Wood guardrail posts can be inspected for decay by using a non-destructive testing technique called stress wave timing (SWT). This project investigated the integrity of wood guardrail posts in strategic locations of Washington state using SWT and then analyzed the data to determine factors that may lead to increased wood decay rates. The researchers determined that high climate index, , a measure of a region’s average annual rainfall and temperature, and poor preservative retention levels were associated with high decay rates. WSDOT will be able to use the results of this project in considering approaches to managing its guardrail assets in the future.

Because drivers respond differently to different signal phasing sequences, engineers need to evaluate how drivers interpret the message that each phasing sequence is trying to convey. This research evaluated the safety and operational impacts of different left turn movement treatments at signalized intersections by using crash, video, and survey data. The results should help decision makers select more suitable signal phasing plans under various operational conditions.

Pavement markings such as single and double divider lines, edge lines, crosswalks, and bike lane markings are critical in guiding roadway users. However, pavement markings can also lead to catastrophic crashes for motorcyclists and bikers when they are wet or icy. This study evaluated three different pavement marking materials in dry, wet, and icy conditions, in the laboratory and in the field, to help improve rider safety.