Assessing the Safety Effects of Removing Highway Mainline Barrier Toll Plazas

Abstract

Toll plazas create a number of bottlenecks on highways. They can induce motor vehicle crashes and also put workers such as toll collectors at risk. Enhancing safety at toll plazas is crucial to improving safety on tolled roadways. This study aims to evaluate the safety effects of removing mainline barrier toll plazas on highways using empirical Bayesian (EB) methodology. Recent removals of barrier toll plazas on the Garden State Parkway in New Jersey were used as a case study. Multiple-year traffic and crash data before and after the removals of the barrier toll plazas were used for evaluation. Toll plaza crash frequency models as a function of traffic flow and other relevant factors were developed, with the modeling results suggesting that there is a nonlinear relationship between toll plaza crash occurrences and both traffic flow as well as tollbooth configurations. The EB approach is also used to predict crash frequency assuming that the barrier tollbooths were not removed. These EB-based estimates were compared with the observed number of crashes after the removals of the toll plazas. Individual comparisons show reductions in crash occurrence at almost all of the toll plazas and an estimated reduction of 42.1% overall at all toll plazas due to the removal of the barrier tollbooths. The estimated crash cost was reduced by 40.1%. These estimated reductions demonstrate that the removal of barrier toll plazas is a very beneficial countermeasure towards improving safety of toll roads. As the study was performed based on multiple sites along a highway, it would be helpful to learn more lessons from other locations given the availability of reliable data for model development and validation.