How does the incompatibility of different vehicle types affect the odds of driver injury?

Abstract

The effect of vehicles’ compatibility on the odds of death or injury of drivers involved in two-vehicle crashes was investigated. This was done through indexing Crashworthiness (CW) and Crashaggressivity (CA) of major vehicle types. For this purpose, a dataset consisting the information about 551,138 drivers involved in two-vehicle crashes in Iran was used and a two-step analysis framework was employed. In this regard, the Classification and Regression Tree (CART) method was applied in the first step to identify the most significant factors contributing to drivers’ Injury Status (IS). Next, Generalized Estimating Equations (GEE) with a Binomial distribution and a Logit link function were constructed to examine the CW and CA of different vehicle types while considering potential correlation of injury status of the two drivers involved in the same crash. As a result, the most incompatible combination of vehicles in terms of CW and CA were identified and their effects on the IS of drivers were discussed. Results also revealed that other crash characteristics such as rural crashes, head-on collisions, and crashes which occur at sunrise might significantly increase the odds of driver’s death or injury. The findings of this study can be compared with the results of other similar studies across the world to obtain a holistic view over the impact of vehicle incompatibility on the traffic safety.