U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
| REPORT |
| This fact sheet is an archived publication and may contain dated technical, contact, and link information |
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| Publication Number: FHWA-HRT-20-008 Date: May 2020 |
Publication Number: FHWA-HRT-20-008 Date: May 2020 |
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Merging, diverging, and weaving areas are major bottleneck locations on uninterrupted flow facilities and are a significant source of recurring congestion. This report summarizes the development of five alternative designs for application at freeway merging, diverging, and weaving areas: split merge points, managed lanes on the right-hand side, mainline metering, coordinated ramp metering, and speed optimization via traffic calming devices. This report also includes simulations of the innovative treatments to evaluate the benefits of the designs. This report will be of interest to State and local departments of transportation who are interested in exploring innovative methods to more effectively manage their facilities.
Brian P. Cronin, P.E.
Director, Office of Safety and Operations
Research and Development
Notice
This document is disseminated under the sponsorship of the U.S. Department of Transportation (USDOT) 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.
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Technical Report Documentation Page
| 1. Report No.
FHWA-HRT-20-008 |
2. Government Accession No. | 3 Recipient's Catalog No. | ||
|---|---|---|---|---|
| 4. Title and Subtitle
Alternative Designs to Alleviate Freeway Bottlenecks at Merging, Diverging, and Weaving Areas |
5. Report Date
May 2020 |
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| 6. Performing Organization Code | ||||
| 7. Author(s)
David K. Hale (ORCID: 0000-0001-5486-9367), Jiaqi Ma (ORCID: 0000-0002-8184-5157), Amir Ghiasi (ORCID: 0000-0002-0986-9840), Pascal Volet (ORCID: 0000-0002-1753-0935), Burak Cesme (ORCID: 0000-0002-1265-981X), Alexandra Kondyli (ORCID: 0000-0002-3462-0000), Bastian Schroeder (ORCID: 0000-0001-8916-421X), Sonika Sethi (ORCID: 0000-0002-5236-0003), Laura Torres (ORCID: 0000-0001-8250-0436), and Francois Belisle (ORCID: 0000-0003-1592-3986) |
8. Performing Organization Report No. | |||
| 9. Performing Organization Name and Address
Leidos, Inc. |
10. Work Unit No. | |||
| 11. Contract or Grant No.
DFTH6116D00030 |
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| 12. Sponsoring Agency Name and Address
U.S. Department of Transportation |
13. Type of Report and Period Covered
Final Report; July 2017–September 2018 |
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| 14. Sponsoring Agency Code
HRDO-20 |
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| 15. Supplementary Notes
The Contracting Officer's Representative was Joe Bared (HRDO-20). |
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| 16. Abstract
Alternative intersections and interchanges brought major benefits to the United States during the 2008–2018 time period. Given the positive impacts, it stands to reason that similar breakthroughs might be possible at freeway merge and diverge locations. This report describes the outcomes of a project that examined this possibility. The primary tool of evaluation was sensitivity analysis via microscopic traffic simulation, also known as microsimulation. The split merge design, and the positioning of managed lanes on the right side of the freeway, are two unrelated designs that showed excellent promise (in terms of benefit—cost ratio). Coordinated ramp metering did not show significant additional benefits beyond conventional asservissement lin’eaire d'entr’ee autorouti‘ere, also known as ALINEA, metering. Speed optimization showed excellent benefits but only during narrow ranges of traffic congestion. Mainline metering also showed reasonably good benefits but could be challenging to implement. It is conceivable that speed optimization and mainline metering could produce more favorable benefit—cost ratios if they could be implemented via connected and automated vehicle (CAV) technologies. However, the split merge and right-side managed lane designs produced excellent benefits without the need for CAV technologies. |
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| 17. Key Words
Split merge, managed lanes, mainline metering, coordinated ramp metering, speed optimization, freeway merge |
18. Distribution Statement
No restrictions. This document is available to the public through the National Technical Information Service, Springfield, VA 22161. |
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| 19. Security Classification (of this report) Unclassified |
20. Security Classification (of this page) Unclassified |
21. No. of Pages
182 |
22. Price
N/A |
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| Form DOT F 1700.7 (8-72) | Reproduction of completed page authorized |
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