Dimension	Criteria
(1) Selection and matching of intervention and control areas	The characteristics of the study and control sites were the same/similar There were no changes in the control sites during the study period The control sites were not adjacent to the intervention sites
	It is unlikely that the control group received the intervention
(2) Blinding of data collection and analysis	The outcome data were obtained from routine reporting systems (not originally collected for study) The analysis was conducted blind to intervention and control groups
(3) Lengths of data collection time period pre‐ and post‐intervention	Length of before period is at least 1 year Length of after period is at least 1 year
(4) Reporting of results	The main findings of the study are clearly described The authors report uncertainty due to random variability (confidence intervals) Appropriate statistical tests were used to assess the main outcomes reported (p‐Values)
(5) Control of confounders	The authors describe potential confounders The distributions of confounders in intervention and control sites were assessed and similar Do the authors discuss the effect of confounders on the results?
(6) Any other potential sources of bias	Did the study control for potential bias due to regression to the mean? Did the study report, or control for “spill‐over” effects (e.g., use control sites located away from red light camera sites and associated publicity)? Were any other sources of bias addressed?