Speed and Delay on Signalized Arterials

Abstract

This paper presents a model to predict the influence of traffic flow on the running speed of signalized arterials in Montgomery County, Maryland, while controlling for link length, the number of lanes, and route type. The model separates the changes to link running speed due to same-direction traffic and intersection approach delay from cross-traffic. It is found that flow has a small impact on link speed, each 1,000 v/l/h reduces speed by 4–8 k/h. Longer links have higher speeds, indicating that they more closely approximate free-flow conditions. Measures of intersection and link travel times are also compared. Although link running times exceed intersection stopped delay in general, total intersection delay (stopped and approach) exceeds the delay caused by same-direction traffic. This information can inform investment decision makers about roadway and intersection improvements.