Skip to main content

Idaho Falls to get US-20 free-flowing offramp By: Catie Clark April 14, 2021 0

Looking up the off-ramp from northbound I-15 at exit 119. The free-flowing right-turn lane will be at the top of the ramp.

Looking up the off-ramp from northbound I-15 at exit 119. The free-flowing right-turn lane will be at the top of the ramp. Photo court

Exit 119 on I-15 is possibly the worst interchange in eastern Idaho. It is the interchange that everyone uses to travel between the interstate and the Idaho National Laboratory complex in Idaho Falls. Every tourist heading to Yellowstone National Park also uses the interchange to connect to Highway US-20. The traffic jam every year at the interchange for the Fourth of July fireworks would make a great plot for a horror movie.

The Idaho Transportation Department is currently working on a plan to rebuild the I-15/US-20 interchange but that project is still several years in the future. Until then, ITD is installing a a free-flowing onramp for northbound I-15 traffic heading east on US-20. Construction began the second week of April. Starting on Monday, April 1, no left turns were permitted onto Grandview heading west.

“We want to have the project finished before the Fourth of July,” said ITD spokesperson Megan Stark. “This project is independent of the redesign for the I-15/US-20 interchange; but it should alleviate some of the issues with congestion and traffic back-ups until the new interchange is built.”

“The project will add a free-flowing right-turn lane for traffic heading east on US-20,” Stark added. “It will also add an extra traffic light.” The free-flowing right-turn lane will allow constant traffic movement onto eastbound US-20, mitigating backed-up northbound traffic on the interstate from vehicles leaving I-15 at exit 199. Westbound traffic for Grandview will still stop at the light when the project is complete. The project also does not include any measures to address the evening rush-hour backups on US-20 westbound heading for I-15 south.

ITD will also build and install a pedestrian tunnel and pathway under the roadway at this intersection, replacing the current at-grade cross walk. The tunnel it will provide a safer passage for bicyclists and pedestrians to cross the road.

Westbound traffic for Grandview and US-20 west will be detoured at exit 118 during the course of the project. ITD issued an announcement, cautioning drivers to expect 15 to 20 minute delays for transiting the interchange while construction is in progress.

The cost of the project is approximately $2 million, according to Stark. Cannon Builders of Blackfoot won the bid for the construction. Cannon was also one of the contractors that worked on the rebuilding of the Rose interchange at I-15 exit 98, which was completed last year.

Based on the public feedback from three years of outreach in the Idaho Falls area, ITD has narrowed down the future design of the interchange to three choices, all of which involve the construction of a new interchange north of exit 119. The designs would split traffic for US-20 to Rexburg and Yellowstone from the commuter traffic to the INL and other businesses on the north side of Idaho Falls.

The new interchange project is just beginning the environmental impact and public outreach process required by the National Environmental Policy Act. The engineering design will be crafted in 2025-26 and construction is currently scheduled to begin in 2017. Until then, the new free-flowing right-turn lane should help relieve the back-ups on I-15 from both commuters and Yellowstone tourists heading up US-20.



Back to top