Background Speeding is responsible for countless traffic collisions and road traffic injuries (RTIs) around the world. It threatens the lives of passengers in motor vehicles as well as the safety of other individuals sharing the public roads. Little evidence has been provided by low- and middle-income countries on speed transgression patterns.

Objective To document the prevalence of speeding in motor vehicles with four or more wheels and to analyse the associated factors in four Mexican cities.

Methods We conducted a cross-sectional study in the cities of Guadalajara-Zapopan, León, Cuernavaca and Villahermosa. Data on speed, drivers, vehicles, road infrastructure and the environment were collected from a randomly selected sample of urban road segments. We identified the factors associated with speeding through a logistic multiple regression model.

Results With an overall prevalence of 47% (95% CI 45.83 to 48.18), speeding occurred most frequently in Villahermosa (61.07%, 95% CI 59.10 to 63.01) as compared to León (51%, 95% CI 48.07 to 53.92), Cuernavaca (47.6%, 95% CI 45.35 to 49.85) and Guadalajara-Zapopan (20.76%, 95% CI 18.75 to 22.88). Speeding increased in the afternoons, on roads with numerous lanes, on Thursdays and Sundays and in foggy weather, but decreased in cities with speed control strategies and on roads with low visibility. No differences were observed between sexes or among age groups.

Conclusions Evidence from our study highlights the urgent need to implement speed control measures such as changes in road infrastructure and design, and to promote comprehensive speeding legislation aimed at reducing exposure to this important risk factor.