Road Ecological Workgroup

Wildlife-vehicle collision research program


On Hungarian highways the total number of animal kills rose significantly through 2007 with the increase in kilometres of road, traffic volume and the density of big game. 5% of highway accidents are caused by Wildlife-vehicle collisions (WVCs) and 1-2 accidents lead to the death of the driver. WVCs peaked at 1418 individuals/year in 2007. After 2007 there a slow decline started despite the increase in the total length of roads.

Despite of all efforts, unfortunately many of wild and domestic animals pass through the fences lining the highways. They climb over, jump over,  dig out the bottom or simply bypass and get into the protected area where the fence ends. Where the fence ends, our work begins. Our work group was founded to help solving this very considerable problem, the wildlife–vehicle collision. Our goal is to design, install and test a multi-component system, which can actually reduce the number of WVCs.


Members of the workgroup:

Eötvös Loránd University, Department of Systematic Zoology and Ecology

Univ. of West Hungary, Inst. of Wildlife Management and Vertebrate Zoology

Bükk Mammalogical Society




Our research currently goes on three main scopes:

1) Complex study  of wildlife vehicle collisions (WVCs) on highways.

2) Spatio-temporal investigation of WVCs on railways.

3) Testing and innovating mitigation methods

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Updated: 2013. április 17., 15.46:13 +0200    Contact:




List of the tested devices and methods:

  • Wegu and Swareflex optical reflectors

  • Swareflex acoustic reflector

  • Ultrasonic repellent with IR motion sensors (Weitech, Animalchaser, Digisale)

  • Ultrasonic repellent without motion sensors

  • Acoustic reflector without sensors (INKE1)

  • Acoustic reflector with motion sensors (INKE3)

  • Chemical repellents

  • One-way doors

Main results

1) in general, most WVCs occur at highway intersections, or in interchanges; 2) red fox casualties also occurred at interchanges as well as at wildlife passages; 3) wild boar fatalities were not frequent at interchanges, but were recorded near railways and forests that parallel highways; 4) otter-vehicle collision hot spots were found near their habitats and migration corridors such as lakes and streams, but many otter kills were recorded near passages similar to fox kills and 5) for otter and wild boar we were able to examine the role of local population density; most WVCs happened in areas of high population density.

Most accidents at interchanges occur for one of two reasons: 1) the animal runs outside the fence and enters through the fence at the ramp of an interchange; 2) it enters at a defect in a fence, runs along the inner side of the fence and becomes funnelled onto the ROW. Interruption in the continuity and its linearity are important factors in both cases.

The WVC-dataset is displayed on Google Maps.


The number of WVCs could be reduced significantly if the entry of animals at interchanges could be prevented. Because fences can not be constructed across ramp- and access roads, another solution must be sought. WVCs that occur at interchanges can be divided into two groups in regard to their relation to the interchange: 1) WVCs that occur when animals pass directly into the interchange and are killed on the spot and 2) pass into other locations such as gaps and drainage tunnels but are killed at interchanges. To prevent these two types of WVCs, different methods must be applied.

            For case of type 1 WVCs, acoustic game repellents, already approved for agricultural projects may be a solution. During our study we tested many kinds of game repellents but only one was found effective. At an interchange located in a sparsely populated area, a high-volume, acoustic game repellent, operating with a motion detector, and attached to the end of a fence appeared to solve the problem.



Please watch our video on a field test:


            To reduce the type 2 WVCs the installation of escape ramps and one-way gates may prove helpful. These structures are used in North-America to allow animals trapped within the fencing to return to their habitat.


One-way gate with a roe deer near the highway M1


            Optical reflectors are often installed for mitigative purposes but most studies show that these devices did not significantly reduce the number of WVCs. Several studies investigated the response of ungulates; however, they did not report any behavioral changes on the part of animals that might reduce the number of WVCs.


Swareflex acoustic and optical reflector on highway M1