Applying Travel-Time Reliability Measures in Identifying and Ranking Recurrent Freeway Bottlenecks at the Network Level

Abstract

The primary purpose of this study is to develop a systematic approach to effectively identifying and ranking recurrent freeway bottlenecks using travel-time reliability (TTR) measures. To achieve this goal, three subtasks are undertaken: (1) to identify recurrent freeway bottlenecks at the network level, (2) to rank discerned freeway bottlenecks, and (3) to examine the impacts of different threshold values used in defining TTR measures. Research results suggest that two TTR measures, namely the frequency of congestion (FOC) and planning time index (PTI), are suited to identify and rank recurrent freeway bottlenecks at the network level. A case study is performed to validate the feasibility of the proposed methodology using vehicle probe data collected on four interstate freeways in Mecklenburg County, North Carolina, in 2015. Suggestions about the selection of threshold values in defining FOC and PTI for freeway bottleneck and congestion analysis are also provided. The findings of this study can provide insightful and useful information for traffic engineers and decision makers in identifying recurrent freeway bottlenecks and in developing effective congestion mitigation strategies for planning applications.