Citation

Davis G. Transp. Traffic Theory 2002; 15: 247-265.

Copyright

(Copyright © 2002, Publisher varies)

DOI

unavailable

PMID

unavailable

Abstract

This paper adopts the view that the basic level for causal modeling in road safety is that of the individual accident where human decisions interact with physical, deterministic processes. Presented is a feasible program that identifies a measure of causal effectiveness, called probability of necessity (PN), and how the PN arises at both the basic and aggregated levels of the analysis is shown. The argument will be by example that focuses on accidents involving vehicles and pedestrians. The paper will make a connection between PN and accident reduction factors, and will, by using a structural causal model, show how to use PN to assess the potential safety impact of speed controls on individual residential streets. Also illustrated is how PN generalizes the notion of causal factor used in accident reconstruction.