Citation

Basha P, Ramsey S. ITE J. 1993; 63(5): 30-35.

Copyright

(Copyright © 1993, Institute of Transportation Engineers)

DOI

unavailable

PMID

unavailable

Abstract

A method for analyzing accident rates implemented in Scottsdale, Arizona, is discussed. It is based upon the median rather than the mean, making conformance with a normal data distribution unnecessary. The details are described of the procedure in which accident rates are listed in descending order and the 50th percentile (median) and the 75th and 25th percentiles are determined. A diagram, called the 'Box and Whisker,' is used to depict the information. The calculations are simple and direct, and the technique is primarily graphic. The Box and Whisker technique for understanding and comparing accident rates is an excellent initial analysis tool that enhances the decision process for specific accident analyses. The benefits of the technique are noted.