Road infrastructure is vast covering numerous kilometers worldwide. According to data (2019) from the U.S. Federal Highway Administration, the road network of the U.S. stretches for more than 6,8 million kilometers.
Despite the majority of roadways are concentrated in cities, there are many roads constructed in rural areas that impact the local environment. In many cases, the roadways create an obstacle for animals that cross certain regions. Unfortunately, there have been numerous accidents when some animals tried to traverse the roadways. In the U.S., there are 21 endangered species that are threatened by such road incidents (e.g., Key deer in Florida). What is more concerning is that those accidents increase over time with about 1-2 million animals killed annually.
Fortunately, in recent years, an intelligent technique that protects wildlife and does not impact the road infrastructure has been developed. This method includes the construction of bridge crossings or underground passages from which the animals can safely pass. Those crossings mimic the natural environment and attract the wildlife mitigating the accidents by up to 95%.
In January 2021, Sweden announced the construction of up to 12 bridge crossings across major roadways and railway lines in order to facilitate the transport of reindeer, a deer species that lives near the north pole. Reindeers have been affected by temperature rise and need to travel further in search of food. Therefore, they are many cases of road crossings that could lead to accidents. Until today, local authorities had to close major roads when a herd is moving.
Officials were advised on the location and the design of the bridge crossings by local reindeer herders. One of them stated that it is important for the animals to feel safe when crossing the passage so it must resemble the natural environment. Moreover, fences need to be installed in the facilities so that the reindeers will not jump off.
There are many cases across the world that similar endeavors have been applied. In the Peruvian Amazon, canopy bridges have helped wildlife avoid gas pipelines. In Christmas Island, a species of crabs is enabled to pass over highways via specially designed bridges. In Mexico, jaguars are directed into underground passages constructed below roadways.
Moreover, the largest bridge aiming at animal protection is underway in California. The structure will be established over Highway 101 and will target at restoring the balance of the local ecosystem. This could save mountain lions that constantly decrease in number over the past years probably as a result of isolation. “This ecosystem needs to be reconnected for all wildlife. Segmentation impacts animals both large and small: lizards and birds up to mountain lions," Beth Pratt of the U.S. National Wildlife Federation, stated.