The barrier effect of roads for small animals is partly an effect of the width of the tarmacked surface. The number of vehicles and their speed, however, also affect the number of animals killed. Different types of measures can be beneficial for wildlife:

Reducing the width of the infrastructure

• Agricultural and forestry roads which are not tarmacked are more easily crossed by small animals, e.g. invertebrates.
• On agricultural roads an alternative to a fully tarmacked road is the provision of two concrete tractor-strips. The area between the strips is kept vegetated, thus providing cover for invertebrates

Reducing the amount of traffic

• Temporary closure of roads is a suitable measure in cases where animals only cross a road during a limited period. It is recommended, for example, to protect amphibians on their migration to spawning grounds (closure during humid nights in spring) or to allow wild reindeer to move to their wintering grounds undisturbed (closure of a road during critical periods in winter).
• Any other common measure to reduce the amount of traffic (one-way streets, restricted access, etc.) can also be used as a measure to reduce collisions with wildlife.

Reducing the speed of the vehicles

• Reducing the width of the road can reduce the speed of the vehicles and thus reduce the risk of collisions with mammals. This measure is suitable for rural roads with relatively light traffic.
• Temporarily or permanently lowered speed limits at high-risk spots can contribute to reducing the risk of collisions with mammals.
• Where collisions happen mainly during the night, speed limits at night might be sufficient.
• Speed ramps are recommended on roads with light traffic.