Using extreme value theory to evaluate the leading pedestrian interval road safety intervention

Hewett, Nicola; Fawcett, Lee; Golightly, Andrew; Thorpe, Neil

Abstract

Improving road safety is hugely important with the number of deaths on the world's roads remaining unacceptably high; an estimated 1.3 million people die each year as a result of road traffic collisions. Current practice for treating collision hotspots is almost always reactive: once a threshold level of collisions has been overtopped during some pre‐determined observation period, treatment is applied (e.g., road safety cameras). Traffic collisions are rare, so prolonged observation periods are necessary. However, traffic conflicts are more frequent and are a margin of the social cost; hence, traffic conflict before/after studies can be conducted over shorter time periods. We investigate the effect of implementing the leading pedestrian interval treatment at signalised intersections as a safety intervention in a city in north America. Pedestrian‐vehicle traffic conflict data were collected from treatment and control sites during the before and after periods. We implement a before/after study on post‐encroachment times (PETs) where small PET values denote ‘near‐misses’. Hence, extreme value theory is employed to model extremes of our PET processes, with adjustments to the usual modelling framework to account for temporal dependence and treatment effects.

Citation

Hewett, N., Fawcett, L., Golightly, A., & Thorpe, N. (2024). Using extreme value theory to evaluate the leading pedestrian interval road safety intervention. Stat, 13(2), Article e676. https://doi.org/10.1002/sta4.676

• Journal Article Type: Article
• Acceptance Date: Mar 18, 2024
• Online Publication Date: Apr 18, 2024
• Publication Date: Jun 1, 2024
• Deposit Date: Apr 25, 2024
• Publicly Available Date: Apr 25, 2024
• Journal: Stat
• Electronic ISSN: 2049-1573
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 13
• Issue: 2
• Article Number: e676
• DOI: https://doi.org/10.1002/sta4.676
• Keywords: traffic conflicts, leading pedestrian interval (LPI), extreme value theory (EVT), before‐after analysis, bivariate threshold excess model, post‐encroachment time (PET)
• Public URL: https://durham-repository.worktribe.com/output/2389911