Beware of Road Side Emergency Vehicles.  All States have some type of move over law to protect any and all types of emergency assist vehicles a long the highway.  It just so happens that both Illinois and Missouri law reads the same.  "State law requires drivers approaching a stationary emergency vehicle displaying flashing lights, including towing and recovery vehicles, traveling in the same direction, to vacate the lane closest if safe and possible to do so, or slow to a speed safe for road conditions."  Be safe out there.