and to develop rational inspection procedures. The research had four primary components: a literature review, experimental fatigue testing of two in-service luminaire poles, a finite element analysis of the pole base, and development of a framework for estimating remaining life. The extensive literature review found previous experimental studies, which were used to identify details in older WSDOT luminaire support structures that may be critical and to help inform the selection of test specimens. Quasi-static and high cycle fatigue testing were performed on two previously in-service luminaire poles to determine the stress concentration factors (SCF) in critical details and determine fatigue resistance. The results were then compared to the finite element analysis and the fatigue classifications used in design. The finite element model was also used to determine the impact of parameters including base plate thickness, hand hole stiffener thickness, and location of anchor bolts. The individual components of a framework for estimating the remaining life of luminaire support structures in Washington were developed on the basis of a procedure established by Foley et al. (2004) in their study of the remaining life of sign bridge structures. The remaining fatigue life of the critical details in the previously in-service luminaire support structures were found to exceed their design life. Cracking at the stiffened hand hole detail was found to be the ultimate limit state for both specimens but was observed at cycle counts that were well beyond the design life. High SCFs were measured in both compression and tension at the CJP weld toe, indicating the importance of base plate flexibility, anchor bolt layout, and a uniform bearing surface. While it was not possible to know the load history for the selected specimens, it is clear that the number of damaging cycles was low and that the fatigue design life for these details is conservative. Recommendations for luminaire inspection are provided.

Authors:
Frymoyer,M. C., Berman,J. W.

Keywords:
accident rates

Abstract:
Because of undesirable characteristics of some major arterials such as State Route (SR) 99 north and south of Seattle several cities are implementing redevelopment plans. These redevelopment proposals for SR 99 and other state routes include landscaped medians, many with trees placed close to the roadway in either the median or shoulder areas. However, WSDOT’s clear zone width criterion may not always be met when trees are placed within curbed medians. To address this potential conflict, WSDOT chose to adopt an in-service evaluation process that would study collision, environmental, operational, and maintenance experiences in the field. A report was prepared in 2007 that summarized an analysis of two of the 13 median treatment projects. That report also provided before data and condition information on all median sections. This report summarizes the analysis of five additional sections. Because of changes in the methodology, previously reported accident rates were recalculated to be consistent with the after data from this analysis. Data from the before and after periods were also analyzed at two control locations where no median treatments were installed. Total, fatal, fixed object, pedestrian/bicycle, tree, curb/median and U-turn accident rates were analyzed. The percentages of intersection-related, driveway-related, and other accidents were analyzed. Overall, accidents decreased significantly for the treatment locations, but no other types of accidents showed significant changes at either the treatment or the control locations, except for the percentage of other types of accidents at the control locations, which increased significantly. It appears that the installation of landscaped medians does not have a detrimental effect on safety and may result in an overall decrease in accidents, conclusions consistent with those of the first phase.

Authors:
Briglia,P. M., Howard,Z. N., Fishkin,E., Hallenbeck,M. E., St. Martin,A.

Keywords:
accident rates

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Abstract:
This report documents the results of applying a previously developed, standardized approach for evaluating intelligent transportation systems (ITS) projects to 17 ITS earmark projects. The evaluation approach was based on a questionnaire to investigate technical, management, and organizational lessons learned. The report includes 15 evaluation reports for the 17 ITS projects. Each report includes a discussion of the following: • Background • Project description • System usage and benefits • Cost, operations and maintenance • Architecture and standards • Lessons learned. Most of the lessons learned in this evaluation phase were similar to those documented in previous evaluations.

Authors:
Briglia,P. M.

Keywords:
accident rates

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Abstract:
To improve the level of service for Community Transit (CT) buses, the South Snohomish Regional Transit Signal Priority (SS-RTSP) project was launched. To understand the overall benefit of this project, the SS-RTSP system was tested and evaluated after the hardware and software had been installed on the 164th Street SW corridor (Phase One) and the SR 99 corridor (Phase Two) in Snohomish County, Washington State. In this study, impacts of the SS-RTSP system on both transit and local traffic operations were quantitatively evaluated on the basis of field-observed data. Simulation models were also built and calibrated to compute measures of effectiveness that could not be obtained from field-observed data. With simulation models and field observed data, the impacts of the SS-RTSP system on both transit and local traffic operations were quantitatively evaluated. Our evaluation results showed that the SS-RTSP system provided remarkable benefits to transit vehicles, with insignificant negative impacts to local traffic on cross-streets under the current coordinated control strategy. The overall impact of the SS-RTSP system on local traffic at each entire intersection was not statistically significant at the p=0.05 level. To improve the performance of the current SS-RTSP system, more transit vehicles can be made TSP eligible. The average number of granted TSP trips was only 16.96 per day per intersection during the Phase One test and 14.40 during Phase Two test. Given that negative impacts of the SS-RTSP project on local traffic were not significant, more transit trips can be granted with proper TSP treatment to generate more benefits from the SS-RTSP system. Further simulation-based investigations on TSP system operations and optimization were conducted. The research findings indicated that to achieve the best operation efficiency, the compatibility between TSP control schemes and signal control coordination should be strengthened to minimize transit disruption to signal coordination. TSP systems must be fully tested under different coordinated control plans prior to implementation.

Authors:
Wang,Y., Hallenbeck,M. E., Zheng,J., Zhang,G., Corey,J. Ma, X.

