Published 9th April 2025

In this latest blog ARC’s Conservation Director, Jim Foster, discusses possible solutions relating to the complex issues of amphibians  and roads

In the conservation world, it’s often the simple solutions that gain the most attention. One such example is the use of amphibian ladders in roadside drains, technically known as gullypots. These ladders can indeed help animals escape from these deadly traps, but they are far from a complete solution. Roads pose wider problems than just gullypots. Without addressing the wider issue of road layout and kerbs, we risk treating the symptom rather than the cause.

Amphibian ladders

Amphibian ladders help animals exit gullypots and can be useful in certain situations. For example, where there are particular gullypots that regularly catch many animals and there is an easy route off the carriageway very close by. But they are rarely a durable or holistic fix if installed without any other measures. They can create an impression that the problem has been fully resolved when, in reality, amphibians are still at risk. Even with ladders in place, amphibians can become temporarily trapped in gullypots, delaying their journey and increasing their exposure to traffic. Additionally, the ladders can cause problems for maintenance, and may be damaged by routine cleaning. Largely because of this, some councils will not allow their installation. ARC is concerned that ladders are now frequently installed on new developments, where it is actually preferable to design a drainage system that avoids gullypots, at least in high risk locations.

It is feasible that ladder design improvements in future will help resolve these problems, though even then we would like developers and councils to take a wider view of the issues facing amphibians on roads.

An overlooked problem: upright kerbs

One of the most significant yet frequently ignored factors contributing to amphibian road mortality is the use of upright kerbs. These act as barriers that prevent amphibians from leaving the road, leaving them stranded in the path of oncoming traffic, as well as guiding them into gullypots. Despite their importance, modifications to kerb design are rarely implemented in the UK, whereas other countries have been more proactive in addressing the issue.

Arguably, a more effective approach than focusing on ladders would be for councils to modify kerbs, incorporating “dropped” kerbs wherever possible, to allow amphibians to exit the road easily. Wherever possible, the removal of kerbs and gullypots should also be considered, replacing them with a Sustainable Drainage System (SuDS) approach. But if that is not feasible then it’s often best to maximise the length of dropped kerbing close to gullypots.

Thinking more holistically

While change is slow, there are examples of good practice emerging across the UK. I have been collecting case studies to develop practical guidance for developers, councils and amphibian workers. This includes sites where dropped kerbs have been installed as a “retrofit” measure to address an existing problem, as well as locations where new road designs have incorporated modified kerbs and drainage designs. Whilst it’s best for new roads to avoid amphibian hotspots, where this isn’t feasible then some measures can help with making the road edges more permeable, and avoiding the use of gullypots.

Moving forward

Our focus should be on promoting these effective, durable, low-cost solutions to councils and developers. We need a shift in thinking—one that moves beyond ladders as a notional quick fix and towards more systemic change in road infrastructure. By making simple modifications to kerbs and reassessing the use of gullypots, we can significantly reduce amphibian mortality and create safer passage for these species.

As ARC continues to document best practices and engage with decision-makers, I remain hopeful that councils will take the necessary steps to integrate amphibian-friendly designs into their road networks. The solutions are within reach—we just need to build them into routine practice.

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Banner image: Amphibians like this common toad find it difficult to climb vertical kerbs. Photo: Jim Foster/ARC 

Images from top to bottom:

A smooth newt using a ladder to escape from a gullypot. Photo: Jim Foster/ARC

Dropped kerbs allow newts, frogs and toads to leave the carriageway more easily than climbing vertical kerbs. Photo: Jim Foster/AR

Sustainable Drainage Systems allow developments to exclude gullypots and high vertical kerbs, hence designing out the key risks for amphibians. Photo: Jim Foster/ARC