The Idaho Transportation Department says it will grant two permits allowing the oil company ConocoPhilips to move super-size loads of refining equipment along a winding ribbon of two-lane highway in the northern part of the state.
Transport is to commence on Monday of next week, weather permitting.
An array of environmental groups and local residents have fought the shipments for months, arguing, among other things, that the corridor in question adjoins some of the most pristine wilderness remaining in the lower 48 states.
The road, United States Highway 12, is also part of the historic Lewis and Clark National Historic Trail and cuts through Nez Perce tribal territory.
But in a statement, Brian W. Ness, the director of the Idaho Transportation Department, said that the time for deliberation was over.
"I am convinced the record showed the loads can be moved safely, without damage to the roads and bridges and with minimal disruption to traffic and emergency services," Mr. Ness said. "Every argument has been heard and considered. We can no longer delay this process."
The loads, indisputably big and often referred to as "megaloads," can weigh hundreds of thousands of pounds, stand as high as a three-story building and stretch nearly the length of a football field. The shipments would travel only at night and at low speeds, blocking traffic in both directions—although ConocoPhilips and its contracted movers have worked with transportation regulators to build and expand pull-outs along the route to minimize traffic tie-ups and to allow emergency vehicles to pass.
