In the 1989 Conference a paper was presented describing the methodology of a study investigating drivers' reactions to road pricing in the Western Netherlands (see IRRD 839282), together with some preliminary results. The study is now complete, and, as well as implementation in a full scale travel forecasting model, the model has been implemented as a policy testing tool. The aim of the policy testing tool is to predict to what extent drivers would be prepared to switch within the peak two hour period, or to the shoulders of the peak. Considerable variation in behaviour was detected in the Stated Preference data, in terms of drivers' reluctance to shift their time of travel forwards or backwards in time. Factors contributing were: journey purpose, nature of constraints on arrival or departure, and current time of travel with respect to the 'peak within the peak'. In addition, as expected, there was a strong income effect in the reaction to cost, though the effect of income was appreciably less for afternoon travellers. The results of this behavioural analysis of the data have been incorporated into an application module, using the spreadsheet- like JAVELIN system. This allows the user to input a policy (which as well as specifying the level and duration of the road pricing charge also allows some global changes to public transport service), and predicts the changes in time of travel and mode. The module makes use of sample enumeration, but also incorporates a feedback effect in the form of a simple speed-flow relationship, so that the changing volumes by time of day influence journey time: the model can iterate to convergence. The paper will give the details of the behavioural analysis, and describe the operation of the application module, as well as demonstrating the predicted sensitivity of behaviour to pricing and other changes.
Abstract