Variability versus stability in daily travel and activity behaviour. The case of a one week travel diary

Temporal rhythms in travel and activity patterns are analysed thanks to a seven-day travel diary collected on 707 individuals in the city of Ghent (Belgium) in 2008. Our analysis confirms the large level of intrapersonal variability whether for daily trips, home-based tours, time use and activity sequence. However our analysis goes further by studying this variability along various time periods within the week. Moreover, we show that the systematic day-to-day variability has an extremely low share in intrapersonal variability. The influence of socio-demographic characteristics on intrapersonal variability is weak, whether for daily trips, tours, time use and activity sequence. Repetitive activity-travel behaviour is then detected, through attributes of activity at trip destination, travel mode, trip arrival time and destination location. The picture is at the same time one of diversity and of specificity in activity-travel across the week. People tend to concentrate their weekly activity-travel patterns on few combinations of attributes, despite a large dispersion. Our results on core stops are somewhat encouraging by showing some kind of concentration of activity patterns on a few "anchor" points.