Roads kill tens of millions of wild mammals annually in Europe and North America. Understanding road mortality patterns enables targeted mitigation to reduce this massive source of animal suffering and death.
Road mortality causes an enormous and largely invisible welfare toll on wild animal populations. The deaths themselves — collision impacts, being struck at speed — cause acute traumatic injury. Animals that are not killed outright may lie injured at roadsides for hours before dying or being found. Cubs, pups and joeys of killed females frequently die slowly from starvation and exposure. The population-level effects of road mortality intersect with welfare at the population scale: declining hedgehog and otter populations mean fewer animals experiencing positive welfare states in functional wild habitats. Mitigation exists and works: wildlife crossing structures with appropriate guiding fencing dramatically reduce mortality at targeted points. The challenge is prioritization — installing crossings where they will benefit most animals of highest population concern — and maintenance, since fencing that degrades becomes a trap rather than a guide. Reduced vehicle speeds in known wildlife crossing areas represent the most broadly applicable intervention available to individual drivers.