Keywords:
accident rates

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Abstract:
Traffic congestion is a major operational problem for freeways in Washington State. Recent studies have estimated that more than 50 percent of freeway congestion is cuased by traffic incidents. To help the Washington State Department of Transportation (WSDOT) identify effective countermeasures against such congestion-inducing incidents, a thorough understanding of travel delays caused by incidents is essential. By using traffic data extracted from archived loop detector measurements and incident log data recorded by the WASOT Incident Response (IR) team, this research project developed a new algorithm for quantifying travel delays produced by different incident categories. The algorithm applies a modified deterministic queuing theory to estimate incident-induced delay by using 1-minute aggregated loop detector data. Incident-induced delay refers to the difference between the total delay and the recurrent travel delay at the time and location influenced by the incident. The uniqueness of the delay calculation in this study is the use of a dynamic traffic-volume-based background profile, which is considered a more accurate representation of prevailing traffic conditions. According to the test results, the proposed algorithm can provide good estimates for incident-induced delay and capture the evolution of freeway traffic flow during incident duration. Because actual traffic data measured by loop detectors were used in this study to compute vehicle arrival and departure rates for delay calculations, the estimated incident-induced delay should be very close to the reality. Additionally, the proposed algorithm was implemented in the Advanced Roadway Incident Analyzer (ARIA) system. ARIA is a database-driven computer system that automates all the computational processes. More accurate incident delay information will help WSDOT improve its understanding of congestion-inducing incidents and select more effective countermeasures against incident-related traffic congestion on freeways.

Authors:
Wang,Y., Cheevarunothai,P., Hallenbeck,M. E.

Keywords:
accident rates

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Abstract:
Two-lane rural highways in Washington State represent approximately 4,900 miles. From 1999 to 2005, 42.8% of the fatal collisions reported on state highways occurred on two-lane rural highways. WSDOT determined that the traditional high collision frequency location approach does not necessarily reflect the safety needs of two-lane rural highways. The research team first conducted a systematic review of the network and then developed a proposed decision-matrix for the selection of countermeasures on two-lane rural highways. A rate-based approach was used to show various trends across different user groups, geometric features, and contexts. It is generally accepted that the context of the two-lane rural highway would influence countermeasure choice. The project tested two contextual surrogates for the identification of particular two-ane rural highways that may exhibit safety characteristics that are different from the rest of the network. First proximity to K12 schools (in half mile increments up to 2 miles) was tested to determine whether it could assist in identifying more developed areas, such as rural town centers. It showed promise and identified areas with lower collision severity but higher collision frequency along with a higher incidence of pedestrial related collisions. Second proximity to urban boundaries (increments up to 2 miles) as means to identify transition areas showed less promise. The decision-matrix summarizes countermeasure effectiveness by collision group and also makes reference to the findings from the systematic assessment. The project also included a limited before-after study of centerline rumble strip installations (CLRS). Although results indicate some benefits and possible collision increases, caution is noted in terms of application of these findings because of small sample sizes in the analysis and the fact that roadside characteristics could not be incorporated in the evaluation process. The report recommends the development of safety performance functions that would incorporate these features. These multivariate approaches could further assist the department in the development of system-wide and corridor level approaches for two-lane rural highways.

Authors:
Van Schalkwyk,I., Washington,S. P.

Keywords:
accident rates

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Authors:
Thom,R., Gaeckle,J., Borde,A., Anderson,M., Boyle,M., Durance,C., Kyte,M., Schlenger,P., Stutes,J., Weitkamp,D., Wylie-Echeverria,S., Rumrill,S.

Keywords:
accident rates

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The use of a few large-diameter reinforcing bars for the construction of precast concrete bridge bents allows simplified construction by reducing the number of alignments to be made in the field. These bars are grouted into ducts in a precast concrete cap beam. In the proposed precast concrete substructure system, the grouted bars carry tensile forces across the joint between the column and cap beam. This joint is the yielding element in the structural system, and it is crucial to the performance of the structure that the bars yield before other failure mechanisms, including bond failure, occur. However, the cap beam is typically insufficient to anchor the bar, as the depth of the beam is substantially less than the American Association of State Highway and Transportation Officials (AASHTO) bridge code allows. For this project, 17 pullout tests were conducted to determine the bond characteristics and development length of large-diameter bars grouted into ducts. The bars tested ranged in size from #8 to #18. Pullout tests conducted with embedment lengths of at least six bar diameters yielded the reinforcing bar, while the test conducted with an embedment length of 14 bar diameters resulted in bar fracture. The tests and subsequent analysis showed that the bond of these grouted connections is significantly better than the bond of bars cast directly into concrete. The development lengths needed to fully anchor the bar are therefore within the depth available in the cap beam.

Authors:
Steuk,K. P., Pang,J. B., Eberhard,M. O., Stanton,J. F.

Keywords:
accident rates

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Abstract:
An experimental application of NovaChip was evaluated on a section of SR-17 through the city of Soap Lake, Washington. NovaChip was investigated as a possible substitute for HMA Class G that is normally specified through cities on routes that only warrant a bituminous surface treatment. The NovaChip was placed in the summer of 2001. Pavement condition survey results and visual observations revealed that Novachip was effective in reducing both the frequency and severity of cracking. Ride quality has remained constant throughout the six year evaluation period and wear/rutting has been minimal. Life cycle cost analysis showed that NovaChip is comparable to HMA Class G when analyzed on a total project cost basis, but not competitive when only the cost of the overlay is considered.

Authors:
Russell,M. A., Pierce,L. M., Uhlmeyer,J. S., Anderson,K. W.

Keywords:
accident rates

Abstract:
Approximately 3,000 deer and 85 elk carcasses are removed by WSDOT personnel from Washington State highways annually. The report provides an analysis of temporal and spatial relationships associated with carcass removal sites. Models were developed to assess influences of road characteristics, habitate features, deer densities, and deer behavior to frequency of vehicle collisions at carcass removel sites.

Authors:
Meyers,W. L., Chang,W. Y., Germaine,S. S., Vander Haegen,W. M., Owens,T. E.

Keywords:
accident rates

Abstract:
The objectives of this study are three-fold: (1) develop/validate dynamic numerical finite element models to simulate the prestressed concrete bridge girders with intermediate diaphragms, (2) perform numerical parametric study to evaluate the effect of the critical factors on design of intermediate diaphragms, and (3) provide recommendations and guideline to better design of intermediate diaphragms to impact of over-height trucks. The conducted study aims to shed light on improved impact protection of prestressed concrete bridge girders with intermediate diaphragms and aid the WSDOT in design, analysis, and consstruction of prestressed concrete bridges. The findings of this study assist in developing the specific standard of practice (such as, amendments to AASHTO standard specifications, WSDOT standard specifications, policy directives, implementation manuals, or operating procedures) for design of prestressed concrete bridge girders with intermediate diaphragms. More importantly, the proposed recommendations and guideline help the bridge engineers to make better design decision for prestressed concrete bridges.

