Driving change: A scoping review of psychological interventions to reduce engine idling and air pollution

Emissions from stationary vehicles (i.e., engine idling) are a major contributor to air pollution, a serious environmental issue that also threatens physical and mental health. Engineering and technical sciences focus on tackling idling pollution through technological advancement but they mostly ignore the human factor (the vehicle driver). In contrast, psychological science has proposed and tested human-centered interventions aiming to influence drivers’ behavior directly. Despite their crucial potential to inform strategies for improving public health, these tests have been relatively scarce and dispersed across time and place. Here we conduct a systematic literature search adhering to the PRISMA 2020 guidelines to establish a scoping review of behavior change interventions to reduce engine idling. A search of the Web of Science, Scopus, and PsychINFO databases yielded 26 relevant studies: 11 relying on individual training, 3 on feedback, 5 on community-based interventions, and 7 on psychological messaging. The review suggests that individual training may be effective but mostly in the short-term, with less systematic effects appearing in the longer term. Providing feedback on driving is also an effective approach, especially when used to signal undesirable behavior (i.e., via negative feedback). Community-based interventions emerge as a costly but effective approach, when they succeed to engage community members. Finally, theory-led psychological messaging may be especially effective but message content is key and not every message yields effects. The review summarizes the findings of the existing research, highlights strengths and limitations, and provides future research directions for efficient ways of tackling engine idling.