State Takes Responsibility For I-84 Asphalt Mess Near Boise

A high-tech asphalt that turned Interstate 84 near Meridian into a gooey mess last summer was applied when the temperature was too hot.

That is the conclusion of the Idaho Transportation Department, after an internal investigation of the July 22 incident.

“The state’s taking responsibility,” department spokesman Jeff Stratten said Friday.

The plasticized asphalt was supposed to harden quickly after it was applied on an eight-mile stretch of the westbound right lane. But tires of hundreds of vehicles kicked up gobs of tar and gravel.

Cars were forced to detour into another lane after a semi-tractor trailer tipped over. About 20,000 vehicles a day use I-84 westbound in that stretch, and traffic backed up four miles that day.

Initially, one theory was that the material could have had a chemical reaction with a conventional asphalt applied earlier to even up the surface.

But the investigation determined the asphalt did not cure well at hot temperatures during the midsummer day, Stratten said.

The agency paid for the cleanup of cars that were affected. Stratten said the final cost of the incident has not been determined, since the state still has not settled with the contractor, Kloepfer Inc.