I-84 will be widened between Franklin Boulevard and Karcher Road in Nampa

Construction to widen Interstate 84 in Nampa to three lanes between Franklin Boulevard and Karcher Road should start sometime in October after an Aug. 29 confirmation of a $90.2 million federal grant.

This $150 million projects widens another 2.8 miles in a 10-year campaign that has widened 18.7 miles of I-84 between Gowen Road in eastern Boise and Franklin Boulevard.

Community Planning Association of Southwest Idaho (COMPASS) rates widening the Franklin-Karcher stretch as the region’s No. 1 transportation priority.

The existing two-lane configuration in each direction will actually have four lanes. Idaho Transportation Department is also adding an auxiliary lane that starts at Franklin/Karcher and ends at Karcher/Franklin to enable drivers to go from interchange to interchange without having to merge into the main travel lane, ITD spokesman Jake Melder said.

ITD competed for the $90.2 million grant from the $1.5 billion Infrastructure For Rebuilding America (INFRA) program established by President Donald Trump.

Completion is estimated for 2012, Melder said.

The project also includes building a new Karcher Road overpass, which will require an eight-to-10-month closure of that crossing.

Temporary lanes will be paved on existing shoulders to maintain two lanes in each direction during peak hours. These temporary lanes will be the first phase of work starting in the October timeframe, Melder said, with lane work starting in summer 2019.

The new lanes will be added in the center median in two phases. The first phase will address both directions between Franklin and Northside Boulevard.

COMPASS, ITD, the city of Caldwell and Canyon County each added $125,000 in matching funds with state funding cover the remaining costs from Transportation Expansion and Congestion Mitigation, the general fund surplus, and a portion of the cigarette tax dedicated to transportation, according to an ITD news release.