1. Report No.
FHWA-HOP-09-008 |
2. Government Accession No. |
3. Recipient's Catalog No. |
4. Title and Subtitle
Signal Timing Under Saturated Conditions |
5. Report Date
November 2008 |
6. Performing Organization Code |
7. Author(s)
Principal Investigator: Richard W. Denney, Jr., P.E.
Co-Authors: Larry Head, Ph.D., Kevin Spencer |
8. Performing Organization Report No.
Project |
9. Performing Organization Name and Address
Booz Allen
Sub-consultants: Iteris, Inc.; University of Arizona; Econolite |
10. Work Unit No. (TRAIS) |
11. Contract or Grant No.
Contract No. DTFH61-06-D-00006 |
12. Sponsoring Agency Name and Address
U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590 |
13. Type of Report and Period Covered
Final Report
October 2006 to September 2008 |
14. Sponsoring Agency Code
HOP |
15. Supplementary Notes
Eddie Curtis (Eddie.Curtis@fhwa.dot.gov)
was the Technical Representative for the Federal Highway Administration. Agency
experts and consultants provided interviews in support of identifying the
state of the practice, including:
- Gerard de Camp, independent consultant
- Steven Click, Tennessee Tech University (formerly with North Carolina DOT)
- Woody Hood, Maryland State Highway Administration
- Eric Nelson, Harris County (Texas) Department of Transportation
- Gary Pietrowicz, Road Commission of Oakland County (Michigan)
- Ziad Sabra, Sabra-Wang and Associates
- Bill Shao, Los Angeles Department of Transportation
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16. Abstract
This report provides guidance to practitioners on effective strategies to mitigate the effects of congestion at signalized intersections. The scope is limited to single intersections and does not address network-level strategies. The strategies are defined in terms of their underlying objective. Under congested conditions, traditional objectives and performance measures shift from progression and minimizing delay to maximizing throughput and managing queues. Experts were interviewed to identify the strategies and tactics they used to address congested intersections, a discussion of their methods is presented. Select strategies were studied further, particularly the belief that longer cycles are more efficient, and the effects of buses on signal timing in grid networks. The research revealed that long cycle lengths may not be more efficient at intersections where long queues starve turn lanes. In grid networks, the cycle length that is just long enough to reliably serve busses from a near-side stop was found through simulation to prevent the development of residual queues.
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17. Key Words
Signalized Intersections, Traffic Signal Timing, Congestion, Cycle Lengths, Throughput, Queue Management |
18. Distribution Statement
No Restrictions. This document is available to the public. |
19. Security Classification (of this report)
Unclassified |
20. Security Classification (of this page)
Unclassified |
21. No of Pages
76 |
22. Price
N/A |
