Thousands of commuters using the Kansas Turnpike found themselves in a major traffic snarl this morning after a semi tractor-trailer overturned shortly before 5 a.m. just east of Lawrence.

The truck’s cab and its two grocery trailers blocked both eastbound lanes and one westbound lane for about two hours — right in the middle of morning rush hour traffic between Lawrence and Kansas City.

One of the eastbound lanes finally reopened to traffic by 7 a.m., according to the Kansas Turnpike Authority.

The truck driver, Dana Gronau, 40, Edwardsville, was taken to Lawrence Memorial Hospital to have cuts to his head and neck treated, according to the KTA.

The accident site was at mile marker 207, which is about three miles east of the East Lawrence turnpike entrance.

Authorities said Gronau apparently fell asleep at the wheel shortly before 5 a.m., then overcorrected. The truck then careened into the barrier that divides the highway, pushing blocks into oncoming traffic.

For about two hours, the overturned truck had blocked both eastbound lanes and also one of the westbound lanes on the highway. Authorities had to clean up spilled diesel fuel.

Before 7 a.m., traffic coming from the west was diverted off of the turnpike at the East Lawrence entrance until at least one of the eastbound lanes was cleared.