An Analysis of Urban Travel Times: a Random Parameters Hazard-based Approach

The traditional approach to urban travel analysis includes a detailed and complex modeling system that considers activity/trip generation (including time-of-day of trip) and destination, mode, and route choices. While the insights that one can gain from such a comprehensive approach are undeniable, a more simplistic approach that focuses on travel time alone (which by its nature will implicitly include the complex decision-making related to destination, route, activity and time-of-day choices), can also provide valuable information for policy makers into the determinants of congestion, the behavior and destination choices of travelers, and so on. However, in such an approach, the unobserved heterogeneity that is introduced by simplifying a complex decision-making process must be addressed. In this paper, the determinants of travel time-to-destination for an urban area are studied while explicitly accounting for unobserved heterogeneity using hazard-based duration models with random parameters. Using an extensive geocoded trip dataset from Athens, Greece, time-to-destination model estimation results indicate that travel time duration is significantly affected by a number of factors such as sociodemographic and trip characteristics, travel mode, frequency of trip, and time of day of the trip. In addition, the effect of many of these factors was found to vary across the population, thus underscoring the need for using a random-parameters formulation in studying urban travel times with this approach.