A dynamic assignment/control model for evaluating urban traffic control schemes and route guidance strategies is described in this paper. The model, which has been developed recently at the University of York, United Kingdom, uses the dynamic assignment program CONTRAM. For each fixed road network, subject to a given overall pattern of dynamic demand, the model currently evaluates all eight possible combinations of (a) four responsive traffic control policies, and (b) two route-guidance strategies. The model assumes that the route-guidance is accurately obeyed. The model gives results for all required demand levels. Preliminary results of applying the model to one artificial network and one realistic network are also presented. Further extensions are in hand to take some account of (a) drivers' variable compliance with guidance, (b) the effects of different traffic signals following different control policies, and (c) drivers' ability to select their own departure time. At the moment, the model requires that the road network is fixed, and does not seek to mimic the dynamics associated with the beginning and end of an incident. Good communications with drivers will help to ensure that the guidance advice is obeyed; but for system-optimal-like guidance strategies a supportive, well-communicated, road pricing system may also be necessary to obtain such obedience. The model described here will clearly be useful for assessing the consequences of different road pricing strategies in a dynamic setting. This paper appears in Transportation Research Record No. 1306, In-vehicle Information Systems: modelling Traffic Networks and behavioural Considerations 1991.
Samenvatting