Citation

Kim JK, Wang Y, Ulfarsson GF. J. Transp. Eng. 2007; 133(1): 11-19.

Affiliation

Dept. of Civil Engineering, Washington Univ. in St. Louis, St. Louis, MO 63130-4899, United States.

Copyright

(Copyright © 2007, American Society of Civil Engineers)

DOI

unavailable

PMID

unavailable

Abstract

A microscopic model of freeway rear-end crash risk is developed based on a modified negative binomial regression and estimated using Washington State data. Compared with most existing models, this model has two major advantages: (1) It directly considers a driver's response time distribution; and (2) it applies a new dual-impact structure accounting for the probability of both a vehicle becoming an obstacle (Po) and the following vehicle's reaction failure (Pf). The results show for example that truck percentage-mile-per-lane has a dual impact, it increases Po and decreases Pf, yielding a net decrease in rear-end crash probabilities. Urban area, curvature, off-ramp and merge, shoulder width, and merge section are factors found to increase rear-end crash probabilities. Daily vehicle miles traveled (VMT) per lane has a dual impact; it decreases Po and increases Pf, yielding a net increase, indicating for example that focusing VMT related safety improvement efforts on reducing drivers' failure to avoid crashes, such as crash-avoidance systems, is of key importance. Understanding such dual impacts is important for selecting and evaluating safety improvement plans for freeways.