Question One: Why do rich people commute longer distances than poor people, after all they have a higher value of time (and time is the scarcest of all commodities).
Manitoba or Manhattan
The Access to Destinations Conference, which I helped organize was just completed. It brought together 30 researchers from 5 continents to discuss the theory and practice of questions related to Accessibility. Accessibility is a measure of the ease of reaching destinations, and is contrasted with mobility, which simply measures the ease of use of the network. Accessibility and congestion and related phenomena, but not identical. The ability to move faster on the network generally improves both accessibility and congestion. However, accessibility accounts for land use, while mobility measures don’t. Manitoba is an example of a place with no congestion, and very low accessibility. Manhattan, on the other hand, has a great deal of congestion and a slow network, but also a great deal of accessibilty, many places can be reached in a very short time.
A book with the proceedings should be out in 2005.
David Gillen and David M. Levinson are pleased to announce the publication of Assessing the Benefits and Costs of Intelligent Transportation Systems
Levinson, David and Ajay Kumar (1994) The Rational Locator: Why Travel Times Have Remained Stable. Journal of the American Planning Association, Summer 1994 60:3 319-332.
This paper evaluates household travel surveys for the Washington metropolitan region conducted in 1968 and 1988, and shows that commuting times remain stable or decline over the twenty year period despite an increase in average travel distance, after controlling for trip purpose and mode of travel. The average automobile work-to-home time of 32.5 minutes in both 1968 and 1988 is, moreover, very consistent with a 1957 survey showing an average time of 33.5 minutes in metropolitan Washington. Average trip speeds increased by more than 20 percent, countering the effect of increased travel distance. This change was observed during a period of rapid suburban growth in the region. With the changing distributional composition of trip origins and destinations, overall travel times have remained relatively constant. The hypothesis that jobs and housing mutually co-locate to optimize travel times is lent further support by these data.