What Is a Non-Highway Vehicle in Illinois? Canva Canva loading...Get our free mobile appIllinois defines a “non-highway vehicle” as one not designed for public roads. Under Illinois law, local governments can allow non-highway vehicles on certain roads, but only where the posted speed limit is 35 mph or less. Your non-highway vehicle needs brakes that actually stop you, a working steering setup, real tires, and a rearview mirror. Visit ilga.gov to read the Illinois Vehicle Code.