Level crossings and wildlife warning systems


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Level crossings (in Swedish VGU terminology: “viltövergångsställen”) may provide a cost-efficient alternative to under- and overpasses, even if only for larger species and under certain conditions.

The idea with such passages is that the animals should be directed to certain shorter sections of a road, where the drivers are alerted for animals on or near the road.

Level crossings combine three main components:


An opening in the fence, constructed to guide animals over the road.

An electronic system for detection of animals near to the road.


A system for alerting drivers of the presence of animals and to reduce vehicle speed.

Road sign for wildlife level crossing. Photo: J-O Helldin.

Still not many level crossings are built, and results from available studies are contradictory. So uncertainties remain whether this type of wildlife passage can be made functional at all, and if so to what degree the functionality depend on technical details of the different components.

Despite the uncertainties, for economic reasons there is a big interest in constructing level crossings, and if made functional they can be used on many roads with intermediate traffic flow.

Therefore, it is crucial that the performance of new level crossings is monitored and that the results are properly analysed and published. The performance of level crossings depend on both animal and human behaviour, and must be measured in terms of both wildlife connectivity and traffic safety.


In this subproject we will monitor the performance of level crossings in terms of wildlife use and connectivity between roadsides, and effect on wildlife accidents and driver behaviour.

Field methods include studies of animal movements and behaviour near and through the crossing (photo traps, potentially also snow tracking), and the effect of driver alert systems on vehicle speed.

The possibility to analyse the effect on wildlife accidents will be dependent on the number of study sites. The technical functionality of the detection and warning systems will be evaluated by the Transport Administration in a separate project. Data are retrieved from monitoring studies conducted within the respective investment project. The economic outcome based on the reduction in wildlife accidents may be compared with the investment costs at study site road 108 Sjödiken and road 42 Koberg.

The results will be summarized in a report for practitioners, where the international knowledge level regarding efficiency of level crossings will be described and best recommendations for construction will be given. In addition, the results may be published scientifically.



This subproject gives insights in the efficacy of level crossings in connecting wildlife between roadsides and in decreasing the number of wildlife accident. Efficacy is separated between species and categories of animals (age and gender) to put light on population level impacts.

The results will contribute to cost-efficiency comparisons between level crossings and over-/underpasses. 

Study objects/sites

Three level crossings will be available for study during 2019-2022:

Sjödiken, road 108, north of Svedala

Detection and warning system from november 2019.

Koberg, at national road 42

Opened for animals from december 2019, but no detection or warning system until fall 2020?

Haraldsmåla, at motorway E22

Existing detection and warning system.

Other proposed sites for level crossings:

    Additional site at road 108 north of Svedala

    At national road 27, Tranemo-Borås

    Publications and outreach

    The subproject Level crossings and wildlife warning systems has resulted in:

    Contact for the subproject

    Mattias Olsson

    +46 (0) 739-47 11 47