JENNINGS, La. — Three people were killed and two others seriously hurt in a traffic accident now under investigation by Louisiana state troopers.

A state police news release says the accident happened Wednesday evening on Interstate 10 in south Louisiana’s Jefferson Davis Parish.

A car heading east crossed the median and collided head-on with a westbound heavy duty truck pulling a trailer. What caused the car’s driver to veer across the median is so far not known.

Three people in the car were pronounced dead at the scene by the Jefferson Davis Parish Coroner’s Office. A fourth car passenger and the truck’s driver both were taken to hospitals with serious injuries.

The accident happened shortly after 5 p.m. It led to the shutdown of I-10 westbound for more than two hours Wednesday.