WISCONSIN (CBS 58) -- The state Department of Transportation is urging drivers to be alert on the roads after 13 separate incidents involving vehicles striking county snowplows this winter.

According to the Wisconsin County Highway Association (WCHA), serious incidents have occurred in Calumet, Marinette, Portage, Shawano, Waukesha and Wood counties, forcing several plows out of service.

Officials say in many cases, the plows were struck from behind. Snowplows travel at slower speeds, and following too closely or attempting to pass a snowplow puts drivers at serious risk.  

“Every time a snowplow is hit, it puts operators at risk and takes critical equipment off the road,” WCHA Executive Director Patrick Vander Sanden said. “These crashes are preventable. Drivers need to slow down, stay back and be patient.”

Drivers are reminded to avoid distractions, leave room to brake, slow down in slick conditions and stay at least 200 feet behind a working snowplow.

“Road and weather conditions can change quickly during Wisconsin winters and snowplow operators brave winter’s worst to keep our roads safe and passable,” WisDOT Secretary Kristina Boardman said. “We all want it to make it safely to our destination, so let’s take it slow on the road and please give space to snowplows.”