A 55-year-old Tok man died Tuesday in a single-vehicle rollover on the Alaska Highway, Alaska State Troopers said.

Michael Verhoff was driving a 2008 Ford F-150 when he crashed at Mile 1357 of the highway, troopers said. The crash occurred about 44 miles from Tok, toward Delta Junction, in the area of the Gerstle River.

A passing motorist reported the accident just after 1 p.m., troopers spokeswoman Megan Peters said. A trooper and Tok emergency medical personnel responded. Verhoff was declared dead at the scene.

There is no clear indication why Verhoff crashed on the straight stretch of highway, Peters said. That could mean he had a medical condition or fell asleep, she said. There was no indication that drugs or alcohol were involved but the state medical examiner will perform a standard toxicology test.

Verhoff wasn't wearing a seatbelt and was thrown from the truck, Peters said.