Thirty-one people were injured when an overnight bus rear-ended a truck on the Tohoku Expressway early Thursday in the city of Shiroishi, Miyagi Prefecture, local police said.

In all, 38 people — 36 bus passengers and two in the truck — were taken to hospitals, they said. The pair in the truck and 28 on the bus — the driver and passengers, most of whom are in their teens and 20s — sustained minor injuries.

The bus, headed for Sendai from the Tokyo Disney Resort theme park, hit the truck from behind at around 4:10 a.m.

Doctors quoted the driver of the bus, Susumu Tada, 61, a resident of Katori, Chiba Prefecture, as saying he was sleepy at the time of the crash and thus had no clear memory of it. Tada told the doctors he suffered a stroke two months ago and was told by a physician to stop driving.

The operator of the bus, Cruising World, based in Narita, Chiba Prefecture, said of the driver's medical condition, "We have been told he was not in good condition but thought it did not pose any problems with driving."