Experimental Features and Characteristics of Speed Dispersion in Urban Freeway Traffic

Characteristics of speed dispersion in urban freeway traffic are presented. Two definitions of speed dispersion are proposed: the standard deviation of the individual speeds and the average speed difference of two neighboring vehicles. On the basis of the definitions, traffic data obtained from two urban freeways in China are studied, and different characteristics of speed dispersion are found in four substates of traffic flow, which correspond to four regions in the empirical fundamental diagram. In the bunching state of congested traffic, the flow rate decreases with an increase in speed dispersion at a given mean speed. In the bunching state of fluid traffic, the speed dispersion of traffic flow is small, and in the free state of fluid traffic, speed dispersion is distributed in a disorderly manner in a wide range. Such phenomena are more remarkable under the definition of the average speed difference for speed dispersion. In addition, some possible explanations are presented for the characteristics of speed dispersion in each traffic substate. These speed dispersion studies provide a new approach for microscopic modeling and understanding of traffic flow characteristics.

• Record URL:
  https://doi.org/10.3141/1999-16
• 
• Summary URL:
  http://scholar.google.com/scholar_lookup?title=Experimental+Features+and+Characteristics+of+Speed+Dispersion+in+Urban+Freeway+Traffic&author=H.+Wang&author=W.+Wang&author=X.+Chen&author=J.+Chen&author=J.+Li&publication_year=2007
• Availability:
  • Find a library where document is available. Order URL: http://www.trb.org/Main/Public/Blurbs/159463.aspx
• Authors:
  • Wang, Hao
  • Wang, Wei
  • Chen, Xuewu
  • Chen, Jun
  • Li, Jie
• Publication Date: 2007

Language

• English

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 150-160
• Monograph Title: Traffic Flow Theory 2007
• Serial:
  • Transportation Research Record: Journal of the Transportation Research Board
  • Issue Number: 1999
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Freeways; Microscopic traffic flow; Standard deviation; Traffic congestion; Traffic flow theory; Traffic models; Traffic speed; Urban areas; Urban highways
• Uncontrolled Terms: Speed dispersion
• Geographic Terms: China
• Subject Areas: Highways; Operations and Traffic Management; I71: Traffic Theory;

Filing Info

• Accession Number: 01049562
• Record Type: Publication
• ISBN: 9780309104258
• Files: TRIS, TRB, ATRI
• Created Date: Feb 8 2007 5:47PM