Background Traffic accident remains being one on the broader challenges in LMIC. In addition, persistent social inequalities for this cause have been found in several settings. In a previous study we found traffic accident to be one of the major source of overall inequality for adult (25–64 years) mortality for both men and women in Colombia. Nevertheless we did not properly examine trends or differences by age, and how this event toll on senior population in which rates are usually larger than in other age groups. In this paper we aim to explain how evolve these inequalities in adult mortality by traffic accident by educational level among adult (25+ years) men and women from 1998 to 2015.

Methods Data from national adult mortality by traffic accident registries were linked to population censuses to obtain adult mortality by traffic accident rates by educational level. We used Poisson regression to model trends in adult mortality by traffic accident by education using the Relative Index of Inequality (RII).

Findings Similar to other settings, we found in Colombia a recent steady decrease in traffic accident mortality rates. Nevertheless a stop in this reduction was found from 2011 onwards. Nevertheless we found that those reductions remain up to the final of the period in age and educational groups less affected by the event: Women, youngest adults (those aged 25–44), and those who accessed to tertiary education. These trends led to a growing inequality in mortality by traffic accident, that take a largest toll among unfavoured but also in senior population and men, the most affected groups. Interpretation The striking contribution of adult mortality by traffic accident to socioeconomic differences in adult mortality by traffic accident became even worst and more pronounced among senior adult men. There is a need for social policy approaches that address the differences in the what that different sex, educational and age groups address the risk of traffic events.