Background Despite several global resolutions to improve road safety, road traffic injuries (RTI) have continued to grow in many countries, indicating gaps in evidence on intervention that work.

Method We developed an Evidence Gap Map (EGM) to identify existing evidence from all effectiveness studies and systematic reviews related to road safety interventions. Following Campbell Collaboration protocols, we searched in academic databases, organization websites, and grey literature sources up to December 2019. We classified interventions into five broad categories: human factors (e.g., enforcement or education); road design, infrastructure, and traffic control; legal and institutional framework; post-crash pre-hospital care; and vehicle factors (except those protecting vehicle occupants) and protective devices. Further classification included primary outcomes of fatal crashes and non-fatal injury crashes; and four intermediate outcomes of use of seat belts, use of helmets, speed, and alcohol/drug use.

Results The EGM identified 1859 studies of which 322 were systematic reviews, 7 were protocol studies and 1530 were impact evaluations. The distribution of available evidence is highly skewed across the world, with a vast majority of the literature from high-income countries. Evidence is limited for interventions that are of greater relevance to low-and-middle income countries (LMIC). A large majority of systematic reviews are of low quality.

Conclusion The scarcity of evidence on many important interventions and lack of good quality evidence-syntheses have significant implications for future road safety research and practice in LMIC. The EGM presented here will help identify priority areas for researchers, while directing practitioners and policy makers towards proven interventions.