One can’t help but admire the extent and scale of the engineered United States infrastructure. One example is its road network that reaches 4,000,000 miles to support and sustain the transport of goods and people’s lifestyles.
Its road network stretches from coast to coast through its numerous interstate highways from California to North Carolina and New York City; Seattle, Washington to Massachusetts; and Canada to Mexico, forming an extensive and relatively seamless collection of state, federal, tribal, and municipal roads.
Despite being an asset for the people, this enormous infrastructure is becoming a major disturbance to wildlife.
According to a Federal Highway Administration report, one to two million estimated animal and motorist collisions happen each year, costing US$8 billion from human injuries and fatalities.
Apart from its impact on human lives, it is also causing millions of animal deaths as road networks act as barriers for them to access crucial parts of their habitats, which can jeopardize the county’s rich wildlife heritage.
The report “explores the opportunity to renovate this network from one designed to serve the needs of people to one that also proactively accounts for the needs of wildlife, while increasing the safety of both.”
It also examines why long-term transportation plans do not include wildlife protection and needs and the lack of policy that “requires inter-agency integration for mitigating wildlife-vehicle collisions and wildlife connectivity.”
To address the problem, Congress has directed the Secretary of Transport to conduct a study to know the extent of the problem; findings show that there is a “are a growing problem and represent an increasing percentage of the accidents on our roads.”
In 2012, Congress passed an Act – Moving Ahead for Progress in the 21st Century Act (MAP-21), which expressly allowed spending transportation dollars to reduce motorist and wildlife collisions. Congress continued this provision under the most recent transportation act, Fixing America’s Surface Transportation Act (FAST Act 2015), passed in December 2015.
To reduce vehicle and wildlife collisions and the impacts of road networks on wildlife, scientists and transportation practitioners developed a system called wildlife crossing structures or wildlife crossings. A tool to mitigate transportation impact and to “reweave native habitats”.
According to the report, wildlife crossings both over or under the roadways and fencing have reduced wildlife-vehicle collisions by up to 97%.
It also finds that investing in these infrastructures “actually costs society less to solve the problem of collisions than it costs to do nothing.”
Other benefits of the crossings include – connecting habitats that sustain ecosystems, keeping ecosystems intact or undisturbed at a landscape scale and amid widespread infrastructure development, protecting wildlife populations and improving their climate adaptation ability, and promoting societal stewardship of the natural environment public resources.
But despite the crossing’s benefits, its number remains scarce; according to Vox, there are only around 1,000 crossings across the 4 million mile road network in the U.S. The reason for its low numbers is money. But this is about to change with a US$350 budget allocation from Infrastructure Investment and Jobs Act (IIJA).
Wildlife crossings, sometimes called “green bridges,” come in two major types – overpasses and underpasses. They do not come with a standard design. Still, their size depends on what kind of wildlife is using them, ranging from grizzly bears, moose, bobcats to frogs, squirrels, and salamanders, and in some, designed for slow-moving species like turtles, while some targets animals with the highest conservation priority like the Florida panther or the Canada lynx.
Green bridges are usually built with fences to keep wildlife away from the highways while directing them to the crossing. Fences alone could act as barriers that keep them away from crucial habitats.
Because it takes time to train animals to find and use these bridges, regular performance evaluations need to be done in the long term to assess the effectiveness of these green bridges.
Budget constraints require prioritizing expenditures to locations with the highest collision risk and conservation priority. “By prioritizing conservation improvements as early as possible using data-based planning, state transportation agencies can more effectively address state and regional conservation needs in the short and long term,” the report says.
As our thinking on infrastructure provision and management becomes more holistic, we can anticipate more provision of conservation improvements and assets.
These wildlife infrastructure assets, like all assets, will require long term maintenance, planning and ultimately renewal.
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