Repetition and Variability in Urban Travel

Most travel models and theories assume the existence of habitual behavior, yet few empirical studies have examined the question of how much repetition or variability characterizes daily travel. We first review the arguments for expecting both repetition and variability in urban travel‐activity patterns and then conduct an empirical analysis of repetition and variability in travel over a five‐week period. The results show that, whereas many behaviors that make up the daily pattern are highly repetitious (they occur with high frequency over the 35 days), the similarity between daily travel patterns on different days in an individual's longitudinal record is quite low. Even the day that is the most typical of the individual's travel is a poor indicator of that person's overall travel pattern. Moreover, we found that each person generates several archetypical daily patterns over 35 days, and this finding has important implications for data collection and modeling in studies of urban travel.