Building Roads That Work For Animals And People

It looks like a regular overpass, but it’s not for cars, it’s for bears. Highway designs that allow animals to pass over or under without becoming road kill are getting more and more common, but will they work in the Serengeti, when the road crosses the largest animal migration in the world?


A major road is slated to be built through Serengeti National Park. While it will make travel easier, it could also disrupt the world’s largest annual migration of more than 2 million wildebeest and zebra, as well as the movement of cheetahs, lions, leopards, and elephants and who call the park home. If the road is built, critics, say it will inevitably damage one of the world’s last great animal migrations, while opening up the region to poachers and developers. The Tanzanian government claims it will build a “wildlife-friendly” road that is desperately needed for economic development, a stance backed by famed anthropologist Richard Leakey.

But is it even possible to build a “wildlife friendly” road, let alone one in the Serengeti? Perhaps. As it turns out, the U.S. and Canada have been building them for decades. As many as 1.5 million collisions occur between vehicles and wildlife annually in the U.S. alone. But parts of highways in Washington state (I-90), Montana (I-93) and Canada have redesigned their roads to drastically reduce the incidents and create safe havens for wildlife typically forced to venture across treacherous lanes of traffic.

The most dramatic example is the four-lane highway running through the spectacular Banff National Park in Canada. Fifty miles of new highway, under construction since the 1980s, have been built at a cost of $130 million. Thirty precent was spent on wildlife mitigation such as fencing and wildlife routes. Engineers ensured almost every mile of road has at least one corridor for wildlife to avoid the highway: six overpasses and 40 underpasses crossing the highway, in all.

“It’s dramatically reduced the number of animals hit,” says Trevor Kinley, who manages the wildlife crossing projects for Parks Canada. In the last few years, collisions dropped by more than 80% and at least 200,000 individual wildlife crossings were recorded by coyote, moose, elk, as well as more hesitant animals such as grizzlies and other carnivores which took several years to acclimate.

“These [roads] can be absolutely anywhere,” says Kinley. “It depends on how much you value wildlife in places like Banff or the Serengeti….It’s not a matter of difficult engineering, its a matter of funding.” For Tanzania, which derives 23% of its GDP from tourism, the value on wildlife may be high enough.

In the end, it will likely come down to that. Wildlife friendly underpasses and overpasses (at least in Banff) cost about $1 million to $10 million respectively, and the crucial fences needed to direct animals toward them are not cheap. Opponents of the Serengeti project say the cost will overwhelm public finances and fail to stop the degradation of the park.


“To construct a commercial road through the Serengeti National Park that did not affect its wildlife and ecology would be a monumental undertaking,” wrote David Blanton, director, of the Friends of the Serengeti. “The cost of constructing [it] would be enormous, if indeed [the road] could ever be engineered. For a poor country such as Tanzania, such funds could be put to much better use.”

For Blanton, it’s better to build it somewhere else than try to make a bad road better. “The best road for the Serengeti is the one proposed as the southern, alternative route that goes completely around the park itself,” he wrote. “It has been shown to have clear advantages over the one that bisects the park.”

[Image: Wikipedia]

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About the author

Michael is a science journalist and co-founder of Publet: a platform to build digital publications that work on every device with analytics that drive the bottom line. He writes for FastCompany, The Economist, Foreign Policy and others on science, economics, and the environment.