From excess commuting to commuting possibilities: more extension to the concept of excess commuting

The excess-commuting literature provides a methodological framework in which the observed average commute (C-obs) is compared with theoretical commuting values: the minimum (C-min) and maximum (C-max) average commute. In this paper, I argue that real spatial behavior is ill represented by the two assumptions of optimal (minimizing or maximizing) behavior. C-min and C-max are in fact extreme values of a much richer distribution of commuting possibilities. I argue that all those possibilities should be taken into account in the evaluation of C-obs. In order to do this, I develop a probabilistic framework where any urban form is associated with a statistical distribution of commuting possibilities, with an average and a standard deviation, within which C-min and C-max represent extreme and very improbable outcomes. Applied to a sample of fifty metropolitan areas, this framework helps us understand the combined association of spatial behavior and urban form with commuting.