BLACKFOOT — Idaho State Police are investigating two crashes that shut down part of Interstate 15 north of Blackfoot for hours on Tuesday evening.

The initial collision occurred around 5:30 p.m. on the northbound lane of I-15 when one of two backhoes on the bed of a 36-year-old New Plymouth, Idaho, man's 1986 Peterbilt semi-truck struck the Porterville Road bridge, according to authorities. 

Then, one of two backhoes on the bed of a 47-year-old Las Vegas man's 2013 Volvo semi-truck also struck the bridge, authorities said. One of the backhoes fell off the back of a trailer and ended up in the median, according to authorities.

Both drivers of the vehicles were wearing seatbelts, state police said.

The northbound and southbound lanes of I-15 near Blackfoot were closed for hours as crews worked to clear debris from the bridge off of the interstate as well as the damaged semi-trailers and backhoes, authorities said.

The Porterville Road Bridge over Interstate 15 north of Blackfoot remains closed after a backhoe being hauled by a semi struck the bridge from underneath Tuesday evening, causing severe damage to a girder, ITD said in a Wednesday news release.

"The bridge will remain closed until ITD can install a temporary traffic light to allow one lane of traffic over the undamaged portion of the overpass," ITD said. "ITD is still assessing the damage to determine what work will be required to repair the bridge. Motorists are encouraged to check 511.idaho.gov for the latest information on this closure and other traffic events."   

Bingham County law enforcement and emergency medical personnel assisted state police's response to the crash.