MINERAL POINT, Wis. -

Icy road conditions caused two back-to-back accidents on Highway 151 Friday night, authorities said. No one was injured in the collisions, which happened 3 minutes apart south of Mineral Point, Wis. 

The first accident involving four vehicles happened at Highway 151 and Pittz-Schaaf Road at 4:47 p.m., according to the Iowa County Sheriff's Department and the Wisconsin State Patrol.

Officials said two cars were stopped on the edge of the road on the southbound side because the roads were dangerous. A pickup truck pulling a trailer hit the stopped cars. 

A fourth vehicle, a semi, then sideswiped the stopped truck, the report said. 

The slick roads caused another semi to crash in the same area at 4:50 p.m., State Patrol said. The semi stopped on Highway 151 to wait for trucks to salt the roadway. The semi slid,  picking up speed. 

According to the report, the driver released the brake to avoid a jackknife, but the semi collided with the bridge just south of Pittz-Schaaf Road and jackknifed anyway. The semi was in both lanes and traffic was blocked for 8 hours, State Patrol said. 

Multiple Iowa County public safety agencies responded to the crashes.