Thornton interchange construction to begin

The Idaho Transportation Department says construction of the Thornton Interchange overpass on U.S. Highway 20 will begin in March. It should be complete in October.

“It’s a needed project and it completes the construction of interchanges between Idaho Falls and Sugar City,” said Bruce King, the public representative for the Idaho Transportation Department. “This enables us to close the dangerous perpendicular intersections to the state highway.”

The $11.2 million project will elevate the highway to pass over 4700 South and realign the county road north of its current location.

Western Construction Inc., of Boise, will close the Thornton intersection at 4985 South on each side of U.S. 20 and River Bridge Road at the Archer exit, just north of the Snake River.

“It will slow down traffic, and it will be closed down to one lane either direction for part of the construction period,” said King.

Construction crews will also close the median at 3800 South, eliminating left thurns at the intersection. The Burton Road will be permanently closed in October.

Bear World Drive, also known as 4300 West, will remain open through the construction project, but will be permanently closed in October.

The interchange will include north and south entrances and exits.

At the conclusion of the interchange project, all direct accesses to U.S. 20 between Lorenzo and Rexburg will be closed. In addition to 4985 South and River Bridge Road, these accesses include Bear World Drive, field turnoffs, and 3800 South. Motorists thereafter will access areas east and west of U.S. 20 via the new Thornton Interchange (Exit 328).

Including land acquisition, design, construction and landscaping, the total cost of the project will be nearly $20 million.