Space, Money, Life-stage, and the Allocation of Time

Allocation of time to various activities is known to be a function of various demographic, socio-economic, seasonal, and scheduling factors. This paper examines those variables through exploration of the 1990 Nationwide Personal Transportation Survey, which has been inverted to track activity durations. The data are examined in single and multi-variate contexts. Two key issues are considered. First, to what extent does activity duration influence travel duration after controlling for activity frequency. This is tested with a set of models explaining travel duration. The data show activity duration does have positive and significant effects on travel duration, supporting recent arguments in favor of activity based models. Second, which is a more important effect in explaining the large changes in travel and activity patterns over the past thirty years accompanied by the increase in female labor force participation, the loss of discretionary time due to work, the change in metropolitan location, or the rise in per capita income. To examine this second question more rigorously, a choice model is constructed which examines both the decision to undertake an activity and the share of time within a 24 hour budget allocated to several primary activities: home, work, shop, and other activities. The utility functions for the activities are comprised of demographic, socio-economic, temporal, and spatial factors. The data also suggest that income and location have modest effects on time allocation compared with the loss of discretionary time due to working.