Authors:
McLean,D. I., Qiao,P., Yang,M.

Keywords:
accident rates

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Abstract:
Small, unmanned aerial vehicles (UAVs) are increasingly affordable, easy to transport and launch, and can be equipped with cameras that provide information usable for transportation agencies. The Washington State Department of Transportation conducted a series of UAV tests to evaluate their capabilities while also exploring institutional issues. These tests, while exploring the general capabilities of UAVs, focused on evaluating the use of a UAV as an avalanche control tool on mountain slopes above state highways. WSDOT’s maintenance division has an active snow avalanche control program that is designed to reduce highway closure time and hazards to motorists, and the use of UAVs was seen as having some potential operational advantages. The UAVs also captured aerial images suitable for traffic surveillance and data collection. The evaluation found that the main limitation to UAV use is institutional, particularly the need to obtain approval to fly from the Federal Aviation Administration (FAA). This approval process will make UAV use a challenge, but these issues may change as the FAA considers new rules. 17.

Authors:
McCormack,E. D.

Keywords:
accident rates

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Abstract:
This study looked at the performance of quieter pavements in use in the United States of America and Europe with specific emphasis on those states that are using open-graded mixes for both friction or porous courses on an ongoing basis. All states were contacted and 34 states responded with information on their use of open-graded mixes and stone matrix asphalt (SMA) mixes. Eleven states were able to provide an estimate of the range and average service life of their open-graded mixes and three states provided information on the service life of their SMA mixes. Specifications for open-graded mixes and SMA mixes were compiled from 20 states and compared to Washington State's open-graded friction course mix and the open-graded mix used on recent test sections built by the Washington State Department of Transportation

Authors:
Jackson,N. C., Vargas,A., Pucinelli,J.

Keywords:
accident rates

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Abstract:
This report examines pedestrian and motorist behavior on arterials in Washington State and determines how, if at all, these behaviors change when various engineering treatments are applied. The treatments that were examined included crosswalk markings, raised medians, in-pavement flashers, signage, stop bars, overhead lighting, and sidewalks. The relationships between pedestrian travel and transit use, origin-destination patterns, traffic signals, and schools were also explored. The study examined seven locations in the state of Washington. These were State Route (SR) 7 at South 180th Street in Spanaway, SR 99 at South 152nd Street in Shoreline, SR 99 at South 240th Street in Kent, SR 2 between South Lundstrom and King Streets in Airway Heights, SR 2 at Lacrosse Street in Spokane, SR 2 at Rowan Avenue in Spokane, and SR 2 at Wellesley Avenue in Spokane. Because pedestrian-vehicle collisions are rare when specific locations are studied, other criteria were used to evaluate the conditions and behaviors that were present. These included "conflicts" such as running behavior, motorists having to brake unexpectedly to avoid a pedestrian, pedestrians waiting in the center lane to cross, and more. These unreported, but very common, occurrences enabled the researchers to gain a better understanding of both pedestrian and motorist concerns and behaviors and the effects that improvements might have. The study concludes that the causes of conflicts are highly varied: ignorance of or noncompliance with the law (by the motorist or the pedestrian), inattention, vehicles following too closely, impatience, anxiety in attempting to catch a bus, use or non-use of pedestrian facilities, placement of features in the built environment, and more. While pedestrian/motorist interaction improves with improved visibility (something which can be obtained through better engineering design and the removal of visual clutter) better education and/or enforcement will also be needed to achieve significant safety benefits.

Authors:
Davis,K., Hallenbeck,M. E.

Keywords:
accident rates

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Abstract:
The TRACFLOW software processes induction loop data to develop performance metrics for freeways in the Seattle area. The loop data are sometimes subject to errors. To find and correct errors, the TRACFLOW system uses a three-step approach to detect and address variations in the quality of the traffic data. Each step can include data replacement if sufficient supporting data are present. This combination of methods is automated whenever feasible to more efficiently handle the large data sets involved. This report describes the three steps, detailing how each contributes to cleaner and more robust data sets. The objectives of these methods are to detect a higher percentage of anomalous data points, replace them with higher quality values, enable more of the data to be used, and increase overall automation of the process.

Authors:
Wright,D., Ishimaru,J. M.

Keywords:
accident rates

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Authors:
Vernez-Moudon,A., Hallenbeck,M. E., Hoag,A., Sohn,D. W., Park,S.

Keywords:
accident rates

Abstract:
The purpose of this study was to determine what hydraulic characteristics enhance or diminish upstream juvenile salmon passage within a sloped-weir baffled culvert. The culvert slope, baffle spacing and baffle height were varied to observe flow regime trends that describe conditions suitable for fish passage. Biological testing was conducted in conjunction with the hydraulic micro-Acoustic Doppler Velocimeter (ADV) measurements. There was considerable spatial variability in the flow created by the sloped baffles within the culvert. The asymmetry of flow (A), decreased for increasing discharge, larger baffle spacing and smaller baffle heights. To describe the flow features essential to fish passage, the interrelation between flow asymmetry, depth, and velocity were presented in comparison with biological testing. For the range of parameters tested, flows were described by a series of three jet regimes which were a function of water depth over baffles. Comparing these regimes to the biological study revealed peak juvenile salmon passage was associated with a critical transition between jet regions. Generalizing this transition for the entire data set using dimensionless scales provides professionals with guidance for retrofitting culverts.

Authors:
Thurman,D. R., Horner-Devine,A. R.

