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Publication Number: FHWA-HRT-11-067
Date: June 2012

 

Field Evaluation of A Restricted Crossing U-Turn Intersection

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FOREWORD

The Federal Highway Administration Office of Safety Research and Development is focused on improving highway operations and safety by increasing the knowledge and understanding of the effects of intersection design on operational efficiency and safety. In rural areas, four-lane divided access highways often serve as the arteries for mobility and commerce. Local residents and businesses commonly access these highways via two-way stop-controlled intersections. Left turns and through movements onto or across these highways too often result in serious crashes. The restricted crossing U-turn (RCUT) intersection design is intended to address this safety issue. This report includes the results of driver behavior observations at an RCUT intersection in Maryland and the results of an empirical Bayes before after crash analysis for RCUT intersections on two Maryland corridors. This report should be useful to traffic engineers, planners, and officials who are considering safety improvements at unsignalized intersections on four-lane divided highways.

Monique R. Evans
Director, Office of Safety
Research and Development

Notice

This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document. This report does not constitute a standard, specification, or regulation.

The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report because they are considered essential to the objective of the document.

Quality Assurance Statement

The Federal Highway Administration (FHWA) provides high-quality information to serve the Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.

Technical Report Documentation Page

1. Report No.

FHWA-HRT-11-067

2. Government Accession No. 3 Recipient's Catalog No.
4. Title and Subtitle

Field Evaluation of a Restricted Crossing U-Turn Intersection

5. Report Date

June 2012

6. Performing Organization Code
7. Author(s)

Vaughan W. Inman and Robert P. Haas

8. Performing Organization Report No.

 

9. Performing Organization Name and Address

Science Applications International Corporation
8301 Greensboro Drive
McLean, VA 22102-2296

10. Work Unit No. (TRAIS)

11. Contract or Grant No.

DTFH61-08-C-00006

12. Sponsoring Agency Name and Address

Office of Safety Research and Development
Federal Highway Administration
6300 Georgetown Pike
McLean, VA 22101-2296

13. Type of Report and Period Covered

Final Report, May 2008–September 2011

14. Sponsoring Agency Code

HRDS

15. Supplementary Notes

The Contracting Officer’s Technical Representative (COTR) was Chris Monk (HRDS-30). Joe Bared (HRDO-20) also sponsored this research.

16. Abstract

Four-lane divided highways are an economical design solution to increase the capacity of rural highways compared to grade-separated limited access facilities. Compared to two-lane undivided rural highways, four-lane divided highways have markedly lower rates of sideswipe, rear-end, and head-on collisions. However, right-angle crash rates are markedly higher on four-lane divided highway intersections than at two-lane undivided highway intersections, largely as a result of left-turn and through movements from minor roads conflicting with far-side vehicles on the divided highway. The restricted crossing U-turn (RCUT) intersection is a promising treatment to mitigate right-angle crashes where two-lane minor roads intersect with rural four-lane divided highways.

This report includes a comparison of operations at an RCUT intersection in Maryland with a roughly comparable conventional stop-controlled intersection on the same corridor. It also includes before-after crash analyses for intersections converted from conventional to RCUT designs on two Maryland highway corridors. The operational analysis found that conflicts between vehicles entering or crossing the highway from a minor road were reduced, weaving movements were about the same for the two intersection types, the RCUT design added about 1 min to travel time for vehicles making left-turn or through movements from the minor road.

Three approaches were used to estimate the affect of an RCUT conversion on crashes. All three approaches led to the same conclusion: the RCUT design reduces crashes. A simple 3-year before and 3-year after analysis suggested a 30 percent decrease in the average number of crashes per year. An analysis that adjusted the observed crash rate at RCUT locations for the observed crash rate at nearby conventional intersections on the same corridors suggested a 28 percent decrease in the average annual number of crashes. An empirical Bayes analysis that adjusts for, among other things, the expected number of crashes at similar intersections and average annual traffic suggested a 44 percent decrease in crashes. Furthermore, the analyses suggest an overall reduction in crash severity with the RCUT design.

17. Key Words

Superstreet, Safety, Driver behavior, J-turn, Divided highway intersection, Travel time, Crash analysis, Restricted crossing U-turn

18. Distribution Statement

No restrictions. This document is available through the
National Technical Information Service, Springfield, VA
22161.

19. Security Classification
(of this report)

Unclassified

20. Security Classification
(of this page)

Unclassified

21. No. of Pages

49

22. Price

Free

Form DOT F 1700.7 Reproduction of completed page authorized

SI* (Modern Metric) Conversion Factors

Table of Contents

List of Figures

List of Tables

 

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