J. de D. Ortúzar

Modelling new pricing strategies for the Santiago Metro

After twenty years of operation the Santiago Metro decided to start a new strategy of price differences by period in order to decrease congestion in the morning peak and to postpone the acquisition of new equipment. In this paper we report the results of a model specifically designed to test the impact of different price levels on patronage by period. Stated preference (SP) data was collected, focusing on three aspects: change in time of travel, price differences and comfort improvements. A goods-leisure microeconomics framework was adopted to decide on users segmentation and model specification. Two methodological aspects were explored, the non-linear marginal valuation of time displacements and the different known ways to analyse SP rating experiments. In this quest, models were calibrated both with a standard and an optimal probabilistic interpretation of the semantic scale and with the ordinal probit and binary logit models. Comparisons were made and conclusions reached about the more appropriate approach. Finally, the current time-of-day pricing strategy of the Santiago Metro, which commenced operation in February 1994, was simulated using the best models reported in the paper. This was done in order to test their validity against an observed reality.

FLEXIBLE LONG RANGE PLANNING USING LOW COST INFORMATION

Contemporary transport planning requires a flexible modelling approach which can be used to monitor the implementation of a long term plan checking regularly its short term performance with easily available data; the original model is periodically updated using low cost information and this allows the evaluation of the changes to the plan which may be required. Such an approach requires models suited to regular updating and to the use of data from different sources. Models to update trip matrices from traffic counts have been available for some time; however, the estimation and/or updating of other model stages with low cost data has escaped analytical treatment. The paper discusses this idea and formulates the updating problem for an example involving a joint destination/mode choice model under various assumptions about the nature of the available data. Analytical solutions are proposed as well as some general conclusions.

ON THE STABILITY OF DISCRETE CHOICE MODELS IN DIFFERENT ENVIRONMENTS

The question of transferability of models in time and place is a point of frequent debate among transport planning practitioners. Using the same model structure and two different data sets from Leeds, England and Santiago, Chile, the authors examine the transferability of a multinomial logit modal choice model. The findings of the research indicated that the hypothesis of transferability cannot be supported in this case. A preliminary version of this paper was presented to the 1983 World Conference of Transport Research, Hamburg.