Background The Bloomberg Initiative for Global Road Safety (BIGRS) is a partnership between international organizations and local governments to implement evidence-based interventions to improve road safety (Bloomberg Philanthropies 2018). From 2015–2019, BIGRS took place in ten selected cities in nine countries, aiming to identify and evaluate effective road safety interventions in low- and middle-income countries.

Objective To characterize the city-wide prevalence of speeding, drunk driving, helmet use, and seatbelt use in three Latin American cities, Bogota, Sao Paulo, and Fortaleza, from 2015 to 2019.

Methods In partnership with local universities, we conducted eight rounds of data collection per risk factor. We collected information about the driver (sex, approximate age, and the use of seatbelt or helmet), the motor vehicle (number of passengers, type), and the observation sites (date, weather conditions, start and end time, lanes) using standardized data collection protocols. We used STATA 15 to calculate each city’s summary measures (frequencies and percentages) per round.

Results We observed 1,982,423 vehicles for all Bogota, Sao Paulo, and Fortaleza risk factors. Across cities, Fortaleza had the most substantial increase in overall seatbelt and helmet-wearing rates among all sites, and Bogota had the largest decrease in speeding. Similarly, across cities, the prevalence of child restraints and seat-belt use in back seat passengers was very low (30% and 10%, respectively).

Conclusions Fortaleza is a model to follow to improve road safety risk factors. However, this city had a higher starting prevalence of all risk factors than others. This could partly explain the faster rate of risk factor improvement when the city implemented measures to improve road safety.