Citation

Persaud BN, Lord D, Palmisano J. Transp. Res. Rec. 2002; 1784: 57-64.

Affiliation

Ryerson University, Dept Civil Engineering, Toronto, ON M5B 2K3, Canada. Texas A and M University, Texas Transportation Institute, College Station, TX 77843 USA. ITRANS Consulting Inc, Richmond Hill, ON L4B 1J8, Canada.

Copyright

(Copyright © 2002, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

10.3141/1784-08

PMID

unavailable

Abstract

Accident prediction models, also known as safety performance functions, have several important uses in modern-day safety analysis. Unfortunately, calibration of these models is not straightforward. A research effort was undertaken that demonstrates the complexity of calibrating these models for urban intersections. These complexities relate to the specification of the functional form, the accommodation of the peculiarities of accident data, and the transferability of models to other jurisdictions. Toronto data were used to estimate models for three- and four-legged signalized and unsignalized intersections. Then the performance of these models was compared with that of models for Vancouver and California that were recalibrated for Toronto using a procedure recently proposed for the application in the Interactive Highway Safety Design Model (IHSDM). The results of this transferability test are mixed, suggesting that a single calibration factor as is currently specified in the IHSDM procedure may be inappropriate and that a disaggregation by traffic volume might be preferable.