Dynamics of Urban Network Traffic Flow During a Large-Scale Evacuation

This paper explores some of the dynamics of urban network traffic flow during a large-scale evacuation in the context of the network fundamental diagram (NFD). The structure of the evacuation demand can significantly affect network performance. A radial-shaped structure results in a more stable network recovery compared with a directional evacuation structure. This study confirms the existence of unloading–reloading hysteresis when a network is subject to successive cycles of loading and unloading. If a network undergoes a complete or near-complete recovery, the reloading path in the NFD follows almost the same path as in the initial loading. Results suggest that the linear relationship between average network flow and trip completion rate does not always hold, as previously thought. The relationship becomes highly scattered and nonlinear when the network is highly congested and under disruption and the number of adaptive drivers is sufficiently large. Frequent route switching by adaptive drivers can artificially increase the average network flow but does not necessarily increase the network output (trip completion rate). Adaptive driving increases fluctuations in the NFD; however, it reduces hysteresis and gridlock while increasing network capacity.

• Record URL:
  • https://doi.org/10.3141/2422-03
• Summary URL:
  • http://scholar.google.com/scholar_lookup?title=Dynamics+of+Urban+Network+Traffic+Flow+During+a+Large-Scale+Evacuation&author=A.+Zockaie&author=H.+Mahmassani&author=M.+Saberi&author=%c3.+Verbas&publication_year=2014
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/9780309295079
• Authors:
  • Zockaie, Ali
  • Mahmassani, Hani S
  • Saberi, Meead
  • Verbas, Ömer
• Publication Date: 2014

Language

• English

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 21–33
• Monograph Title: Traffic Flow Theory and Characteristics 2014, Volume 2
• Serial:
  • Transportation Research Record: Journal of the Transportation Research Board
  • Issue Number: 2422
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Dynamic traffic assignment; Evacuation; Network analysis (Planning); Traffic congestion; Traffic flow rate; Urban areas
• Uncontrolled Terms: Fundamental diagram
• Subject Areas: Highways; Operations and Traffic Management; Planning and Forecasting; Security and Emergencies; I71: Traffic Theory; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 01517552
• Record Type: Publication
• ISBN: 9780309295079
• Report/Paper Numbers: 14-1841
• Files: TRIS, TRB, ATRI
• Created Date: Mar 10 2014 9:24AM