This article presents an approach to the understanding of road accidents, one of main problems of modern cities, through the construction of a computer tool to calculate accident risk maps, called ROARMG (Road Accident Risk Maps Generator). The objective is to support the definition of mitigation actions and their scope by highlighting areas or roads sections that deserve greater attention. The application architecture is also described, which may serve as a guide for the development of further applications and strategies allowing a better understanding of road accident phenomenon.