A semitrailer approaching a construction area on the Indiana Toll Road (search) rear-ended a car, triggering a chain-reaction of crashes. Four people were killed and seven were injured.

The accidents happened about 4:45 p.m. Sunday near Bristol, 25 miles east of South Bend (search). In all, five cars and the semi were involved.

The eastbound semi struck the first car about a half-mile before the construction area, as a flashing sign directed drivers to merge from two lanes to one, Indiana State Police said.

Three of the dead were riding in the same vehicle, police said.

The eastbound lanes of the toll road near Bristol were closed for about five hours, police said.

"It looks like the semi wasn't able to slow down in time and caused the accident," Indiana State Police trooper Jeff Dolson (search) said.

Police had not released the names of those killed or injured as of late Sunday.