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Field Evaluation of All-Way Stop Control Intersection Capacity

Project #: 4WA106
Start Date: 11/15/2022
End Date: 09/30/2023
Status: Current

All-way stop control (AWSC) is an important type of traffic control at intersections. Using this type of control, all intersection approaches are controlled by stop signs. The fact that vehicles on all intersection approaches must stop before entering the intersection is behind the safety benefits associated with this type of traffic control. However, this traffic control may have negative impact on the maximum number of vehicles entering the intersection from all approaches, i.e., intersection capacity. Estimating intersection capacity is very important for the selection of the appropriate traffic control given prevalent or predicted traffic conditions at the intersection. For AWSC intersections, not only the total traffic demand using the intersection is important, but also the demand on each given approach as all approaches have the same right-of-way priority. Therefore, knowing approach capacity is very important in assessing the suitability of this particular traffic control at a specific intersection site.

This project involves an empirical investigation into the capacity of All-Way Stop-Controlled (AWSC) intersections using a study site in the city of Bozeman, Montana. The data are captured using video records of intersection operations while applying strict protocols in processing the data the individual vehicle level. This level of detail is expected to reveal many important insights into intersection capacity and the important variables that are thought to affect intersection capacity.


The objective of this project is to investigate the capacity of All-Way Stop Controlled (AWSC) intersections using field data and to examine, to the extent practical, important variables that are known to affect the capacity at this type of intersection.

Benefits: Intersections are an essential component of highway networks and are a primary control for corridor capacity due to their complicated movements. They are also the location of a high percentage of collisions. Collecting field observations of the capacity of All-Way Stop Control (AWSC) intersections, which are common in both rural and urban areas, may help road managers and engineers reduce collisions and protect pedestrians, and will indicate the transportation capacity of the corridor on which it is located.


  • Ahmed Al Kaisy
    Ahmed Al Kaisy