Citation

Maher MJ, Hughes PC, Smith MJ, Ghali MO. Traffic Eng. Control 1993; 34(9): 414-419.

Copyright

(Copyright © 1993, Hemming Group)

DOI

unavailable

PMID

unavailable

Abstract

The research described in this paper has been aimed at the development of a methodology for the determination of system-optimising flow patterns in congested networks, when the objective function consists of a linear combination of network travel time and predicted accidents. The traffic model is a steady-state model and uses standard methods to estimate junction delays; the accident predictions are obtained through the use of the TRL junction accident models. The main feature of the objective function is its non-convexity, so that the 'terrain' over which the optimisation procedure searches has many local optima. In order to overcome this difficulty, the search is carried out from a number of starting points. Application of the methodology to some realistic test networks shows that, in general, there is scope for significant reduction in accidents (up to 25 percent in the networks used), at the expense of an increase in travel time. The work also shows how the form of the accident-minimising flow pattern can be used to construct a set of traffic management measures which, if applied, would have the effect of persuading drivers to adopt a routeing pattern similar to the accident-minimising pattern.