MISSOULA, Mont. -

One man was killed and traffic was backed up for hours on Interstate 90 Monday evening, after a rollover accident west of Missoula near Alberton.

The call came in around 6:30 p.m. for the crash at mile marker 80, a few miles east of Alberton.

Officials tell us a 55-year-old man was driving a 2000 Toyota Camry east on I-90 when he drove off the left side of the road into the median. They say he overcorrected back onto the roadway, then lost control.

The vehicle rolled over through the median and came to a stop in the westbound lanes of I-90.

The driver was ejected, and was pronounced dead at the scene. His identity has not been released.

Montana Highway Patrol troopers at the scene believe speed was a factor. They do not know if alcohol was a factor in the crash.

Vehicles on I-90 were at a standstill for hours as responders worked to investigate and clear the scene.

A trooper told us that traffic was moving again around 9 p.m.