All-way stop control (AWSC) is a superb intersection treatment, producing large crash savings and even mobility at a low cost. In North Carolina, previous research efforts sponsored by the NC Department of Transportation (NCDOT) revealed that AWSC works well under circumstances that previously thought to be questionable including but not limited to large truck percentages, unbalanced demands, and on high-speed roads. Hence, AWSC has been considered by NCDOT as the leading safety treatments. To date, there are more than a hundred AWSC intersections across the state, with more to be installed in the near future.
However, the precondition for AWSC to keep users safe is that drivers are compliant with stop signs, which is not always possible, particularly if drivers see no reason for a stop sign or if drivers are frustrated by the overuse of stop signs. In summary, the effectiveness of an AWSC will be achieved when used at the right place and under the right conditions, while overuse of AWSCs may reduce their effectiveness. While in current practice, there lacks a clear and scientific understanding of the effects of high concentrated AWSCs on the mobility of corridors and drivers' compliance to stop signs. In this regard, there is an urgent need to investigate if there are factors or thresholds that provide reduced safety benefits when AWSC installations are installed in succession along a corridor. If increases in risk are proven to be related to one or more factors, it is necessary to understand when those safety risks are most likely to be present and why.
The proposed research aims to collect measurable data on the mobility and safety performance of corridors with successive AWSCs and investigate driver behavior when driving through concentrated AWSCs. Specifically, the objective of this research is to 1) investigate safety performance of concentrated AWSCs in terms of crash rate and driver compliance to successional AWSC intersections; based on which, figure out factors that affect drivers compliance to AWSC and assess the potential crash risk caused by violation of stop signs; 2) assess the mobility impacts of AWSC intersection along corridors in terms of travel time and delay, compared to other intersection designs such as two-way stop-control and signal control, etc. The outcome of this research will be practice-ready guidance on the applicability of AWSC intersection along corridors such as the maximum or optimal number of AWSC intersections per unit distance to be deployed along a corridor, which will provide NCDOT planners and engineers with a clear understanding of the density limit on AWSC during the preliminary planning stage of capital improvement projects.