Keywords:
accident rates

Abstract:
A database of dynamic modulus values for typical Superpave mixes widely used in the state of Washington was developed and used to investigate the sensitivity of the dynamic modulus to aggregate gradation. Seven JMF mixes were selected for the study. Percent passing sieve #200 of these mixes were changed by ± 2% to prepare additional mixes referred to as ‘modified mixes’. Statistical analysis showed that using different JMF mixes significantly affected the dynamic modulus. This was not the case when modifying the JMF by changing the percent passing #200. A simple evaluation of the prediction accuracy of the 2002 Mechanistic-Empirical Pavement Design Guide (MEPDG) was conducted in which the measured dynamic modulus was used as a key input parameter to predict pavement distresses. Level 1 and Level 3 predictions of rutting, longitudinal cracking, alligator cracking, and IRI were compared with the field performance data. The Design Guide predicted IRI and alligator cracking reasonably well. The predicted rutting of the JMF mixes agreed well with the dynamic modulus trend. It was found that the ±2% change in the passing #200 aggregate gradation did not affect the predicted distress significantly.

Authors:
Tashman,L., Elangovan,M. A.

Keywords:
accident rates

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Abstract:
Arterials such as State Route (SR) 99 north and south of Seattle have characteristics that are considered by many cities to be undesirable. In response, several cities are implementing redevelopment plans to increase road safety, create a more aesthetically pleasing local environment, and enhance the economic vitality and attractiveness of the communities. The cities’ redevelopment proposals for SR 99 and other state routes include landscaped medians, many with trees placed close to the roadway in either the median or shoulder areas. However, WSDOT’s clear zone width criterion may not always be met when trees are placed within curbed medians. To address the desires of cities to implement aesthetic designs, WSDOT chose to adopt an in-service evaluation process that would study collision, environmental, operational, and maintenance experiences in the field. This report summarizes the findings of two of the 13 median treatment projects included in the in-service evaluation of alternative median treatments. It provides before data and condition information on all median sections, but because most of the roadway sections have only recently been improved, it provides after data for only two phases of improvements, those on SR 99 in the City of SeaTac. The conclusions of the before and after analysis on those two sections of roadway indicate that no dramatic changes in roadway safety have occurred as a result of the change from continuous two-way left turn lanes and limited sidewalks to a streetscape that includes full sidewalks and landscaped medians with turn pockets, and where both sidewalks and medians include small trees as part of the landscaping. While no definitive conclusions about the safety impacts of landscaped medians can be drawn at this point in the multi-year in-service evaluation, it can be said that there is no indication that the roadways are less safe than before the landscaping was planted. Therefore, it is recommended that the current in-service evaluation be continued as planned.

Authors:
St.Martin,A., Hallenbeck,M. E., Milton,J., Nee,J.

Keywords:
accident rates

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Abstract:
Arterials such as State Route (SR) 99 north and south of Seattle have characteristics that are considered by many cities to be undesirable. In response, several cities are implementing redevelopment plans to increase the safety of the road, create a more aesthetically pleasing local environment, and enhance the economic vitality and attractiveness of the communities. The cities' redevelopment proposals for SR 99 and other state routes include landscaped medians, many with trees placed close to the roadway in either the median or shoulder areas. However, WSDOT's clear zone width criterion may not always be met when trees are placed within curbed medians. To address the desires of cities to implement aesthetic designs, WSDOT chose to adopt an in-service evaluation process that would study collision, environmental, operational and maintenance experiences in the field. This report summarizes the findings of two of the 13 median treatment projects included in the in-service evaluation of alternative median treatments. It provides before data and condition information on all median sections, but because most of the roadway sections have only recently been improved, it provides after data for only two phases of improvements, those on SR 99 in the City of SeaTac. The conclusions of the before and after analysis on those two sections of roadway indicate that no dramatic changes in roadway safety have occurred as a result of the change from continuous two-way left turn lanes and limited sidewalks to a streetscape that includes full sidewalks and landscaped medians with turn pockets, and where both sidewalks and medians include small trees as part of the landscaping. While no definitive conclusions about the safety impacts of landscaped medians can be drawn at this point in the multi-year in-service evaluation, it can be said that there is no indication that the roadways are less safe than before the landscaping was planted. Therefore, it is recommended that the current in-service evaluation be continued as planned.

Authors:
St. Martin,A., Milton,J., Hallenbeck,M. E., Nee,J.

Keywords:
Trees, highway safety, aesthetic design, Context Sensitive design, urban design, accident rates, injury severity

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Abstract:
Research over the last decade has shown that pulse-type earthquake ground motions that result from forward-directivity (FD) effects can result in significant damage to structures. Three typical post-1990 Washington State Department of Transportation (WSDOT) monolithic concrete bridges were chosen to investigate their nonlinear response to FD ground motions (FDGMs) and non-FDGMs. Results showed that significant seismic damage may occur if the structural response is in tune with the period of the velocity pulse of the FDGM. This velocity pulse is a result of fault propagation effects in the near-fault, and occurs when the direction of slip and rupture propagation coincide. The period of the velocity pulse is proportional to the magnitude of the earthquake. the severity of the damand is controlled by the ratio of the pulse period to bridge fundamental periods. As a consequence of this, damage in a bridge with moderate periods (T=0.1s to 1.0s) may be more significant in smaller magnitude earthquakes where the pulse period is closer to the fundamental period of the structure. This was the case for both the MDOF and SDOF analyses of all three bridges in this research. The results showed also that the occurrence of high PGA and/or PGV is only one of several conditions that can cause high demand on the bridges. Of the three bridges considered, all typical concrete overpasses ranging from 50 m to 91 m in length, all generally survived the earthquake motions with only minor damage to their columns. However, colemn flexural failure was predicted for one model when subjected to two of the forward directivity ground motions. SDOF bridge models for preliminary analyses were found to yield slightly unconservative base shears and displacements compared to that of the full bridge models under non-FDGM. For FDGM, the results of a simple SDOF bridge model ranged from very conservative to slightly unconservative. Therefore, nonlinear SDOF analyses are specifically not recomnended in the case of FDGM since the results were not consistent. A more detailed MDOF model should be used to assess bridge seismic performance so that SSI and the interaction of the longitudinal and transverse responses of the bridges can be included, particularly if a performance based design or assessment of the bridge is required.

