No abstract

Abstract. This paper gives a detailed empirical analysis of the relationships between di¨erent indicators of costs of commuting trips by car: di¨erence as the crow¯ies, shortest travel time according to route planner, corresponding travel distance, and reported travel time. Reported travel times are usually rounded in multiples of ®ve minutes. This calls for special statistical techniques. Ignoring the phenomenon of rounding leads to biased estimation results for shorter distances. Rather surprisingly, the distance as the crow¯ies and the network distance appear to be slightly better proxies of the reported travel time compared with the shortest network travel time as indicated by the route planner. We conclude that where actual driving times are missing in commuting research the other three indicators mentioned may be used as proxies, but that the following problems may emerge: actual travel times may be considerably higher than network times generated by route planners, and the average speed of trips increases considerably with distance, implying an overestimate of travel time for long distance commuters. The only personal feature that contributes signi®cantly to variations in reported travel times is gender: women appear to drive at lower average speeds according to our data. As indicated in the paper this may be explained by the di¨erences in the car types of male and female drivers (females drive older and smaller cars) as well as higher numbers of stops/trip chaining among women. A concise analysis is carried out for carpoolers. Car-pooling leads to an increase in travel time of some 17% compared with solo drivers covering the same distance. In the case of car poolers, the above mentioned measures appear to be very poor proxies for the actual commuting times.

No abstract

No abstract

This paper aims to provide insights that help transport academics and policy makers appreciate the potentials and limitations of information provision as a means to changing car-drivers’ travel choices. The focus is on a modal shift from private car to public transport and changes in car-drivers’ choices for departure times and routes towards a more even distribution of traffic within the available road network. These insights are gained through a review of more than 15 years of literature concerning the use and effects of travel information among car-drivers. Based on the performed review, a number of generic, integrative insights are derived, including the following: it appears that our expectations with respect to the effects of information provision on travel choices in general may be mildly optimistic, particularly for behavioural changes not involving changes in mode-choice. In the longer term, the effects of information provision, when presented to travelers in suitable formats, are likely to be somewhat stronger than the short term effects, due to learning dynamics.