The project is aimed at diverting the 13 cm (5 inch) long amphibians under the pavement during their nocturnal journeys between a mountainside and a lake where they breed.

The population in the area is pegged in the hundreds or low thousands, and mortality rates due to being squashed by cars and trucks have been estimated at 10 percent to 40 percent, said Cyndi Smith, a Parks Canada conservation biologist.

They only make the roughly 800-metre (875-yard) trek at night when it rains, making them nearly impossible to see from behind the wheel.

"It would be one thing if we didn't know this was happening, but we know this mortality is happening. It's right here in front of us," Smith said.

"They're not grizzly bears or big elk or anything like that, but they're still a species that's important to the ecosystem."

It is the latest attempt to help the salamanders on their migration, which occurs a few times each year. They are considered a sensitive species in Alberta.

In the early 1990s, before park staff knocked down a curb the animals were unable to scale, local volunteers lifted about 1,200 of them over the bump through two rainy April nights, according to Parks Canada.

The roadside was then modified a few times with varying results.

Four tunnels, each about 12 metres (39 feet) long, will be spaced along a 600-metre (1,968-foot) stretch of road near the office at Waterton Lakes, which borders Glacier National Park in the United States.

Construction is set to start in October and, when finished, researchers will study how the salamanders adapt to them.