Animals may escape and die away from the road after the collision, rebound off the road or retain by vehicle. In these cases, it is so extremely difficult to be recorded through typical roadkill surveys. The study has been carried out by the Doñana Biological Station within the SAFE project to assess wildlife mortality on Spanish roads

? SAFE is a citizen science project aiming to quantify the number of animals killed in roads every year, determine which species are most affected and detect the factors affecting this problem