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Transport planning relies extensively on forecasts of traveler behavior over horizons of 20 years and more. Implicit in such forecasts is the assumption that travelers' tastes, as represented by the behavioral model parameters, are constant over time. In technical terms, this assumption is referred to as the "temporal transferability" of the models. This paper summarizes the findings from a literature review that demonstrates there is little evidence about the transferability of mode-destination models over typical forecasting horizons. The literature review shows a relative lack of empirical studies given the importance of the issue. To provide further insights and evidence, models of commuter mode-destination choice been developed from household interview data collected across the Greater Toronto and Hamilton Area in 1986, 1996, 2001, and 2006. The analysis demonstrates that improving model specification improves the transferability of the models, and in general the transferability declines as the transfer period increases. The transferability of the level-of-service parameters is higher than transferability of the cost parameters, which has important implications when considering the accuracy of forecasts for different types of policy. The transferred models over-predict the key change in mode share over the transfer period—specifically, the shift from local transit to auto driver between 1986 and 1996—but under-predict the growth in commuting tour lengths over the same period.

This paper studies intertemporal changes in the value of travel time (VTT) and investigates whether the change of VTT over time can be studied based on national VTT data, collected at two points in time. We use repeated national VTT data from the Netherlands and Sweden, collected 13 and 14 years apart. The results show mostly a declining VTT for a given income level. The results show also a large within-country heterogeneity across modes and purposes, in the cross-sectional income elasticity of the VTT, and in its development over time. The explanation most consistent with our results and those of others is that the VTT has in fact increased due to income increases, but that the repeated stated choice data cannot detect this given the data, methodology and population changes. In particular, it seems that the response rate has dropped considerably in the later surveys partly due to a higher share of (busy) respondents declining to be recruited. The main contribution of this paper is to document the differences between the studies carried out in different years, indicating the reasons why it is difficult to identify temporal changes in the VTT. ; Funding Agencies|Swedish National Road and Transport Research Institute (VTI); Swedish governmental agency VINNOVA