Traffic reports (TR) about wildlife-vehicle collisions drafted by traffic safety authorities or the departments of transportation constitute a source of information only rarely taken into account in biological studies, but one that could be useful because it is constant, abundant, inexpensive, and has nearly complete territorial coverage in many parts of the world. To assess the usefulness of TR in species distribution for three European ungulate species (wild boar, roe deer and red deer) we compared the spatial distribution in a 10× 10 UTM grid square (cells) obtained using TR with their distribution described in the Atlas and Red Book of Spanish Terrestrial Mammals (ARBSTM). The study was carried out in north-central Spain. The results show that TR offers a good complement to the data sources from the ARBSTM, contributing to new distribution sites in insufficiently sampled areas. The average increase in areas inhabited by the species studied was 41.52%. However, TR cannot be used as the sole source of information. Thus, for 35.16% of the positive cells reflected in the ARBSTM there were no reported roadkills. In the mountainous periphery of the study area, with higher population densities of ungulates, the TR method was as good as those used in the ARBSTM in cells with medium road density, but was unable to detect the presence of wildlife in zones with low road density. The repeatability across time in roadkills using TR increased with the level of development of the road network and the percentage of area suitable for the species.