On actual carpooling behaviour: a nationwide study in Spain

Carpooling is a powerful tool to reduce the total number of car trips and associated CO2 emissions. Hence, factors influencing carpooling have been extensively researched. However, most studies have been limited in geographic scope, relied on low-quality surveys, and focused on declared intentions rather than actual behaviour. The current study used a well-designed, nationwide survey that captures actual carpooling behaviour. To estimate the impact of three novel variables: having a solar panel at home (a measure of eco-awareness), a fuel-effort indicator (a measure of the relative cost of filling a car fuel tank), and the degree of participation in social networks (a measure of social trust and tech savviness), we developed a binary logistic regression model adjusting for multiple control variables identified as relevant in systematic reviews. Our analysis confirmed the relevance of most control variables and showed all three variables had a significant effect on individuals' likelihood of carpooling. These findings imply that policies that are not originally intended to encourage carpooling could boost it indirectly.