Junction at Bear World to permanently close Monday

Press release from Idaho Transportation Department:

The 4300 West (Bear World Drive) junction with southbound U.S. 20 will close permanently Monday (Oct. 24). The junction is the last of 18 dangerous, at-grade (level) intersections to be eliminated along the 34-mile stretch of U.S. 20 between Idaho Falls and Sugar City.

The new Thornton Interchange will allow motorists to enter and exit the Bear World wildlife park via a two-mile route along county roads (3300 West, 5200 South and 4300 West) starting in late November. Until then, drivers can access the park via county roads available from the south Rexburg Interchange (Exit 332).

Eliminating junctions that let motorists enter and exit freeways at right angles to the busy thoroughfares, and then cross several lanes of traffic, greatly improves highway safety. Since the Idaho Transportation Department began closing these junctions and building interchanges in 2000, severe-injury crashes have steadily declined, from 80 prior to the change to only 20 along the stretch last year, and fatalities have dropped from four to less than one per year.

Since 2000, the transportation department has built seven interchanges along U.S. 20 between Idaho Falls and Sugar City. They include the Sugar City-Salem (Exit 338), Driggs-Jackson (Exit 339) and County Line (Exit 318) interchanges built in 2001, the St. Leon (Exit 311) and Hitt (Exit 313) interchanges built in 2004-2005, the Menan-Lorenzo (Exit 325) interchange built in 2010-2011, and the Thornton Interchange (Exit 328) being built this year.

Crews permanently closed 4985 South (Thornton intersection) on each side of U.S. 20 and the River Bridge Road (Archer exit) just north of the Snake River this spring in connection with commencing construction of the new Thornton Interchange. With construction nearing completion, workers closed the 3800 South (Burton Road) junction with southbound U.S. 20 on Monday (Oct. 17).

Overpasses of the new Thornton Interchange will open as early as next week. Workers then will realign 4700 South under these overpasses and connect on- and off-ramps of the interchange to the county road. The transportation department expects the interchange to be fully operational by Thanksgiving.

The new Thornton Interchange not only will improve traffic safety and flow along U.S. 20, but also will connect Madison County’s planned 5000 South project, which is designed to improve traffic movement in the southern part of the county.

Total cost of the full interchange project, including land acquisition, design, construction, junction closures and landscaping, will be nearly $20 million. Final landscaping of the interchange will be finished in the spring.