Competing risk hazard model of activity choice, timing, sequencing, and duration

Recently hazard models have become increasingly popular in transportation research for modeling duration processes of various kinds. The application of hazard models is extended to the field of activity scheduling to account for the continuous nature of the decision-making process underlying activity performance. A competing risk hazard model of the accelerated time type, which describes simultaneously the duration of the present activity and the choice of the next activity, is presented. Both a generic and an activity-specific version of the model were estimated. The covariates used in the model represent factors that affect activity scheduling, such as time of day, opening hours, travel times, priorities, and time budgets. An interactive computerized data collection procedure was used to obtain specific data needed to calculate the covariates. The estimated models performed satisfactorily, suggesting that competing risk models are a useful tool for describing activity scheduling as a continuous decision-making process. This is an important finding, especially because influencing the timing of activities and trips is a subject of increasing interest to policy makers.