Comparison of homogeneous and heterogeneous motorised traffic at signalised and two-way stop control single lane intersection

Results of a microscopic model of mixed motorised traffic consisting of short vehicles, (e.g. cars), and long vehicles, (taken to be double the length of the short vehicles), for an urban two-way single lane intersection are presented here. We model the intersection using both signalised and un-signalised stop control rules. The model allows for the detection of bottleneck activity in both homogenous and heterogeneous traffic conditions, and was validated by means of field data collected in Dublin, Ireland. The validated model was used to study the impact of inclusion of long vehicles on traffic performance in an urban environment. Traffic mix is, however, taken to be dominated by short vehicles overall, in argument with observed live data collected

Issues with the operational analysis of urban intersections

Paper presented at the 23rd Annual Southern African Transport Conference 12 - 15 July 2004 "Getting recognition for the importance of transport", CSIR International Convention Centre, Pretoria, South Africa. Operational analyses of urban intersections are often undertaken during traffic impact studies to evaluate the impact of a development on traffic flow. Many improvements to the urban street network are often warranted on the basis of such analyses. Various studies have, however, been undertaken in South Africa and Australia that show that the operational analysis of an intersection is a complex exercise which often produces invalid results. The studies have shown that a large number of factors need to be taken into account when modelling urban intersections, and that the models should be properly calibrated and validated. Unless these issues are properly addressed, the operational analysis of intersections serves little or no purpose. In this paper, it is proposed that simpler approaches should be utilised for the purposes of traffic impact studies. One relative simple approach that can be considered is to evaluate intersections simply in terms of volume/capacity ratios. Improvements to the street network can then be warranted on the basis of such ratios. Maximum ratios for such purpose are proposed in the paper.This paper was transferred from the original CD ROM created for this conference. The material on the CD ROM was published using Adobe Acrobat technology. The original CD ROM was produced by Document Transformation Technologies Postal Address: PO Box 560 Irene 0062 South Africa. Tel.: +27 12 667 2074 Fax: +27 12 667 2766 E-mail: [email protected] URL: http://www.doctech.co.z