Weekday Vehicle Volume Tables

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How and Where Weekday Vehicle Volumes Were Measured

Vehicle volumes were estimated in two ways for selected freeway locations in the study area:

Average Annual Weekday Vehicle Volume. The average weekday volume is a general measure of the level of usage of the freeway system at a specific location. This value equals the estimated total number of vehicles passing a given location during an average 24-hour weekday period (Monday through Friday), based on data collected during an entire year. The values are based on available vehicle count data collected electronically by WSDOT.

Average Weekday Peak Volume. The average peak volumes represent levels of system usage during the traditionally busiest periods of the day. Average peak vehicle volumes are estimated for four weekday time periods. These periods are

      • the morning peak period (defined as 6:00 AM to 9:00 AM)
      • the evening peak period (defined as 3:00 PM to 7:00 PM)
      • the AM peak hour (the one-hour AM interval with the highest vehicle volume)
      • the PM peak hour (the one-hour PM interval with the highest vehicle volume)

The peak periods represent the traditional morning and evening “rush hour” commute periods, whereas the peak hours represent the highest one-hour traffic volumes during the day. The peak-period measurements are always based on the fixed time periods noted above; the average peak-hour volumes can be based on a different one-hour period from day to day, but always represent the AM and PM hour with the highest volumes. A peak hour normally, though not necessarily, occurs within a peak period; because severe congestion limits the number of vehicles that can use a freeway lane, peak volumes on congested roads can occur outside the fixed peak period.

As with the weekday vehicle volumes, peak vehicle volumes are based on available vehicle count data collected electronically by WSDOT.

Summary system usage statistics have been reported at roughly 23 freeway locations throughout the central Puget Sound freeway network: seven locations on I-5, seven locations on I-405, two on I-90, three on SR 167, and four on SR 520. (The total number of locations may change slightly from year to year, as construction activity and other data collection disruptions may eliminate some data collection locations.)

Average Volumes:

Disclaimer. The contents of this Web page reflect the views of the authors/researchers, who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Washington State Transportation Commission, Department of Transportation, or the Federal Highway Administration. The information presented does not constitute a standard, specification, or regulation.

Revised 22-Mar-2010