Authors:
Rodriguez-Marek,A., Cofer,W. F.

Keywords:
accident rates

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Abstract:
The study provides the Washington State Department of Transportation (WSDOT) with an estimate of the current and future use of roadways and transload facilities in Washington by Washington's forest products sector. Estimates of current and projected future use by wood product manufacturers will allow the WSDOT to better plan its infrastructural needs to move products across the state efficiently.

Authors:
Perez-Garcia,J.

Keywords:
accident rates

Abstract:
This report provides data from the biological tests conducted in December 2004 and January 2005 by Battelle Pacific Northwest Division for the Washington State Department of Transportation at the Culvert Test Bed located at the Washington State Department of Fish and Wildlife Skookumchuck Hatchery near Tenino, WA. The work reported here aimed to determine the leaping ability of juvenile hatchery coho salmon as the fish entered a perched culvert. Results of the trials showed that the entry rate and passage success decreased as outfall drop increased. The dominant behavior used to accomplish entry varied with outfall drop. When overcoming the 0-cm and 12-cm outfall-drop configurations, juvenile coho predominantly used swim-in behavior. For the greater outfall drops of 20 and 26 cm, juvenile coho used leaping behavior for culvert entry. Juvenile coho were not able to successfully overcome the 32-cm outfall drop, which was equivalent to approximately 3 body lengths for the 100-mm coho tested in this study

Authors:
Pearson,W. H., Mueller,R. P., Sargeant,S. L., May,L. K.

Keywords:
accident rates

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Abstract:
To address the need to deliver cost-effective projects while minimizing traffic impacts, the Washington State Department of Transportation (WSDOT) desires to improve their knowledge, awareness and retention of rapid pavement construction tools, materials and methods. This project discusses the implementation, use and experience of using the following items related to rapid pavement construction: CA4PRS (Construction Alternatives for Pavement Rehabilitation Strategies), portland cement concrete (PCC) pavement panel replacement, polymer concrete and traffic closure windows. CA4PRS is a Microsoft Access-based software program for predicting construction productivity for highway rehabilitation/reconstruction. It was tested in two case studies and has proved capable of providing meaningful scheduling and productivity inputs into early project planning. Panel replacement techniques and polymer concrete construction are reviewed (including contractor interviews) in an effort to document past successes and failures as well as key decision points when making future project decisions. Finally, a review of traffic closure windows for rapid construction is presented.

Authors:
Ozolin,B., Muench,S.

Keywords:
accident rates

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Authors:
Nee,J., Hallenbeck,M. E.

Keywords:
accident rates

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Authors:
Mason,R. M.

Keywords:
accident rates

Abstract:
The Interstate 5 portland cement concrete pavement (PCCP) in King County has been in service for over 40 years, twice its planned design life. As such, I-5 is in need of a rehabilitation/reconstruction effort. This study provides WSDOT information that will aid decision making about the timing, locations, and type of rehabilitation or reconstruction. Extensive pavement conditions/distress data provided by WSDOT were summarized, analyzed, and used to develop visual tools to communicate the condition of the I-5 PCCP. The performances of the non-rehabilitated, diamond ground, and the dowel bar retrofit and diamond ground PCCP were summarized and compared. Use of such information shows that about 66 percent of I-5 in King County is in need of rehabilitation or reconstruction. To further illustrate these conditions, Arc GIS was used to map the various distresses/conditions, and the results suggest which sections of I-5 should be addressed early in the rehabilitation/reconstruction process. The report concludes with a broad assessment of expected I-5 conditions and necessary WSDOT actions for five-year increments (0 to 5 years, 5 to 10 years, and greater than 10 years).

Authors:
Mahoney,J. P., Hansen,M. A., Jackson,N. C., Hunter,C. A., Pierce,L. M.

Keywords:
accident rates

Abstract:
This report describes the results of a detailed investigation of improved procedures for evaluation of liquefaction hazards in Washington State, and describes the development and use of a computer program, WSliq, that allows rapid and convenient performance of improved analyses. The report introduces performance-based earthquake engineering (PBEE) concepts to liquefaction hazard evaluation. PBEE procedures have been developed and implemented for evaluation of liquefaction potential, lateral spreading displacement, and post-liquefaction settlement. A new model for estimation of the residual strength of liquefied soil was also developed. The WSliq code was developed to have broad capabilities for evaluation of liquefaction susceptibility, liquefaction potential, and the effects of liquefaction. It provides new methods for dealing with the magnitude-dependence inherent in current procedures, and makes the common “magnitude selection” problem moot via a new multiple-scenario approach and through the use of PBEE procedures.

Authors:
Kramer,S. L.

Keywords:
accident rates

Abstract:
This document is a guide to developing documentation for microscopic traffic simulation models developed for the Washington State Department of Transportation (WSDOT) by using the VISSIM simulation environment. Model documentation produced according to the guidelines in this document are designed to assist prospective project managers and model users in determining whether the associated model meets their analytical needs, as well as assisting future simulation model users/analysts who consider modifying or expanding the model. This guide provides a procedure for the development of VISSIM model documentation that reflects key elements of the model, including objectives, inputs, and functional components; describes the format, topics, and level of detail of the resulting documentation; and outlines a documentation methodology that does not require an unreasonable amount of time and effort.

Authors:
Ishimaru,J. M., Hallenbeck,M. E., Beaulieu,M., Davis,K., Kieninger,D., Mizuta,K., Robinson-McCutchen,E., Wright,D., Wright,D.

