Larry Hirsch, 50, died when the red minivan he was driving on Pennsylvania Road collided with a pickup truck hauling concrete.
Brownstown Township police are not releasing any information about the crash. Reports suggest the pickup truck may have crossed the median and struck the minivan but there has been no confirmation from police.
"When I saw it, I just knew something horrible happened," says witness Bruce Donaldson. "I was up on the roof working and me and my fiancee heard a big bang.
"I have no idea exactly what happened. I just know it was horrific."
Hirsch's two youngest children were inside the vehicle during the accident.
Family members say 2-year-old Haylee Hirsch and 4-month-old Felicity Hirsch were taken to C.S. Mott Children's Hospital in Ann Arbor.
As crews cleaned up remnants of the accident, Brownstown police continue to investigate how it happened.
It is unclear what caused the crash, but one thing is apparent.
"It's so terrible, it's a tragedy," Donaldson said.