Emergency Routing Signs Pilot on the I-81 Corridor in the Staunton Area

About the report

Traffic incidents on the Interstate 81 corridor account for approximately 77% of all delays, significantly affecting regional mobility and roadway capacity. To enhance incident management and reduce the logistical burdens associated with manual detour deployment, the Virginia Department of Transportation’s (VDOT) Staunton District initiated a pilot project to evaluate the efficacy of permanently-installed emergency routing signs. This study assessed the effect of these signs on detour operations and traffic diversion behavior using a mixed-methods approach that integrates qualitative data from semi-structured interviews with quantitative metrics from traffic incidents, traffic speeds, origin-destination, and traffic volume data from multiple VDOT and third-party sources.

The study employed a comparative before-and-after analysis across four case studies, including three incident-related and one work zone-related detours, to quantify improvements in operational efficiency and shifts in motorist route choice. Information gathered through interviews with Staunton District personnel provided critical context for interpreting quantitative analysis, offering insights into personnel requirements and decision-making workflows.

Findings indicate that permanently-installed emergency routing signs facilitated more rapid detour activation by eliminating the need for manual signage setup, thereby reducing activation latency and allowing VDOT incident responders to focus on scene clearance. Compared with the before period, the time required to activate the detour decreased by approximately 1 hour. These operational efficiencies translate into reduced queuing delay benefits; at the 28% baseline compliance rate, rapid activation generates roughly $16,000 in benefits, based on case study results. The results of this pilot provide a technical foundation for future VDOT policy decisions. The study recommends refining operational procedures and processes to maximize the effectiveness of permanently-installed routing signs, particularly to better guide motorists onto the designated detour route when queue spillback extends beyond the primary decision points of the designated detour route.

_{Disclaimer Statement:The contents of this report reflect the views of the author(s), who is 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 Virginia Department of Transportation, the Commonwealth Transportation Board, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Any inclusion of manufacturer names, trade names, or trademarks is for identification purposes only and is not to be considered an endorsement.}

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