Traffic Signal Systems Solutions Toolbox: A Case Study from Pennsylvania

Abstract

The selection of the appropriate traffic signal systems solution (e.g., fully actuated [free] control, pretimed control, adaptive traffic signal control, traffic responsive plan) is critical to ensuring efficient traffic operations. The success of any selected solution is largely dependent on corridor characteristics and the nature of the experienced problems on the corridor. In addition, agency capability and constraints (e.g., staffing) along with infrastructure needs (e.g., detection) are other factors that are sometimes overlooked but can be critical during the selection process. So far, researchers have proposed tools, guidelines, and recommendations typically to select a single solution (e.g., adaptive) primarily by observing only corridor operational characteristics. Such practice leaves traffic engineers without an appropriate process/tool that can evaluate whether some other traffic solutions are more appropriate for given conditions. Therefore, the objective of this study is to develop a comprehensive traffic signal systems solutions toolbox that can incorporate corridor characteristics, operational objectives, agency capabilities, and agency constraints and offer a broad range of signal control strategies as solutions. The developed toolbox relies on data that are readily available to most agencies, such as annual average daily traffic and vehicle probe data, and incorporates a range of factors related to corridor characteristics and agency capabilities and constraints. The toolbox was applied to three corridors in Pennsylvania, U.S. Results from the case studies demonstrated that the toolbox could provide the appropriate recommendations based on unique circumstances. Additionally, the recommended solutions were generally in line with the expectations of agency representatives.