Keywords:
accident rates

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Abstract:
The Interstate 5 portland cement concrete pavement (PCCP) in King County has been in service for over 40 years, twice its planned design life. As such, I-5 is in need of a rehabilitation/reconstruction effort. This study provides WSDOT information that will aid decision making about the timing, locations, and type of rehabilitation or reconstruction. Extensive pavement conditions/distress data provided by WSDOT were summarized, analyzed, and used to develop visual tools to communicate the condition of the I-5 PCCP. The performances of the non-rehabilitated, diamond ground, and the dowel bar retrofit and diamond ground PCCP were summarized and compared. Use of such information shows that about 66 percent of I-5 in King County is in need of rehabilitation or reconstruction. To further illustrate these conditions, Arc GIS was used to map the various distresses/conditions, and the results suggest which sections of I-5 should be addressed early in the rehabilitation/reconstruction process. A field study assessing the I-5 PCCP was conducted at the same location as a 1986 study, providing a unique opportunity to compare the PCCP conditions over a span of 20 years. The field study showed that the number of cracks had more than doubled, spalling dimensions had increased, and faulting displacements had increased by more than 43 percent. The report concludes with a broad assessment of expected I-5 conditions and necessary WSDOT actions for five-year increments (0 to 5 years, 5 to 10 years and greater than 10 years).

Authors:
Hansen,M. A., Mahoney,J. P., Jackson,N. C., Hunter,C., Pierce,L. M.

Keywords:
accident rates

Abstract:
The primary objectives of this project were to analyze the potential of a hypothesis regarding the ability of traffic data from basic loop sensors to represent approximate arterial traffic conditions (congestion); to develop a prototype analytical method to implement that relationship, and to determine requirements and other issues associated with future application of the method. The hypothesis being tested was that there is a general relationship between 1) the data from an arterial loop sensor, and b) the overall level of congestion on the arterial segment near the loop for that direction of travel. Specifically, lane occupancy percentage values from a loop sensor located just upstream from a stop bar for an arterial traffic signal were hypothesized to be a surrogate value for nearby arterial performance (specifically, congestion on traffic delay), and this relationship was proposed to be used to develop a basic arterial performance monitoring method to aid in planning and operational analyses, as well asl potential real-time monitoring applications such as online traffic maps. This research provided additional understanding of the feasibility of using basic sensor data to monitor performance on arterials, as well as outstanding issues. Given the results thus far, the use of green-plus-amber occupancy values from a stop bar loop shows the most promise among the options analyzed; furthermore, the hardware and analytical requirements are not restrictive. There is a need for additional testing of the robustness of this method before it can be implemented.

Authors:
Hallenbeck,M. E., Ishimaru,J. M., Davis,K. D., Kang,J. M.

Keywords:
accident rates

Abstract:
The transportation system in the Puget Sound region is in crisis. Regional transportation infrastructure and services are not keeping pace with population, employment, and travel demand growth. This gap is widening because our current transportation finance system—both statewide and within the region—is not generating enough revenue to repair and replace aging facilities, let alone add the capacity needed to meet current and projected demands. Over the next 20 years, the state faces in the neighborhood of $80 billion in transportation needs. The Puget Sound region accounts for approximately $40 billion of that total. King County’s share alone equals roughly $30 billion. Within the Puget Sound region, even if all of the proposed funding packages pass this November, we will be well short of the funds needed to meet these needs.

Authors:
Hallenbeck,M. E.

Keywords:
accident rates

Abstract:
Service times at vehicle processing facilities (borders, weigh stations, landside marine port gates) are variable, thereby causing transportation planning challenges for companies that regularly visit them on a regular basis.  Companies must either build in more time than is necessary, therefore underutilizing their equipment or risk missing delivery windows, which can incur fines or cause lost business opportunities.  In this study, we examine border crossing times at Blaine, Washington between Whatcom county, Washington and the lower Mainland of British Columbia.  We consider the the variability in crossing times at this border crossing, and the impact of this variability on regional supply chains.  We present variability data collected for bi-directional trade.  directional, daily, hourly, and seasonal variations are examined.  We conducted interviews with regional carriers to better understand the current response to variability, the benefit of a reduction in variability, and how this is related to the goods moved or to other business operatiing characteristics.  This paper describes the level of variability in border crossing times and describes carriers' responses to this variability.   We show that the primaryt strategy used, increasing buffer times, reduces carrier productivity.  However, this cost is negligible due to the current nature of the market.

Authors:
Goodchild,A., Globerman,S., Albrecht,S.

Keywords:
accident rates

Abstract:
Service times at vehicle processing facilities (borders, weigh stations, landside marine port gates) are variable, thereby causing transportation planning challenges for carriers that visit them on a regular basis. Carriers must either build in more time than is necessary, therefore underutilizing their equipment, or risk missing delivery windows, which can result in fines or cause lost business opportunities. In this study, border crossing times at Blaine, Washington, are examined. The variability in crossing times at this border crossing, and the impact of this variability on regional supply chains is considered for bi-directional trade. Directional, daily, hourly, and seasonal variations are examined. Interviews with regional carriers were conducted to better understand the current response to variability, the benefit of a reduction in variability, and how this is related to the goods moved or to other business operating characteristics. This paper describes the level of variability in border crossing times and describes carriers’ responses to this variability. It is demonstrated that the primary strategy used, increasing buffer times, reduces carrier productivity. However, this cost is negligible due to the current nature of the market.

Authors:
Goodchild,A., Globerman,S., Albrecht,S.

Keywords:
accident rates

Abstract:
This research focused on developing reliability-based seismic retrofit assessment procedures for highway bridge columns. Fragility curves were developed to assess the relative performance of various retrofit methods considering several limit states. Analytical fragility curves are developed from scaled earthquake records and structural response models. A simplified, single-degree-of-freedom (SDOF) structural model was assumed to reasonably represent the structural response of the bridge columns for this research. The structural configuration, geometry, and properties of the bridge columns came from Washington State Department of Transportation standard bridge designs. Scaled earthquake data were used to calculate the displacement history during the prescribed earthquakes, and structural displacement, ductility and dissipated energy, were determined to calculate damage indices (DI). Various retrofit methods were selected from the literature. For the retrofitted cases, different degrees of increase in mass, stiffness, damping, and ductility were taken from the literature, over those of the un-retrofitted structure.

Authors:
Fridley,K. J., Ma,Z.

