Wednesday, November 15, 2023
8:30 AM - 10:00 AM
From Naifs to Sophisticates: Awareness of Self-nudging Reduces Car Usage
Session ID
A7 - Lightning: Transportation

Making public transportation attractive, together with strict car ownership and usage curbs, are core features of Singapore’s transportation policy. While such measures have been effective at maintaining a low car mode share, this study seeks to understand if a complementary self-nudge-based approach, without any use of incentives and disincentives, could achieve further car use reduction. The central idea of our intervention is to progress behavioral naifs to sophisticates by exposure to nudge ideas labeled as Plan, Distance and Celebrate (PDC). “Plan” urged participants to consider pre-planning their car-free days in a virtual calendar and then to pin it in a visible location. “Distance” encouraged participants to consider introducing friction between themselves and their car or car keys, such as by “leaving car keys in a bag of rice”, to hopefully disrupt the car use habit. Finally, “Celebrate” sought to make small wins psychologically rewarding by alerting participants to habit tracking apps that could provide engaging, instantaneous encouragement for each day of car abstinence. Participation in these nudge strategies was not required to successfully complete the study. In a 3-week randomized controlled trial involving around 500 Singapore car owners, for whom we have car entry-exit records at their home parking lot, we find that among participants who reported some initial intention to reduce car use, exposure to our PDC program induced an average of 0.6 fewer exits per week from home parking lots than the control group. The nudgeability of car owners to our intervention could be explained in part by the transtheoretical model of change, with self-assessed “grudging car users” and “procrastinators” exhibiting a reduction of up to 30% in exits relative to “contented car captives”. Our results make the case for a scaled up PDC program, which can be easily made permanent since it is inexpensive to implement.

Supporting Document 1