Wildlife Roadkill on Brazilian Highways: Ecological and Human Costs: Evidence from DNIT's 2026 Road Safety and Wildlife Conservation Report

Brazil harbors the world's greatest diversity of terrestrial mammals, with approximately 785 species, yet its extensive highway network poses substantial threats to wildlife and human safety through wildlife-vehicle collisions. This study assessed the ecological, public health, and economic impacts of wildlife road mortality using data from the National Department of Transport Infrastructure (DNIT) publication- Road Safety and Wildlife Conservation: Mitigation Measures to Reduce Impacts on Wild Animals on Brazilian Federal Highways (2026), complemented by records from the Federal Highway Police (PRF) and national wildlife monitoring databases. DNIT estimates that approximately 39,600 medium and large-sized wild mammals are killed annually on roads in São Paulo state alone. Nationally, the PRF recorded 3,174 animal-related traffic collisions in 2014, representing 1.9% of all reported highway accidents. In São Paulo, an estimated 2,611 wildlife-vehicle collisions occur annually, accounting for 3.3% of accidents, of which 18.5% result in human injuries or fatalities. The associated societal costs are estimated at R$56 million per year, including medical care, emergency response, vehicle and cargo removal, public services, and property damage. Beyond direct mortality, roadkill may compromise ecosystem functions by reducing seed dispersal, pest regulation, nutrient cycling, and pollination services. According to DNIT, 103 threatened mammal species are potentially affected by road mortality, including 51 species classified as highly sensitive to road impacts. Evidence presented by DNIT further indicates that mitigation measures such as wildlife crossings, fencing, and targeted signage can reduce collisions by up to 83%, generating favorable medium-term cost-benefit outcomes. Although these estimates are derived primarily from existing monitoring and administrative data, the findings highlight wildlife-vehicle collisions as a significant but often underrecognized environmental, economic, and public safety challenge in Brazil, supporting the integration of biodiversity conservation measures into transportation planning and environmental licensing processes.