Heterogeneity in departure time preferences, flexibility and schedule constraints

This study develops a latent class choice model of departure time preferences for morning commute trips by car. The model is empirically evaluated using a sample of car commuters (mainly) in the Greater Copenhagen region in Denmark. The model identifies three classes that differ in terms of their preferences for departure times, their schedule constraints and degree of flexibility, and their socio-demographics characteristics. Roughly 30% of the sample exhibits high flexibility and is quite willing to reschedule in response to ‘peak spreading’ travel demand management strategies; 50% of the sample is constrained in the afternoon and evening, and consequently, less responsive to these strategies; and 20% of the sample is constrained in the morning and afternoons, and least likely to reschedule. We demonstrate the value of our model framework for policy analysis over simpler choice model frameworks that do not explicitly account for the existence of population segments with distinct preferences for departure time behaviour. In particular, we demonstrate how forecasts from our model may differ substantially from corresponding forecasts from more conventional choice models.