A Generalized Model for Analyzing Operational Conditions at Intersections in Urban Areas

Lots of urban intersections are characterized by geometric and functional features such as to disprove their operational analysis through usual models based on gap-acceptance theory. This can be observed both for unsignalized intersections where the priority rule is given to cars coming from the right and for roundabouts where the priority rule is assigned to the circulating vehicles. The operational conditions in the urban context furthermore are affected by a strongly random component due to unconventional users behaviours, i.e. users giving their priority, or users entering into the intersection and ignoring the give-way sign. Based on these considerations the authors deem that performances of urban atypical intersections can be established only through a theoretical-empirical approach that puts in a fair equilibrium the need both to match field observations and to have a general criterion of performance analysis. In this paper an example of such an approach is shown for multilane-large diameter not-conventional roundabouts (MLLD roundabouts) for which a pattern of a consensus of right-of way – similar to all-way-stop-controlled intersections (AWSC intersections) – was observed. The complexity of the approach for these intersections is evident when one also considers that behavioral parameters necessary to develop the model are difficult to be observed. For this purpose, macroscopic observations of operational conditions are used in a regression model in order to provide the unknown behavioral parameters; the presence of response correlation within a cluster of observations has required the development of a marginal model, i.e. to estimate the unknown parameters through Generalized Estimating Equations (GEEs).


  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; References; Tables;
  • Pagination: 14p
  • Monograph Title: 3rd Urban Street Symposium: Uptown, Downtown, or Small Town: Designing Urban Streets That Work, June 24-27, 2007, Seattle, Washington

Subject/Index Terms

Filing Info

  • Accession Number: 01091667
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Mar 28 2008 10:37AM