DRAPER, Utah – The Utah Highway Patrol is investigating why a speeding sedan crashed into a stopped semi on I-15. It’s the third accident involving a car and a semi in the past week and the second fatal.

The accident happened around 11:00 Wednesday when a semi that was having mechanical trouble stopped in the northbound lanes near 14900 South.

UHP Sgt. Justin Dial says they were helping the truck driver when the sedan hit the back of the big rig.

“We don’t know if [the driver] saw the semi or not. It appears it was a high-speed impact so there wasn’t much braking prior to the accident,” Dial says.

The man was pronounced dead on scene.

Earlier that day, a pickup driver was severely injured when he plowed into the back of a slowing semi on southbound I-15 in South Salt Lake.

A woman was also killed when a big rig rear-ended her car on I-80 in Tooele County.