Identifying Access Management Factors Associated With Safety of Urban Arterials Mid-Blocks: A Panel Data Simultaneous Equation Models Approach

Abstract

Objective: The objective of this study was to evaluate the safety impact of selected access management techniques in urban areas because access management techniques play an important role in urban roadway safety on the roadway network.

Methods: In order to correct the interdependency between safety and mobility for heterogeneous mid-block segments, simultaneous equation models were adopted. The panel data structure of the model was used to address the heterogeneity issue for mid-block segments along a corridor. The integrated random coefficient simultaneous equation models were proposed to interpret both issues.

Results: The models developed were used to identify influential factors. The length of mid-block segments, driveway density, and median opening density were among the significant factors found to be associated with crash rate on mid-block segments.

Conclusions: From the results it can be concluded that the access management techniques, mid-block segment length, driveway density, and median opening density are significant factors that influence safety on mid-block segments. The longer the distance between signals, driveways, and median openings, the fewer the potential crashes are. In addition to these access management techniques, land use, especially the commercial land type, influences the safety on mid-block segments.

Keywords:

• access management
• simultaneous equations models
• endogeneity
• heterogeneity
• panel data

Acknowledgments

This study was initially funded by the University Transportation Center at the University of Nevada Las Vegas and subsequently supported by the Fundamental Research Fund for the Central Universities (HUST: 2011QN183), National Natural Science Foundation of China (Nos. 71171087 and 5120822), and Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry of China. Thanks for the data collection from the Nevada Department of Transportation and University of Nevada, Las Vegas.