Keywords:
accident rates

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Abstract:
This study on the angle of gyration for Superpave compactors was done to determine if there is a difference in the bulk specific gravity (Gmb) – and ultimately the volumetric properties – when calibrating the compactor’s angle of gyration internally and externally. WSDOT currently has Troxler, Pine, Pine-Brovold, and Interlaken compactors across the state, so a representative sample (two to four compactors per region) was tested in this study. Triplicate samples of hot-mix asphalt (HMA) were used for each compactor. It was found that 41 percent of the compactors tested were not in specification when using the internal angle to calibrate the compactor. Adjustments were made to those compactors and the bulk specific gravity results were compared. The results of the bulk specific gravity affect the volumetric properties of HMA (Va, VMA, and VFA) and therefore can have an affect on the design and acceptance of HMA. When calibrating the compactors via external angle (current AASHTO standard), the average air voids (target of 4.0) were 3.81 with a standard deviation of 0.54. When calibrating via internal angle, the average air voids were 3.98 with a standard deviation of 0.50. Based on the results of this study, WSDOT is working to: (1) evaluate additional gyratory compactors (both WSDOT- and Contractor-owned), (2) make changes to current verification/calibration procedures, and (3) implement the use of the internal angle of calibration for 2008.

Authors:
DeVol,J., Krause,J., McLaughlin,S., Willoughby,K., McLean,I.

Keywords:
accident rates

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In this brief report, we provide a description of the activities in each of the areas to which the Backbone contributes, and we provide supporting statistics for each of these contributions. The form of these statistics varies by application area: (1) potential viewers, in the case of TrafficTV, (2) page views, in the case of MyBus, (3) data stream use, in the case of Busview, (4) number of downloads, in the case of the Self Describing Data (SDD) Toolkit and, (5) use of the Web services. The ITS Backbone has been financially supported by WSDOT to provide a level playing field to distribute detailed real-time and historical data to the public, private, and research sectors.

Authors:
Dailey,D. J.

Keywords:
accident rates

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The overall goal of this research project was to investigate ways to accurately scope projects with an efficient process in a timely manner to align with the critical path development for programming and the legislative cycle. The need for improved cost estimation is an acknowledged essential element in the scoping of a project. Past experiences throughout the world reveal how common and problematic these underestimations of cost and schedules, especially for mega-projects, have become. The accompanying public distrust, lack of confidence in project implementers, and lack of interest in increased funding have generated a great deal of literature, studies, website activity and media attention. In this research effort, much of the many volumes of material on the subject of scoping and cost escalation were reviewed. Selected findings from selected differing sources formed the core of the review of literature section. These findings were then augmented by a broad survey and review of the activities and efforts of various states, usually by the Departments of Transportation in those states. Those discussions and analyses of those activities allow specific findings and recomendations to be determined

Authors:
Casavant,K. L., Jessup,E., Holmgren,M.

Keywords:
accident rates

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This study identified freight data uses, needs and gaps, both nationally and in the State of Washington. Specific recommendations for providing the needed data and data generating processes include the following: - Phase I: Identification of Data Gaps, Needs, and Uses (Timeframe: current and ongoing) An ongoing inventory of available freight data, relative to identified freight data needs, should be performed throughout the state and region. This process may be incorporated into the expected activities/duties proposed in these recommendations. - Phase II: Librarian/Educator, Resource to Manage Freight Data Warehouse (Timeframe: within six months). This individual or resources is a "data source" for the state; a contact for all agencies and businesses using transportation flow and operational data; and a participant in discussions as freight data needs arise in the state. - Phase III: Freight Database Manager, Technical Resource (Timeframe: within one year). The Freight Database Manager will design/develop and maintain the freight data warehouse for the Washington State Department of Transportation (WSDOT)

Authors:
Casavant,K. L., Jessup,E.

Keywords:
accident rates

Abstract:
Under contract to the Washington State Department of Transportation, Battelle, Pacific Northwest Division, conducted a re-analysis of dynamic pile driving and impulsive underwater sound data acquired at WA DOT construction projects (Hood Canal Bridge and Friday Harbor Ferry Terminal) to better understand the mechanisms of impulsive sound generation by pile driving in support of efforts to determine the effects of impulsive sound on fish health and behavior. Analysis focused on derivation of statistics from impulsive sound and dynamic pile driving data sets that permitted evaluation of the amount of variability in impulsive sound metrics that might be driven by variability in pile driving mechanics metrics. The energy required to drive a pile at various depths and substrates and an index of the sound energy produced during the pile drives were also compared. These comparisons yielded the conclusion that most of the variability in impulsive sound during driving of a pile can be accounted for by changes the impact hammer operator makes to overcome resistance to increases in pile depth. Thus, it is the operation of an impact hammer in response to changes in substrate, not the substrate itself, that is responsible for the changes in impulsive energy metrics during driving of a pile. A recommendation of the study is that any future data acquisition and analysis efforts to improve understanding of linkages between pile driving mechanics and impulsive sound or underwater sound monitoring activities in support of construction activities include hammer stroke data as a basic element of underwater sound data sets.

Authors:
Carlson,T. J., Weiland,M. A.

Keywords:
accident rates

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Considerable portions (as much as 25% by some estimates) of commute time auto trips are taking students to school. This study seeks to learn what strategies can reduce and are reducing auto congestion around schools. Phase 1 of the study includes a literature review summarizing the state of knowledge about the subject and helping to identify models and strategies. These include ride sharing clearing houses, supervised walking to school programs, carpooling, safe routes to schools programs, bicycling and mobility education, school siting policies and requirements, and the use of yellow school buses and public transit. These models guided the search for potential programs of interest in Washington state to examine and learn from in Phase 2 of the study. These programs of interest include safe routes to schools programs in urban and small city elementary schools, the use of fare-free transit, introduction of mobility education curriculum in high schools, a mandatory universal pass program at a university, a ride sharing website, and inclusion of a school in a growth and transportation efficiency center under the state’s Commute Trip Reduction law.

Authors:
Carlson,D., Langworthy,M., Wright,J., Gruen,D.

