Data-Driven Statewide Prioritization of Corridors for Signal Retiming Projects

Abstract

While the introduction of emerging technologies has substantially improved the way traffic signals are operated, most agencies still rely on the traditional approach of retiming, which is typically initiated by “trigger” events (e.g., signal retiming occurs due to citizen calls, a major change in land use or roadway geometry, sustained oversaturation, safety concerns). The approach of using triggers can work effectively for small agencies, however, such an approach may not be sustainable for agencies that operate a high number of corridors. Additionally, agencies are often limited in terms of their budget to retime signals. Therefore, strategic selection of corridors is important to effectively utilize existing resources. Recently data-driven methods for prioritization of corridors for retiming were proposed. However, these methods either rely on datasets that are not widely available or only account for corridor performance (e.g., speed) without considering other relevant factors that can be important during prioritization. Further, most prior attempts estimated corridor performance based on the simple average performance of individual intersections. Such an approach may distort the results for corridors with largely dispersed intersection performance. To overcome these challenges, this study proposes a novel ranking approach based on data that is available to most agencies and incorporates normalized corridor delay, corridor travel time reliability, annual average daily traffic, and time since last retiming. The proposed method was applied to 120 corridors (consisting of 756 signals) across the State of Ohio in the US. It was found that ranking results are highly aligned with agency representatives’ expectations, as most of the highly ranked corridors have already been identified by agency representatives for future retiming projects. Moreover, the before-and-after analysis from recent retiming studies on highly ranked corridors revealed substantial benefits, confirming the effectiveness of the proposed ranking method. The proposed ranking and prioritization method discussed in this paper could be beneficial for agencies with large number of corridors and limited budget and resources so they can effectively prioritize their corridors for future signal retiming projects.