Citation

Almonte A, Abdel-Aty MA. ITE J. 2010; 80(6): 18-24.

Copyright

(Copyright © 2010, Institute of Transportation Engineers)

DOI

unavailable

PMID

unavailable

Abstract

Although the level of service (LOS) rating is defined based on traffic operating conditions for the road user, the term “safety” has been excluded from the LOS definition since 1994, because of the belief that safety cannot be explicitly defined or quantified. This paper describes a study that was conducted to gain insight into the LOS and traffic safety relationship and how traffic congestion can contribute to crash occurrence at signalized intersections. The study critically reviewed previous studies, extended the methodology adopted in these studies and incorporated LOS as a predominant indicator in several traffic safety models for signalized intersections. Results showed that the LOS could be used as an explicit indicator and predictor in crash frequency models for signalized intersections. LOS appears to be more significant when interacting with other factors and/or characteristics of the transportation facility being studied. The LOS indicator appeared to be more significant than the delay parameters when both were both introduced in the crash frequency models.