Modeling the Effects of Rainfall Intensity on Traffic Speed, Flow, and Density Relationships for Urban Roads
Publication: Journal of Transportation Engineering
Volume 139, Issue 7
Abstract
The relationships between traffic speed, flow, and density under various rainfall conditions on urban roads in Hong Kong are investigated in this study. The effects of rainfall intensities are examined empirically, particularly their effects on the reduction of key traffic stream parameters such as free-flow speed, speed at capacity, and capacity (or maximum flow) on urban roads. Rainfall intensity has been found to have significant impacts on urban road key traffic stream parameters, but not on traffic jam density. Generalized speed-flow and speed-density functions are also proposed and calibrated, taking into account the effects of varied rainfall intensity. The calibrated generalized functions are validated with an independent data set from the same location. The generalized speed-flow and speed-density functions are useful for assessing the performance of urban roads, particularly in cites with relatively high annual rainfall intensity. It is believed that the findings could provide better insights into the effects of rainfall intensity on urban road traffic environments for modeling their impacts on road users’ route choice behaviors.
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Acknowledgments
The work described in this paper was jointly supported by two competitive earmarked research grants from the Research Grants Council of the Hong Kong Special Administrative Region (PolyU 5196/10E and 5187/12E), and an internal research grant J-BB7Q from the Research Committee of the Hong Kong Polytechnic University. The authors would like to thank the Transport Department of the Hong Kong Government for providing the JTIS traffic data from 2009 to 2011. The two anonymous reviewers are also acknowledged for their valuable comments that improved the quality of the paper.
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Information & Authors
Information
Published In
Journal of Transportation Engineering
Volume 139 • Issue 7 • July 2013
Pages: 758 - 770
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Jul 3, 2012
Accepted: Feb 1, 2013
Published online: Jun 14, 2013
Published in print: Jul 1, 2013
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