Urban and travel changes in the Greater Toronto Area and the transferability of trip-generation models

This paper discusses the important urban and travel changes in the Greater Toronto Area between 1964 and 1986, and reports the findings of a study into the temporal transferability of home-based trip generation models, estimated on 1964 data; and applied in prediction on 1986 survey data. Changes in urban structure include: a decline in average household size; decentralisation in population and employment; a change in household composition, reflected by an increase in the following: number of working members, household-vehicle ownership, and number of household-members licenced to drive; an increase in the average number of trips made per person and per household, notwithstanding the decline in average household size; an increase in car-use and a decline in the average vehicle occupancy. Disaggregate measures of transferability indicate the transferred 1964 home-based trip production models provide some useful information on trip-making in 1986. Regional forecasts, however, show most 1964-models have significant prediction bias, particularly for non-work-trips. Poor transferability of 1964 non-work trip-production models is not entirely attributable to transfer-bias.