Anyone who has ever driven along a stretch of road outside of a built-up area will have seen the grisly evidence of animals killed by passing traffic. In the U.S., for example, an estimated 1 million vertebrates are run over each day, a rate of approximately one every 11.5 seconds. These collisions cause a threat to both animals (obviously), but also to drivers. Two hundred human deaths take place annuals from vehicle-wildlife collisions, in addition to the numerous injuries caused.
In the Australian state of Tasmania — home to one of the highest roadkill rates in the world — researchers are exploring a new technological solution to this problem. It involves a “virtual fence” system, consisting of alarm units mounted on posts along the side of a three-mile stretch of road. These alarm units, around 80 feet apart, emit sounds and flashing lights to warn animals when a car is approaching. These do not distract drivers because the sound and light are directed to the edge of the road. They are also only loud and bright enough to be noticeable to wildlife in the immediate vicinity.
“The virtual fence technology involves small devices, approximately the size of a mobile phone, mounted on a pole on the side of the road which are triggered by car headlights when they hit a sensor in the device,” Samantha Fox, the researcher who led the project, told Digital Trends. “This sets off blue and yellow flashing lights and a high pitched siren. These together warn local wildlife that a car is coming, and give the animal time to move away from the road.”
Over the course of a three-year trial, the technology has reduced roadkill on one particular road by a massive 50 percent. On this stretch of road alone, this has meant saving the lives of around 200 animals, ranging from wombats to possums.
Fox said that the fences compare favorably to the existing approaches to mitigating roadkill. These approaches have included signs, speed humps, and over and underpasses. All of these have problems, however. People become jaded with signage and start to ignore it. Speed humps, meanwhile, are unpopular with drivers, surprisingly expensive to install, and can come unstuck from the road over time. Over and underpasses fare better, but require considerable construction efforts and only target a certain area. Virtual fences, on the other hand, are cheaper than alternatives, easy to install, and can cover large stretches of road.
A paper describing the project was recently published in the journal Australian Mammalogy.