Wisconsin Gov. Jim Doyle is calling for an investigation of how well state emergency crews responded to a massive traffic backup on Interstate 90 on Wednesday, Feb. 6.

According to the Wisconsin State Patrol, the traffic jam involved more than 2,000 vehicles on a 17-mile stretch south of Madison. The area had just received 20 inches of snow.

The state patrol also reported that 1,256 of the vehicles involved were tractor-trailers.

The traffic jam stranded hundreds of people, who were forced to spend the night on the highway, waiting up to 12 hours for help.

The head of the state patrol is defending its response, noting that there were no deaths or serious injuries.

Critics say the massive traffic jam had been building up for three hours before the patrol responded in force.