Wildlife-Vehicle Collisions and Mitigation

Disease -> anything that makes you unwell

Background

• Over 1 million collisions annually 

  • Cause mortality in almost 25,000 animals and 200 people each year 

• 51,522 WVC recorded in TX between 2010-2016

  • Most in rural roads, high speed limits 

  • Leading cause of mortality for Ocelots in South Texas 

    • Most likely occurred during dawn and dusk hours 

• Some species cross roadways during daily pursuit of meals 

  • Grey squirrels, white-tailed deer

• Others only cross during migration 

  • Mule deer, Pronghorn, Black bears, Moose

Mitigation History

• Infrastructure Investment and Jobs Act of 2021 

  • Federal Highway Administration created Wildlife Crossing Pilot Program

  • $125 million in grants during FY24-25

• Lead to increased construction of wildlife crossing structures

  • Create habitat corridors to connect one side of the road to the other 

• Used for a variety of species 

  • Terrestrial and aquatic

Tools for Mitigation

• Structures include:

  • Underpass/Wildlife benches 

  • Tunnels 

  • Culverts 

  • Overpasses/Ecoducts 

  • Drift fences 

  • Fences 

  • Cattle guards

  • Animal Detection systems

• Used individually or in combination

Underpasses

• Can include wildlife benches 

  • Allows animals to cross even during periods of flood 

• Often paired with fences to prevent animals from getting onto roads 

• Range in price from $500,000 to $2.7 million 

• Utilize game cameras to conduct studies to monitor usage and effectiveness

• Limit light, can make it more difficult for bats and birds and other species to use

Tunnels

• Habitat is continuous from one side of the roadway to another 

• Largest crossing structure allowing the widest variety of species 

  • Minimum: 230 ft wide 

• Can be single or double tunnel 

• Often cut through mountains or hills 

• Also known as landscape bridges 

• More used to connect the habitat and they provide a flyover guide for birds and insects

Culverts

• Allows reptiles, amphibians, and aquatic species to cross roadways 

• Can range in size from as small as 1ft wide to greater than 10ft

• Come in a variety of shapes and materials

Overpasses/Ecoducts

• Allow animals to cross over the roads

• Similar to tunnels but not as wide 

  • Minimum: 130-165ft wide 

• Can also be modified to work for humans and wildlife 

• More used for ungulates/carnivores

Cattle Guards

• Paired with fences to prevent animals from going around (getting on road)

  • Often on on-ramps

• Used for ungulates 

• Sometimes include culverts or modified drainages underneath to allow small animals to get out 

  • Be able to exit underneath the road

Animal Detection Systems

• Sensors used to detect animals and activate signage to alert drivers 

  • Infrared, thermal, motion-activated 

• Usually used for larger animals 

• Human prevention

Implementation

• Not as common in Texas

• Pretty high crash reduction just by preventing animals from being on the road in the first place 

• Cattle guards having the highest crash reduction