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

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 while 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 annual average daily traffic (AADT) per lane are statistically significant factors that influence crash rates on the segments; moreover, crash rates are significantly influenced by two-directional median opening density