Michigan State Police are investigating a six-vehicle accident that shut down southbound I-196 at Coloma Road for about an hour on Sunday. Troopers say a truck pulling a large trailer with a bulldozer jack-knifed and blocked the southbound lanes. Six separate collisions resulted. Nobody was hurt, and the highway opened back up shortly after 4 p.m. according to the Michigan Department of Transportation. Troopers say the crashes are a reminder to slow down and adjust your speed based on the weather and road conditions.