Award Date

5-2010

Degree Type

Dissertation

Degree Name

Doctor of Philosophy in Engineering

Department

Civil and Environmental Engineering

First Committee Member

Hualiang (Harry) Teng, Chair

Second Committee Member

Mohamed S. Kaseko

Third Committee Member

Moses Karakouzian

Fourth Committee Member

Alexander Paz

Graduate Faculty Representative

Hokwon A. Cho

Number of Pages

131

Abstract

The access provided by streets and highways to adjacent lands are managed by controlling the spacings between the access points including signals, driveways, and media openings on mid-block segments, and setting the limit on the corner clearances around intersections. There have been studies on evaluating the impact of access management techniques on safety and mobility in urban areas. Samples of mid-block segments and intersections can be collected from selected arterials. Because the mid-block segments or intersections in the same arterials share the same missing information, safety and mobility on them show unique features that should be taken into account when modeling. In this study panel data models were proposed for safety analysis on mid-block segments and intersections. A virtual "mid-block" segment was assumed to exist for each arterial. The observations of the mid-block segments on this arterial were viewed as repeated observations for the virtual "mid-block" segment. This perspective of the mid-block segments or intersections over space made it feasible for the panel data model to evaluate the impact of access management techniques on safety. In addition, this study also recognized that interdependency existed between safety and mobility for a mid-block segment or an intersection. Therefore, for mid-block segments, simultaneous equation models were adopted by integrating with the panel data modeling structure. For intersections, the interdependence between safety and mobility wasn't considered due to the lack of data, and only count data models combining with the panel data structure was developed. Data were collected from different sources for the urban areas of Southern Nevada. The results from the models for mid-block segments indicate that there is a strong interdependency between safety and mobility. The length of mid-block segments, driveway density, and median opening density are very significant factors that influence crash rate on mid-block segments. From the results of the models for intersections, it was found that corner clearance significantly influenced the number of crashes occurred at intersections. Other factors also influence the occurrence of crashes at intersections that include land use, traffic flow, number of lanes, and posted speed limit.

Keywords

Access management techniques; City blocks; Random coefficient simultaneous equations model; Random-effects negative binomial regression model; Safety and mobility; Streets – Design and construction; Traffic engineering; Traffic flow

Disciplines

Civil and Environmental Engineering | Infrastructure | Transportation | Urban, Community and Regional Planning | Urban Studies

Language

English