In 1998 it was estimated that one million vertebrates were killed daily on U.S. roads, many of them amphibians such as frogs, toads, and salamanders. With traffic volumes rising since then, the global scale of road-kill is severe, with further deaths at unfenced construction sites and railways. For salamanders, most fatalities occur during seasonal migrations between breeding pools and terrestrial habitats.

Because salamanders and newts return to the same pools each spring, they often have to cross roads and are highly vulnerable to traffic. Studies have documented tens of thousands of deaths on short road sections, and some populations face local extinction within decades. Construction sites pose similar threats, highlighting the need for effective exclusion fencing.

Transport engineers have a responsibility to limit these impacts. Properly designed fencing, combined with tunnels and other measures, can greatly reduce mortality at key migration points without disrupting natural life cycles. Fencing can also assist with population assessments before new development begins.