STRATFORD, Conn. (AP) — A driver going the wrong way on Connecticut’s Merritt Parkway crashed head-on into a minivan early Thursday, killing all four people in the vehicles and closing one side of the highway for nearly seven hours, state police said.

State police said an SUV was traveling northbound in the southbound lanes when it crashed into the minivan and burst into flames at about 1:45 a.m. in Stratford.

Television news video of the aftermath showed a minivan with its front end smashed in and a heavily damaged sport-utility vehicle lying on its side on the highway, also known as Route 15.

Concern is increasing in Connecticut about wrong-way highway crashes, nearly all of which are caused by drunken drivers, officials say. The state Department of Transportation has identified 200 off-ramps as “high risk,” in part because of multiple ramps that meet at the same location.

State police said all three people in the minivan were killed — men ages 65 and 80 and an 81-year-old woman, all from Easton, Connecticut. The SUV is registered to a Massachusetts resident and the medical examiner’s office was working to identify the driver, who also died, authorities said.

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There was a second accident as well: A state trooper responding to the scene collided with a vehicle that was stopped in the roadway with its lights off, as its driver tried to help people in the head-on crash. The trooper had minor injuries, state police said.

The state Department of Transportation reported 13 wrong-way crashes that killed 23 people in 2022. Preliminary data for 2023 shows five wrong-way accidents killed seven people, the DOT said. And this February, four people were killed in a wrong-way crash on Interstate 95 in West Haven.

State crews have been installing alert systems on highway ramps that flash bright red lights to drivers going the wrong way. Systems in some locations also alert state police and transportation officials.