Keywords:
accident rates

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Abstract:
The performance of portland cement concrete mixes with higher flexural strength, higher cement content, and with Hard-Cem additive and carpet drag finish will be evaluated over a period of five years to determine if they are more resistant to studded tire wear. Special sections of each mix will be tested over a five year period to determine the rate of studded tire wear as compared to the WSDOT standard 650 psi flexural strength mix and tined finish. In addition, the carpet drag finish will be compared to transverse tining with regard to providing adequate friction resistance over time and reducing tire/pavement noise.

Authors:
Anderson,K. W., Uhlmeyer,J., Pierce,L.

Keywords:
accident rates

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Abstract:
Two sections of pavement were built with different specifications for the gradation of the aggregates, one with the standard WSDOT specification and one with a combined gradation, to determine if the use of the combined gradation would result in a pavement more resistant to studded tire wear. The standard gradation can result in a gap-graded aggregate whereas the combined gradation produces a more uniform gradation. Wear rates calculated for the most recent data set collected in the fall of 2006 reveals no difference in wear rates between the pavements paved with the standard gradation versus those paved with the combined gradation.

Authors:
Anderson,K. W., Uhlmeyer,J., Pierce,L.

Keywords:
accident rates

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Abstract:
This report describes the construction of a portland cement concrete pavement built with three finishing methods; carpet drag, longitudinal tining, and transverse tining. The three finishing methods will be compared for their ability to resist the wear from studded tires. Ride and friction resistance will also be monitored and reported over the five year evaluation period.

Authors:
Anderson,K. W., Uhlmeyer,J., Pierce,L.

Keywords:
accident rates

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A Skidabrader machine was used to remove the corduroy texture of a section of PCCP on Interstate 5 in Seattle Washington. The corduroy texture of the pavement was the product of a previous diamond grinding operation that improved the ride quality and restored the transverse profile of the pavement.

Authors:
Anderson,K. W., Uhlmeyer,J., Pierce,L.

Keywords:
accident rates

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Abstract:
Increased environmental awareness and stricter emissions regulations have led to a development of warm mix asphalt (WMA) to reduce the high mixing temperatures of regular hot mix asphalt (HMA). Its benefits are reduction in energy consumption during production and reduced emissions during production and placement. The three most tested methods are; WAM Foam, Aspha-min zeolite and Sasobit wax. All three methods reduce the viscosity of the binder at a certain temperature range, allowing the aggregate to be fully coated at lower temperatures than in HMA production. Previous research has not focused much on how WMA functions in cold weather paving. This paper investigates WMA’s potential in cold weather conditions and specifically how Iceland, with such conditions, can benefit from it. The conclusions in this paper are drawn from a literature review and a survey that was conducted among Iceland’s paving industry professionals. Reduced emissions are especially beneficial in densely populated areas and in non-open air paving. The decreased viscosity allows effective compaction at lower temperatures where cool down rates are slower. WMA’s disadvantages are mainly related to rutting and moisture susceptibility issues. Using WMA processes at HMA production temperatures: 1) Increases the temperature gap between production and cessation, allowing e.g. increased haul distances 2) Facilitates compaction, which is beneficial for; stiff mixes and RAP, paving during extreme weather conditions and reduction in compaction effort. Icelandic professionals are generally positive towards WMA, interested in testing it further for Icelandic conditions, and hopeful about its potential for helping with some key problems in Icelandic paving. The final conclusion is that WMA is a viable option for cold weather conditions and for the paving industry in Iceland, Sasobit is most suitable of the three methods, and usage incentives are twofold: 1) As a compaction aid for mixes produced at, or close to, regular HMA production temperatures, used to increase haul distances and/or pave during cold and difficult weather conditions, and sometimes slightly reduce fuel consumption as well. 2) As an environmentally friendly method when emissions approach limits, although not an issue today it may become one with stricter emissions regulations or increased production.

Authors:
Kristjansdottir,O.

Keywords:
accident rates

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The Growth Management Act (GMA) introduced the idea of “concurrency,” the policy goal of ensuring that development not outpace the provision of infrastructure. The GMA directs jurisdictions to define and establish level of service (LOS) standards for their transportation systems. If new development will cause the transportation system to exceed the established LOS standards, the jurisdiction must deny the development unless transportation improvements and strategies are implemented to accommodate the development within six years, a process known as concurrency mitigation.

Authors:
Hallenbeck,M. E., Carlson,D., Ganey,K., Vernez-Moudon,A., Steiner,R.

Keywords:
accident rates

Abstract:
This report documents the construction of a section of Portland cement concrete pavement on I-5 in the vicinity of Federal Way, Washington. The project included the use of a carpet drag finish on the PCCP. Use of the carpet drag finish is a departure from the tined finish that is normally used by WSDOT. Initial data was collect on pavement wear, ride, and friction resistance to develop a baseline for comparison over time and with other projects that use different finishing techniques such as tining. The project will be monitored for a period of five years to measure the performance of the carpet drag finish with respect to wear, ride, friction resistance, and potentially noise. 17.

Authors:
Anderson,K. W., Uhlmeyer,J., Pierce,L., Weston,J.

Keywords:
accident rates

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This report documents the construction of three special pavement test sections on I-90 east of Spokane, Washington. The test sections included ultra-thin and thin whitetopping, Modified Class D open graded asphalt concrete, and micro/macro surfacing treatment. The majority of the project was built with a ½ inch Superpave mix. The test sections were built to assess their potential as mitigation measures for studded tire wear. Initial data collect on the sections indicate a rate of rutting of 1.8 mm per year on the whitetopping, 2.2 on the Modified Class D, and Superpave sections and a rate of 2.6 mm per year on the micro/macro surfacing section. Extensive cracking was noted in the section of whitetopping with a three inch thickness.

Authors:
Anderson,K. W., Uhlmeyer,J., Pierce,L., Weston,J.

Keywords:
accident rates

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Authors:
Sargeant,S. L., Miller,M. C., May,C. W., Thom,R. M.

Keywords:
accident rates

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Authors:
Kopf,J., Nee,J., Ishimaru,J. M., Hallenbeck,M. E.

Keywords:
accident rates