Estimating the Parameters of Cowan’s M3 Headway Distribution for Roundabout Capacity Analyses

Luís Vasconcelos, Ana Bastos Silva, Álvaro Seco, João Silva

Abstract


Capacity models based on the gap acceptance theory are widely used in unsignalised intersections and roundabout capacity analysis. These models are based on the statistical distribution of major vehicle headways. In this field, Cowan’s M3 distribution is usually recognized as the most adequate, but the estimation of its parameters is not trivial. In this paper, the main estimation methods are reviewed and a new method (Simultaneous Numerical Estimation – SNE) is proposed. The SNE method was used to develop a calibrated relation between parameters, using field data collected in Portuguese roads and roundabouts. It was determined that the new formula improves capacity estimates, either in one-lane or in two-lane roundabouts. The paper also addresses the importance of each input variable and parameter in the resulting capacity model, through a sensitivity analyses.


Keywords:

roundabout; capacity; Cowan M3; statistical distribution; sensitivity analyses; headway

Full Text:

PDF

References


Akçelik, R. 2006. Speed-Flow and Bunching Models for Unninterrupted Flow, in Proc. of the 5th International Symposium on Highway Capacity and Quality of Service. Transportation Research Board, Yokohama, Japan. ISBN 4905990610C3051.

Antov, D.; Abel, K.; Sürje, P.; Rõuk, H.; Rõivas, T. 2009. Speed Reduction Effects of Urban Roundabouts, The Baltic Journal of Road and Bridge Engineering 4(1): 22–26. http://dx.doi.org/10.3846/1822-427X.2009.4.22-26

Brilon, W.; Koenig, R.; Troutbeck, R. J. 1999. Useful Estimation Procedures for Critical Gaps, Transportation Research Part A: Policy and Practice 33(3–4): 161–186. http://dx.doi.org/10.1016/S0965-8564(98)00048-2

Çalışkanelli, P.; Özuysal, M.; Tanyel, S.; Yayla, N. 2009. Comparison of Different Capacity Models for Traffic Circles, Transport 24(4): 257–264. http://dx.doi.org/10.3846/1648-4142.2009.24.257-264

Cowan, R. J. 1975. Useful Headway Models, Transportation Research 9(6): 331–375. http://dx.doi.org/10.1016/0041-1647(75)90008-8

Hagring, O.; Rouphail, N. M.; Sørensen, H. A. 2003. Comparison of Capacity Models for Two-Lane Roundabouts, Transportation Research Record 1852: 114–123. http://dx.doi.org/10.3141/1852-15

Hagring, O. 1998. A Further Generalization of Tanner’s Formula, Transportation Research Part B: Methodological 32(6): 423–429. http://dx.doi.org/10.1016/S0191-2615(98)00010-1

Hagring, O. 1996. The Use of the Cowan M3 Distribution for Modelling Roundabout Flow, Traffic Engineering and Control 37(5): 328–332.

Luttinen, R. 1999. Properties of Cowan’s M3 Headway Distribution, Transportation Research Record: Journal of the Transportation Research Board 1678: 189–196. http://dx.doi.org/10.3141/1678-23

Mauro, R.; Branco, F. 2010. Comparative Analysis of Compact Multilane Roundabouts and Turbo-Roundabouts, Journal of Transportation Engineering 136(4): 316–322. http://dx.doi.org/10.1061/(ASCE)TE.1943-5436.0000106

Plank, A. W. 1982. The Capacity of a Priority Intersection – Two Approaches, Traffic Engineering and Control 23(2): 88–92.

Rodegerdts, L.; Blogg, M.; Wemple, E.; Myers, E.; Kyte, M.; Dixon, M. 2007. Roundabouts in the United States. NCHRP Report 572. Transportation Research Board, Washington, DC. ISBN 9780309098748.

Sullivan, D. P.; Troutbeck, R. 1997. An Exponential Relationship for the Proportion of Free Vehicles on Arterial Roads, Transportation Research Part A: Policy and Practice 31(1): 21–31. http://dx.doi.org/10.1016/S0965-8564(96)00013-4

Tanner, J. C. 1962. A Theoretical Analyses of Delays at an Uncontrolled Interserction, Biometrika 49(1–2): 163–170.

Tanyel, S.; Yayla, N. 2003. A Discussion on the Parameters of Cowan M3 Distribution for Turkey, Transportation Research Part A: Policy and Practice 37(2): 129–143. http://dx.doi.org/10.1016/S0965-8564(02)00009-5

Troutbeck, R. 1997. A Review on the Process to Estimate the Cowan M3 Headway Distribution Parameters, Traffic Engineering and Control 38(11): 601–603.

Vasconcelos, A.; Seco, Á.; Silva, A. B. 2009. Accessing the Impact of Quantification Errors in Traffic Simulation Models, in Proc. of the Applied Simulation and Modelling. Palma de Mallorca, Spain.

Zhang, G.; Wang, Y.; Wei, H.; Chen, Y. 2007. Examining Headway Distribution Models Using Urban Freeway Loop Event Data, TRB 2007 Annual Meeting. TRB, Washington, DC. http://dx.doi.org/10.3141/1999-15.




DOI: 10.3846/bjrbe.2012.35

Cited-By

1. Pedestrian Traffic Operations in Urban Networks
Yinan Zheng, Lily Elefteriadou, Thomas Chase, Bastian Schroeder, Virginia Sisiopiku
Transportation Research Procedia  vol: 15  first page: 137  year: 2016  
doi: 10.1016/j.trpro.2016.06.012

Refbacks

  • There are currently no refbacks.


Copyright (c) 2012 Vilnius Gediminas Technical University (VGTU) Press Technika