PREDICTING PEAK-SPREADING UNDER CONGESTED CONDITIONS
As the resources for expanding street and highway capacity in urban areas have become increasingly scarce, interest has risen in accurately predicting the peak-hour capacity requirements for future years. Much of the travel demand forecasting performed around the country for highway planning has been performed on a twenty-four-hour basis, and peak-hour capacity needs have been estimated by applying a regional factor for the specific facility type or by using the current ratio of peak-hour to twenty-four-hour volume for a specific highway segment under consideration. This method is most often static and does not reflect the reduction in peaking that generally occurs as facilities become congested during the peak hour and trip makers adjust their travel time to avoid the peak. This paper reports the results of research on the peak-spreading phenomenon using traffic data from highway corridors in Arizona, Texas, and California. The data from each corridor covered a period of five to twenty years during which the congestion level in the peak period changed significantly. The research demonstrated that a clear and consistent pattern of peak-spreading emerged for highway facilities as congestion occurred during the three-hour morning and evening peak periods. The relationships derived from the research on peak-spreading have allowed the authors to develop a submodel for the UTPS UROAD assigned package. The new submodel will predict, for each link in the highway network, a peak-hour volume. That peak-hour volume reflects the level of congestion that would result from the predicted three-hour, peak-period volume for the forecast year and the level of capacity planned for each link; and it reflects the effect of peak-spreading that results from the predicted congestion on the facility. More accurate prediction of the peak-hour volumes is also expected to result in better prediction of peak-hour speeds for forecast years. This in turn should result in more accurate forecasting of travel time savings and air quality improvements from highway improvement projects.
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/isbn/0309047692
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Supplemental Notes:
- This paper appears in Transportation Research Record No. 1203, Demand Forecasting and Trip Generation-Route Choice Dynamics. 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
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Authors:
- Loudon, William R
- Ruiter, Earl R
- Schlappi, Mark L
- Publication Date: 1988
Media Info
- Features: Figures; References; Tables;
- Pagination: p. 1-9
- Monograph Title: Demand forecasting and trip generation - route choice dynamics
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Serial:
- Transportation Research Record
- Issue Number: 1203
- Publisher: Transportation Research Board
- ISSN: 0361-1981
Subject/Index Terms
- TRT Terms: Accuracy; Computer programs; Forecasting; Highway corridors; Peak periods; Traffic congestion; Traffic speed; Traffic volume; Travel demand; Urban areas
- Old TRIS Terms: Peak hour traffic spreading
- Subject Areas: Highways; Planning and Forecasting; Public Transportation; I72: Traffic and Transport Planning;
Filing Info
- Accession Number: 00489552
- Record Type: Publication
- ISBN: 0309047692
- Files: TRIS, TRB, ATRI
- Created Date: Nov 30 1989 12:00AM