Analysis of Risk Factors Affecting the Severity of Intersection Crashes by Logistic Regression

Abstract

Objective: The objective of this research was to study the risk factors that significantly influence the severity of intersection crashes for vehicle occupants, as well as for pedestrians and other vulnerable road users.

Methods: Logistic regression was applied as the method in this study to analyze a data set of intersection crashes involving casualties in Victoria, Australia, for the period January 2000 to December 2009.

Results: Seven risk factors obtained were found to be significantly associated with the severity of intersection crashes, including driver age and gender, speed zone, traffic control type, time of day, crash type, and seat belt usage.

Conclusions: This study found that male drivers as well as older drivers (age 65 and above) had higher odds of being involved in fatal intersection crashes. Intersection crashes occurring between midnight and early morning (12:00 a.m. to 5:59 a.m.), in 100 km/h speed zones, or with no traffic control had a higher odds of a fatal outcome than their counterpart categories. Furthermore, intersection crashes involving pedestrians or a non–seat belt–wearing driver were more likely to lead to a fatal outcome. In general, identification of risk factors and the discussion of the odds ratio between levels on the impact of the intersection crash severity would be beneficial for road safety stakeholders to develop initiatives to reduce the severity of intersection crashes.

Keywords:

• Intersection crash severity
• Risk factor
• Logistic regression
• Odds ratio

ACKNOWLEDGMENTS

The authors are grateful to Michael Fitzharris for his time spent on proofreading draft versions and helpful comments. Thanks also to Effie Hoareau for her assistance with data management and Eve Mitsopoulos-Rubens for providing valuable suggestions.