Skip to contentUnited States Department of Transportation - Federal Highway Administration FHWA Home
Research Home
Report
This report is an archived publication and may contain dated technical, contact, and link information
Publication Number: FHWA-HRT-09-060
Date: April 2009

Alternative Intersections/Interchanges: Informational Report (AIIR)

PDF Version (13 MB)

PDF files can be viewed with the Acrobat® Reader®

FOREWORD

Today’s transportation professionals, with the limited resources available to them, are challenged to meet the mobility needs of an increasing population. At many highway junctions, congestion continues to worsen, and drivers, pedestrians, and bicyclists experience increasing delays and heightened exposure to risk. Today’s traffic volumes and travel demands often lead to safety problems that are too complex for conventional intersection designs to properly handle. Consequently, more engineers are considering various innovative treatments as they seek solutions to these complex problems.

This report covers four intersection and two interchange designs that offer substantial advantages over conventional at-grade intersections and grade-separated diamond interchanges. It also provides information on each alternative treatment covering salient geometric design features, operational and safety issues, access management, costs, construction sequencing, environmental benefits, and applicability. The six alternative treatments covered in this report are displaced left-turn (DLT) intersections, restricted crossing U-turn (RCUT) intersections, median U-turn (MUT) intersections, quadrant roadway (QR) intersections, double crossover diamond (DCD) interchanges, and DLT interchanges.

Raymond Krammes
Acting 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.

The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report only 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 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-09-060

2. Government Accession No. 3. Recipient’s Catalog No.

4. Title and Subtitle

Alternative Intersections/Interchanges: Informational Report (AIIR)

5. Report Date

April 2010

6. Performing Organization Code

7. Author(s)

Warren Hughes, Ram Jagannathan, Dibu Sengupta, and Joe Hummer

8. Performing Organization Report No.

Project 37769.19

9. Performing Organization Name and Address

Vanasse Hangen Brustlin, Inc. (VHB) 8300 Boone Blvd., Suite 700 Vienna, VA 22182-2626 Subconsultants: North Carolina State University; Persaud Lyon, Inc.; University of Missouri-Rolla

10. Work Unit No. (TRAIS)
11. Contract or Grant No. DTFH61-05-D-00024 (VHB) Task T-06-016

12. Sponsoring Agency Name and Address

U.S. Department of Transportation Federal Highway Administration Office of Safety 1200 New Jersey Ave., SE Washington, DC 20590

13. Type of Report and Period Technical Report Informational Report August 2006 to July 2009

14. Sponsoring Agency Code

FHWA

15. Supplementary Notes

The Federal Highway Administration (FHWA) Office of Safety Research and Development managed this study. The FHWA Office of Safety Research and Development Contract Task Order Manager was Dr. Joe Bared.

Project focus group members contributed significantly to document organization, content, and exhibits. They included Tom Hicks and Saed Rahwanji from the Maryland State Highway Administration; Debbie Self from the Charlotte Department of Transportation; Ed Rice and Jon Obenberger from the U.S. Department of Transportation; Louis Thibault from the U.S. States Access Board; Robert Copp and Jerry Champa from the California Department of Transportation; and Mike Cynecki from the City of Phoenix. In addition, many FHWA staff members participated as focus group members and/or provided comments throughout the project including Neil Spiller, James Colyar, John Halkias, Wei Zhang, Tamara Redmon, Fred Ranck, Brian Chandler, Mary Stringfellow, William Prosser, and Scott Wainwright. The research team is grateful to James Young and the Ohio Department of Transportation for providing the real-world intersection example used in chapter 10.

16. Abstract

Today’s transportation professionals are challenged to meet the mobility needs of an increasing population with limited resources. At many highway junctions, congestion continues to worsen. Drivers, pedestrians, and bicyclists experience longer delays and greater exposure to risk. Today’s traffic and safety problems are more complex and complicated. Conventional intersection/ interchange designs are sometimes found to be insufficient to mitigate transportation problems. Consequently, many engineers are investigating and implementing innovative treatments in an attempt to think outside the box. This report covers four intersection designs and two interchange designs that may offer additional benefits compared to conventional at-grade intersections and grade-separated diamond interchanges. The six alternative treatments covered in this report are displaced left-turn (DLT) intersections, restricted crossing U-turn (RCUT) intersections, median U-turn (MUT) intersections, quadrant roadway (QR) intersections, double crossover diamond (DCD) interchanges, and DLT interchanges. The information presented in this report provides knowledge of each of the six alternative treatments including salient geometric design features, operational and safety issues, access management issues, costs, and construction sequencing and applicability.

17. Key Words

Alternative intersections, Alternative interchanges, CFI, XDL, DDI, DLT, DCD, MUT, Median U-turn, Diverging diamond, Displaced left-turn, Super street, Continuous flow intersection, J-turn

18. Distribution Statement

No restrictions.

19. Security Classif. (of this report)

Unclassified

20. Security Classif. (of this page) Unclassified

21. No. of Pages

340

22. Price

Form DOT F 1700.7 (8-72) Reproduction of completed pages authorized

SI* (Modern Metric) Conversion Factors

TABLE OF CONTENTS

CHAPTER 1. INTRODUCTION

CHAPTER 2. DISPLACED LEFT-TURN INTERSECTION

CHAPTER 3. MEDIAN U-TURN INTERSECTION

CHAPTER 4. RESTRICTED CROSSING U-TURN INTERSECTION

CHAPTER 5. QUADRANT ROADWAY INTERSECTION

CHAPTER 6. OTHER INTERSECTION CONFIGURATIONS

CHAPTER 7. DOUBLE CROSSOVER DIAMOND INTERCHANGE

CHAPTER 8. DISPLACED LEFT-TURN INTERCHANGE

CHAPTER 9. OTHER INTERCHANGE CONFIGURATIONS

CHAPTER 10. ALTERNATIVE INTERSECTION ASSESSMENT METHODOLOGY

ACKNOWLEDGEMENTS

REFERENCES

LIST OF FIGURES

LIST OF TABLES

 

ResearchFHWA
FHWA
United States Department of Transportation - Federal Highway Administration