Traffic intersections can be dangerous, particularly for pedestrians. Pedestrian safety is important, and many pedestrian crashes occur at intersections where the walk sign gives the pedestrian the right of way. Vehicle drivers, however, may be distracted or not see the pedestrian. Several studies have been conducted that identify solutions to improve pedestrian safety. One such concept, the leading pedestrian interval, has been identified by the Federal Highway Administration as a proven countermeasure. With an LPI, the traffic signal timing allows pedestrians to enter the crosswalk several seconds before a vehicle receives a green light. While effective, LPIs can result in traffic delays, so jurisdictions have taken into account several factors, including crash history, pedestrian volume, and traffic patterns, when deciding where and whether to deploy LPIs. However, what are the quantitative impacts of different factors on turning vehicle–pedestrian crash frequency as they relate to LPI implementation guidelines?
Researchers Faria Raha, Anthony M. Eschen, Steven R. Gehrke, Edward J. Smaglik, and Brendan J. Russo decided to find out. Following an extensive literature review, the authors used the city of Phoenix as a case study to analyze city-supplied crash data, manually collect geometric elements from signalized intersections, and obtain daily traffic data from the Arizona Department of Transportation. Using this data, they developed a model to analyze factors associated with turning vehicle–pedestrian crash frequency, as well as exploring the percent increase in crash frequency with expanded variabilities (e.g., four crosswalks, increased activity, and/or transit stops). Learn more about this research and how practitioners can use this approach to establish a weighted concept for future LPI implementations. “Where to Implement Leading Pedestrian Intervals: An Examination of Turning Vehicle–Pedestrian Crashes at Signalized Intersections” appears in the Journal of Transportation Engineering, Part A: Systems at https://doi.org/10.1061/JTEPBS.TEENG-8676. The abstract is below.
Abstract
Pedestrian safety is a critical transportation and public health issue, with fatalities increasing substantially over the past decade. Given this trend, it is important to understand where and when to most effectively implement countermeasures that help prevent pedestrian crashes, injuries, and fatalities. The leading pedestrian interval (LPI) is one such countermeasure which is considered relatively low-cost and has been shown to improve pedestrian safety. The LPI gives pedestrians a WALK indication 3–7 s before parallel vehicles receive a green indication at signalized intersections, potentially reducing the probability of turning vehicle–pedestrian crashes. LPI implementation may depend on many factors, and several implementation guidelines exist; however, these guidelines can vary from jurisdiction to jurisdiction, and weighting schemes may not always be based on empirical data. To address this issue, this study utilized roadway, traffic, and built environment data from 1,067 signalized intersections in Phoenix, Arizona, along with 2016–2022 crash data in developing a negative binomial regression model to analyze factors associated with turning vehicle–pedestrian crashes. Model results were compared with existing guidelines, and several variables commonly considered for LPI implementation were found to be significant predictors of turning vehicle–pedestrian crash frequency including activity density, major and minor road volumes, transit stop presence, proximity to schools, and number of intersection legs, among others, all at differing magnitudes. Ultimately, the relative predicted impacts of these characteristics may be useful to practitioners, researchers, and policymakers by providing data-driven evidence to help establish weighting schemes and other considerations for future iterations of LPI implementation guidelines.
Explore the findings and how they might affect your decision to implement an LPI in the ASCE Library: https://doi.org/10.1061/JTEPBS.TEENG-8676.
