Differences in Freeway Capacity by Day of the Week, Time of Day, and Segment Type
Publication: Journal of Transportation Engineering
Volume 135, Issue 7
Abstract
Capacity has traditionally been defined deterministically, and has been assumed to occur immediately before breakdown. Recent studies, however, have shown that the value of capacity, i.e., maximum throughput, is probabilistic, and does not always occur immediately before the breakdown. Four different types of flows (i.e., maximum prebreakdown flow, breakdown flow, maximum queue discharge flow, and average queue discharge flow) referred to as “capacity flows” in this paper, are considered to examine how they differ by day of the week and time of the day, and whether they are significantly different by type of freeway segment. Speed and volume data were obtained, which were initially collected by remote traffic microwave sensors at the US-202 southbound near Philadelphia, from May to August 2004. The four types of flows described above were collected and distinguished by time period, day of the week, and segment type. In conclusion, the mean capacity flows were different during different times of the day, but were the same each day of the week. In comparing segment types, capacity flows per lane are generally not equal between merging, diverging, weaving, and lane drop segments.
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Acknowledgments
This work was sponsored by the National Science Foundation (NSF) under 03–556. The contents of this paper reflect the views of the writers, who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views of NSF.
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Information & Authors
Information
Published In
Journal of Transportation Engineering
Volume 135 • Issue 7 • July 2009
Pages: 416 - 426
Copyright
© 2009 ASCE.
History
Received: Apr 3, 2007
Accepted: Feb 27, 2009
Published online: Jun 15, 2009
Published in print: Jul 2009
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