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Title:

Impacts of Separation Distances Between Driveway Exits and Downstream U-turn Locations on Safety Performance of Right Turns Followed by U-turns

Accession Number:

01099176

Record Type:

Component

Availability:

Transportation Research Board Business Office

500 Fifth Street, NW
Washington, DC 20001 United States

Abstract:

The primary objective of this study is to evaluate how the separation distances between driveway exits and downstream U-turn locations affect the safety performance of right-turns followed by U-turns. To achieve the research objective, crash data were collected at 140 street segments in the state of Florida. The selected sites were divided into three groups based on the separation distances measured in the field. T-tests and proportionality tests were performed for comparing crash frequency, crash type, and crash severity between different separation distance groups. Negative-Binomial models were developed for examining the factors that contribute to the crashes at selected street segments. The data analysis results show that the separation distances significantly impact the safety of the street segments between driveways and downstream U-turn locations. A 10% increase in separation distance will result in a 3.3% decrease in total crashes and a 4.5% decrease in target crashes. The models also show that providing U-turns at a signalized intersection will result in more crashes at weaving sections. Thus, if U-turns are to be provided at a signalized intersection, a longer separation distance shall be provided. The results of the study provide transportation decision makers with quantified results about the safety effects of the separation distances between driveways and U-turn locations and are particular helpful in selecting the optimal location of a U-turn bay to facilitate drivers make right-turns followed by U-turns.

Monograph Accession #:

01084478

Report/Paper Numbers:

08-0762

Language:

English

Corporate Authors:

Transportation Research Board

500 Fifth Street, NW
Washington, DC 20001 United States

Authors:

Liu, Pan
Lu, Jian
Chen, Hongyun
Sokolow, Gary

Pagination:

19p

Publication Date:

2008

Conference:

Transportation Research Board 87th Annual Meeting

Location: Washington DC, United States
Date: 2008-1-13 to 2008-1-17
Sponsors: Transportation Research Board

Media Type:

DVD

Features:

Figures (4) ; References (21) ; Tables (5)

Geographic Terms:

Florida

Subject Areas:

Administration and Management; Highways; Operations and Traffic Management; Safety and Human Factors; I82: Accidents and Transport Infrastructure

Source Data:

Transportation Research Board Annual Meeting 2008 Paper #08-0762

Files:

TRIS, TRB

Created Date:

Jan 29 2008 3:05PM