Slamming a vehicle into an elk or deer is more harmful for humans than many realize. These creatures cause approximately 1.5 million collisions each year, resulting in around 150 deaths, according to the Insurance Institute for Highway Safety. Another 10,000 people suffer injuries from collisions with the animals.
Animal-car collisions can also cost governments money. For instance, the Arizona Department of Transportation (ADOT) has a financial stake in this problem because the state "owns" all wildlife, meaning the government is financially liable when an elk or deer obstructs a car or truck. The state paid more than $3 million for one such lawsuit in 2003.
For the past seven years, Arizona has been moving to solve the problem using a GIS tool that determines where deer and elk cross highways so underpasses can be built for the animals. Arizona's Game and Fish Department (AGFD) implemented the project in 2002 in partnership with ADOT, which funded most of the project.
Statistics suggest the program is effective. Deer and elk collisions dropped from 56 to eight on one major Arizona highway in one year after strategically placed underpasses were built, according to Jeff Gagnon, research technician for the AGFD. Another highway averaged 12 deer or elk accidents a year before it was targeted by the project; that highway has only seen one animal collision in the past two years, Gagnon said. The state hasn't yet measured what the project has done to the percentage of vehicle collisions statewide.
Gagnon said GIS helps his agency persuade ADOT to invest in the underpasses, which cost more than $1 million each. "They really buy into it when you pull out a map and say, 'This is where these animals are crossing,'" Gagnon said.
In 2004, ADOT and the AGFD organized the Arizona Wildlife Linkages Workgroup. This group expanded the project to include nine organizations with relevant input, such as the U.S. Department of Interior's Bureau of Land Management, the Federal Highway Administration, the U.S. Fish and Wildlife Service, Northern Arizona University, the Sky Island Alliance and other private environmental organizations. After pooling its resources, this team created a more developed GIS tool that's becoming a model for other states interested in solving animal-car collisions.
Animals Do the Legwork
Before Arizona could do a GIS analysis of where to install underpasses, officials needed data from the animals. Gagnon and others collared elk and deer with GPS devices. The resulting data showed animals crossing highways at areas where pastures or water waited on the other side. ADOT began installing underpasses. Conveniently some of them already existed for other purposes, like transporting water. GIS maps gave guidance to the state on how far to extend the fencing necessary for funneling the animals into the underpasses.
"We've had video cameras on some of those underpasses for about six years now. We've documented [more than] 6,000 animals using them. Most of those are elk, some deer -- 11 different species," Gagnon said. He added that even longhorn sheep and desert tortoises use the underpasses.
GIS technicians and fieldworkers attempting this in other states should expect to stay connected to the project throughout its life cycle, according to Susan Boe, GIS spatial analyst for the AGFD. With each highway the state converted for animal passage, she ran GIS tests of animal movements before, during and after construction. To run the analysis, Boe used ESRI's ArcGIS 9.2 software. To complete the job, she downloaded free software called Animal Movement, which is an extension of ESRI's ArcView application.
"Using Animal Movement, I was able to connect the dots to follow the path of movement," Boe explained. "It was what I used to find out where the animals were crossing the highway."