Construction has begun on Thornton Interchange

Construction of the Thornton Interchange (overpass) on U.S. Highway 20 north of Thornton is well underway.

This new interchange will make the U.S. 20 highway between Idaho Falls and Sugar City a full access control divided highway, aiming to improve safety and traffic flow.

Expect delays at 4985 South Thornton, and at River Bridge Road just north of the Snake River.

Crews will also close the median at 3800 South Burton Road, eliminating left hand turn lanes.

Bear World Drive will remain open during construction but will close during October.

Idaho Transportation Department (ITD) said the Thornton Interchange is saving them $350,000.

Eastern Idaho Railroad let Rocky Mountain Power run power along its right of way instead of making the power company reroute the line through Thornton , enabling the project to proceed on schedule and saving ITD significant cost.

In preparation for constructing the Thornton Interchange, ITD planned to pay two-thirds of the $1.3 million cost of rerouting the power line. With the railroad company’s concession, the cost of moving the line was cut to $800,000, of which ITD’s share was $415,000.

The Idaho Transportation Department plans to have the Thornton Interchange project finished by winter, and estimate it will cost $14 million.