Background Motor-vehicle collisions are a leading cause of child bicyclist and pedestrian injuries in Canada. Injury occurrence and severity are associated with vehicle speeds but may be moderated through traffic calming. As a third of child bicyclist and pedestrian injuries occur within 300 meters of schools, it is important to focus interventions at these locations. This study will compare the effect of two traffic calming measures (i.e., in-street signs and traffic-calming-curbs) around elementary (K-Gr8) schools in Calgary.

Methods Using a stepped-wedge cluster randomized controlled trial, 70 eligible elementary schools will be randomly assigned one traffic calming intervention, installed between April and August 2020. Traffic speed and volume (pneumatic tubes), and active transportation prevalence (observational counts), will be collected one week before and one week after intervention installation. Change in outcomes between pre- and post-intervention will be compared within schools for each intervention type. Post-intervention data will also be compared with pre-intervention data from schools yet to receive the intervention. Analyses will include generalized linear mixed effects models.

Results Reductions in vehicle speeds are expected for both traffic calming features. Smaller changes in traffic volume and active transportation are expected across all traffic calming features. Greater effects are expected from traffic-calming-curbs.

Discussion Scientific evidence on traffic calming intervention effectiveness may improve municipal decision-making, standards for new construction, prioritization of interventions in other jurisdictions, and inform further study in non-school environments. This study is a partnership between the City of Calgary and the University of Calgary.