  Ecodriving guidance includes courses or suggestions for human drivers to
improve driving behaviour, reducing energy use and emissions. This paper
presents a systematic review of existing eco-driving guidance studies and
identifies challenges to tackle in the future. A standard agreement on the
guidance design has not been reached, leading to difficulties in designing and
implementing eco-driving guidance for human drivers. Both static and dynamic
guidance systems have a great variety of guidance results. In addition, the
influencing factors, such as the suggestion content, the displaying methods,
and drivers socio-demographic characteristics, have opposite effects on the
guidance result across studies, while the reason has not been revealed. Drivers
motivation to practice eco behaviour, especially long-term, is overlooked.
Besides, the relationship between users acceptance and system effectiveness is
still unclear. Adaptive driving suggestions based on drivers habits can improve
the effectiveness, while this field is under investigation.
