Citation

Troutbeck RJ. Transp. Res. Rec. 1993; 1398: 54-60.

Copyright

(Copyright © 1993, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

The technique for estimating the capacity of traffic circles in Australia has employed a gap-acceptance approach. For this approach the influence of heavy vehicles was essentially ignored because the sites were typical and had about 5% heavy vehicles. The parameters used to quantify the gap-acceptance behavior of drivers had included the behavior of the heavy-vehicle drivers. The use of this technique has now been extended beyond a simple analytical process and is incorporated into the SIDRA analysis program. The consequences of including a high proportion of heavy vehicles needs to be estimated. The passenger car unit (pcu) technique for estimating the influence of heavy vehicles and another technique using three factors to modify the gap-acceptance parameters for drivers of heavy vehicles and drivers accepting a gap just ahead of a heavy vehicle are discussed. In both cases an analytical assessment was done. Values for these terms, which modify the gap-acceptance parameters, are evaluated from field studies and are reported. It was concluded that the pcu method is reasonable but that the modified gap acceptance approach provides greater understanding and flexibility. The values found will assist others in evaluating the influence of heavy vehicles at traffic circles and unsignalized intersections.

Record URL:
http://onlinepubs.trb.org/Onlinepubs/trr/1993/1398/1398-008.pdf

Language: en

Keywords

Mathematical models; Traffic control; Traffic signals; Computer simulation; Highway service areas