Logistic regression was applied to accident-related data collected from traffic police records in order to examine the
contribution of several variables to accident severity. A total of 560 subjects involved in serious accidents were sampled. Accident
severity (the dependent variable) in this study is a dichotomous variable with two categories, fatal and non-fatal. Therefore, each
of the subjects sampled was classified as being in either a fatal or non-fatal accident. Because of the binary nature of this
dependent variable, a logistic regression approach was found suitable. Of nine independent variables obtained from police accident
reports, two were found most significantly associated with accident severity, namely, location and cause of accident. A statistical
interpretation is given of the model-developed estimates in terms of the odds ratio concept. The findings show that logistic
regression as used in this research is a promising tool in providing meaningful interpretations that can be used for future safety
improvements in Riyadh. © 2002 Elsevier Science Ltd. All rights reserved.