Analysis on Influencing Factors Identification of Crash Rates Using Tobit Model with Endogenous Variable

Xuecai Xu
Huazhong University of Science and Technology

Ahmad Kouhpanejade
University of Nevada, Las Vegas

Željko Šarić
University of Zagreb, Croatia

Abstract

The objective of this study is to identify the influencing factors of crash rates from the perspective of access management techniques in urban areas. The target areas are located in the Las Vegas Metropolitan area, and 19 arterials are selected. In order to address the interdependency between crash rates and travel speeds, and left-censored issue, a tobit model with endogenous variable is presented. The structure of the tobit model addresses the left-censored issue for the segments meanwhile the endogeneity issue between crash rates and travel speeds is explained. The results indicate that there is a strong interdependency between crash rates and travel speeds. The segment length, driveway density, median opening density, posted speed limit and AADT per lane are statistically significant factors that influence crash rates on segments, moreover, crash rates are significantly influenced by two-directional median opening density.