Date Published: April 11, 2019
Publisher: Public Library of Science
Author(s): Fernanda Delborgo Abra, Beatriz Machado Granziera, Marcel Pieter Huijser, Katia Maria Paschoaletto Micchi de Barros Ferraz, Camilla Mansur Haddad, Roberta Montanheiro Paolino, Sergio A. Useche.
Direct road mortality and the barrier effect of roads are typically identified as one of the greatest threats to wildlife. In addition, collisions with large mammals are also a threat to human safety and represent an economic cost to society. We documented and explored the effects of animal-vehicle crashes on human safety in São Paulo State, Brazil. We estimated the costs of these crashes to society, and we summarized the legal perspectives. On average, the Military Highway Police of São Paulo reported 2,611 animal-vehicle crashes per year (3.3% of total crashes), and 18.5% of these resulted in human injuries or fatalities. The total annual cost to society was estimated at R$ 56,550,642 (US $ 25,144,794). The average cost for an animal-vehicle crash, regardless of whether human injuries and fatalities occurred, was R$ 21,656 (US $ 9,629). The Brazilian legal system overwhelmingly (91.7% of the cases) holds the road administrator liable for animal-vehicle collisions, both with wild and domestic species. On average, road administrators spent R$ 2,463,380 (US $ 1,005,051) per year compensating victims. The logical conclusion is that the Brazilian legal system expects road administrators to keep animals, both wild and domestic species, off the road. We suggest an improved coordination between the laws that relate to animal-vehicle collisions and human safety, and the process for environmental licenses that focusses on reducing collisions with wildlife and providing habitat connectivity. In addition, we suggest better management practices, raising awareness and social change with regard to abandoned domesticated animals including horses, cattle, and dogs. This should ultimately result in a road system with improved human safety, reduced unnatural mortality for both domestic and wild animal species, safe crossing opportunities for wildlife, and reduced monetary costs to society.
On a global scale, roads have important benefits for society as they allow for the transportation of people and goods. However, they also represent one of biggest threats to biodiversity , , . For animals, the effects of roads and traffic are varied and range from habitat loss , direct mortality through collisions with vehicles , , barrier effects ,  and a reduction in habitat quality in a zone adjacent to the road (e.g. noise, lights, pollution, visual disturbance) , , .
The crash data from the Military Highway Police of São Paulo State (PMRSP) showed that the number of reported animal-vehicle crashes are increasing and represent 3.3% of the total number of reported crashes in São Paulo State. This percentage is higher than the national crash data in Brazil (1.9%; ), but lower than the national crash data in the United States (about 4–5%; , ). An increase in traffic volume, new roads in remote areas, and increasing populations of species that adapt to living in agricultural and residential areas are all likely contributing factors to the increase of the reports.
Our study demonstrates that the number of reported animal-vehicle crashes and associated costs are increasing in São Paulo State. Animal-vehicle crashes with large animal species, wild or domestic, are dangerous to people, especially for occupants of light vehicles such as motorcycles. Interestingly, Brazilian law holds road managers responsible for animal-vehicle collisions. This suggests that road managers have the obligation to keep animals, wild and domestic, off the highway. We suggest a better coordination between the laws that relate to animal-vehicle collisions and human safety, and the process for environmental licenses that focuses on both reducing collisions with wildlife and maintaining or improving habitat connectivity. These actions should ultimately result in a road system with increased human safety, reduced unnatural mortality for both domestic and wild animal species, safe crossing opportunities for wildlife, and reduced monetary costs to society. Our analyses of animal-vehicle collisions in São Paulo State goes beyond the traditional perspective of road ecology papers that mostly focus on biological conservation. Our study is a first step to specifically address human safety, economic and legal issues associated with animal-vehicle collisions in Brazil. The results can be valuable in the decision process for the planning of the construction or reconstruction of roads. It would take human safety, wildlife, as well as monetary costs into account. We believe that this is better than accepting a continuing increase in animal-vehicle collisions, and associated impacts on human safety, economic parameters, and the environment.