Average impact and important features of onboard eco-driving feedback: A meta-analysis.

• Onboard eco-driving feedback improves fuel economy by 6.6% on average. • The impact of most onboard feedback tested to-date deteriorates over time. • Eco-driving feedback should include both fine- and course-grained information. • Eco-driving feedback should include performance standards. • Multimodal eco-driving feedback may be more effective than visual only. • Gamification may enhance eco-driving feedback effectiveness. • Interventions should combine eco-driving feedback with education and rewards. Eco-driving refers to suites of behavior a driver can engage in to improve fuel economy. The most common strategy used to promote eco-driving is onboard feedback that conveys information about fuel efficiency to the driver. This paper presents a statistical meta-analysis of eco-driving feedback studies in order to determine a weighted estimate of the average impact of feedback on fuel economy and explore potential moderators of its effectiveness, particularly regarding features of the feedback interface design. The main effect of onboard feedback on fuel economy across the final sample of 17 studies and 23 effect sizes was 6.6% improvement. Feedback that included information about both instantaneous and accumulated performance predicted larger effects. Though not statistically significant, trends in relationships between other feedback design features and fuel economy outcomes aligned with study hypotheses. Length of feedback intervention negatively related to effects, and pairing feedback with instructions or rewards predicted larger effects. [ABSTRACT FROM AUTHOR]