Self-assessment of mobility behaviour: Quantifying the divergence between self-assessment and vehicle sensor data

Motorised individual mobility is associated with many negative externalities for the environment and society. However, before considering ways to change motorised individual mobility behaviour, it is important to understand how individuals assess their mobility behaviour. Motorised individual mobility is largely habitual, which reduces the cognitive involvement of individuals in decision making and may lead to biased self-assessments of mobility behaviour. This paper therefore aims to better understand the extent to which individuals are aware of their mobility behaviour. In particular, I compare the average self- assessments of 1026 Dutch BMW customers with the average sensor data of 7494 BMWs in the Netherlands on five items. The results show that individuals underestimate their car use for each item. While the largest divergence is for the proportion of short trips, the smallest divergence is for the number of active driving days per month. These findings can help in the design of optimised behavioural interventions by highlighting the need for deliberative nudges.