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:

  • i) an opening in the fence, constructed to guide animals over the road,
  • ii) an electronic system for detection of animals near to the road, and
  • iii) a system for alerting drivers of the presence of animals and to reduce vehicle speed.

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 road sides, and effect on wildlife accidents and drivers behaviour. 

Field methods should include studies of animal movements and behaviour near and through the crossing (for example by photo traps and snow tracking), and the effect of driver alert systems on vehicle speed and drivers vigilance. The effect on wildlife accidents will be studied with a BACI approach on a larger geographical scale. Also the technical functionality of the detection and warning systems will be assessed. As far as possible, data should be gathered from (and in cooperation with) monitoring studies conducted within the respective investment project. Effect sizes will be compared with the investment costs.

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


This subproject produces values of 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 most important outcome is that the results enables cost-efficiency comparisons between level crossings and over-/underpasses. 

Study objects/sites

Few level crossings will be available for study, and accordingly all these are candidates for study objects.

  • At highway E22 Haraldsmåla 
  • Two crossings alongs county road 108 north of Svedala (Bökeberg + Sjödiken)
  • At highway E22 south of Brömsebro (early planning, unclear)
  • At national road 27 Tranemo-Borås 
  • At national road 42 Koberg

Other proposed sites for level crossings warning systemscan be selected for research, depending on where such are constructed.

Photo: ?