Wild Animal Road Mortality and Mitigation

Road networks cause the deaths of millions of wild animals annually. Effective mitigation measures exist but are inconsistently implemented. Understanding the evidence supports better infrastructure policy.

Key Facts

Road mortality is estimated to kill over 1 million vertebrates per day in the US alone; globally the figure is many times higher
Badgers, hedgehogs, barn owls, otters, and deer are among the most road-killed species in the UK, with some populations experiencing road mortality as their primary mortality cause
Wildlife crossing structures including underpasses, overpasses, and culverts reduce road mortality by 80-97% at properly fenced and designed sites
Hedgehog populations in the UK have declined by approximately 50% since the 1990s; road mortality is identified as a key contributing factor
Speed reductions and wildlife warning signs have modest effects alone; physical crossing structures combined with fencing are the most evidence-based solution

Welfare Considerations

Road mortality causes immense but largely invisible welfare harm to wild animals. Vehicle strikes are rarely instantly fatal — injured animals commonly die slowly from trauma, and injured adults leave dependent young to starve. The suffering is diffuse and geographically dispersed, making it easy to overlook compared to more visible threats. The evidence base for mitigation is strong: wildlife crossing structures, properly designed and fenced, dramatically reduce mortality at known hotspots. The barrier to implementation is political and economic — crossing structures are expensive and require cross-agency coordination between transport authorities and conservation bodies. Making wildlife-sensitive road design a standard requirement in infrastructure planning rather than a post-hoc addition would significantly reduce road-mortality welfare impacts across affected species.

What You Can Do

Report wildlife road mortality hotspots to local transport authorities and conservation organisations
Reduce driving speed at dawn and dusk when wildlife movement is highest, especially on rural roads
Support campaigns for wildlife crossing structures and underpasses at known animal crossing points
Advocate for wildlife road casualty monitoring programmes to guide infrastructure mitigation priorities
Create or maintain wildlife corridors in your garden to enable safer movement away from roads