APPLICATIONS OF 1985 HIGHWAY CAPACITY MANUAL FOR ESTIMATING DELAYS AT SIGNALIZED INTERSECTIONS
The 1985 Highway Capacity Manual (HCM) contains a procedure for estimating stopped delays at signalized intersections. These estimates are to be used to assess the levels of service at an intersection. The assessed levels of service, in turn, provide a basis for making decisions concerning geometric designs and signal operations. To facilitate sound decision making, the HCM procedure must be able to produce accurate delay estimates. This paper evaluates the reliability of the HCM procedure, based on field data, and discusses needed modifications. The evaluation reveals that the procedure tends to overestimate stopped delays at reasonably well-timed signal operations. The discrepancies between the HCM estimates and the observed delays can be very large even when correct cycle lengths and green durations are used as inputs. Such large discrepancies are attributable in part to the progression adjustments recommended in the HCM procedure. Given actual cycle lengths and green durations, the procedure's ability to correctly identify the levels of service is good. However, a reliable method is needed for estimating average cycle lengths and green durations for traffic-actuated signal operations.
- Record URL:
- Record URL:
-
Availability:
- Find a library where document is available. Order URL: http://worldcat.org/isbn/0309049520
-
Supplemental Notes:
- This paper appears in Transportation Research Record No. 1225, Highway Capacity, Flow Measurement, and Theory. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
-
Authors:
- Lin, Feng-Bor
- Publication Date: 1989
Media Info
- Features: Figures; References; Tables;
- Pagination: p. 18-23
- Monograph Title: Highway capacity, flow measurement, and theory
-
Serial:
- Transportation Research Record
- Issue Number: 1225
- Publisher: Transportation Research Board
- ISSN: 0361-1981
Subject/Index Terms
- TRT Terms: Accuracy; Adjustment factors; Decision making; Estimating; Green interval (Traffic signal cycle); Level of service; Progression (Mathematics); Reliability; Signalized intersections; Stopped time delays; Time duration; Traffic delays; Traffic signal cycle
- Identifier Terms: Highway Capacity Manual
- Uncontrolled Terms: Duration; Modifications
- Old TRIS Terms: Progression
- Subject Areas: Highways; Operations and Traffic Management; I71: Traffic Theory;
Filing Info
- Accession Number: 00494962
- Record Type: Publication
- ISBN: 0309049520
- Files: TRIS, TRB, ATRI
- Created Date: Jun 30 1990 12:00AM