Kerbstones / Curbstones

Kerbstones or curbstones direct amphibians to storm drains or keep them on the road for an unnecessarily long time. The remedy is to bevel the curbs. The number of amphibians in storm drains or dead amphibians on the road can be reduced many times over. If the amphibians remain on the road too long, they can also dry up, depending on the weather; smaller subadult amphibians in particular dry up quickly. The mostly walking toads are severely affected by the kerb stones (compare Figures 1-3). Also strongly affected are the walking caudates.

Figure 1: This kerbstone keeps the common toads and other amphibians on this cantonal road or leads them to the storm drain.
Figure 2: Numerous common toads linger on the drain elbow, the main culprit here is the kerbstone.
Figure 3

Dropped kerbstones / flat kerbstones

Dropped kerbstones allow amphibians to exit the road (compare Figure 4). However, too much flattened kerbstones no longer drain the rainwater nicely. It is better to install flat kerbstones directly than to subsequently drop the kerbstones. With the right choice of flat kerbstones, the rainwater can still be drained well.

Figure 4: Dropped kerbstones

Asphalt ramps / Kerbstone ramps

A less expensive option than dropping the kerbstones is to install asphalt ramps (compare Figures 5 and 6).

Figure 5: Asphalt ramp around the storm drain
© Grün Stadt Zürich / Stefan Hose
Figure 6: Alpine newt uses the asphalt ramp.
© Grün Stadt Zürich / Anna Struth

Wildlife Kerbstone

The Wildlife Kerbstone effectively reduces the number of amphibians caught in the storm drain (compare Figures 7 and 8). This system can make sense in certain places, for example where the kerbstones cannot be dropped.

Figure 7: Wildlife Kerbstone
Figure 8: Wildlife Kerbstone


Amphibians are still rarely considered in kerbstone design and selection. It is time to change this.