ATVs are not street legal in Oklahoma unless the ATV needs to make a direct crossing with a public road or highway on a trail intended for off-road use. In this instance, the ATV must make a complete stop, yield to oncoming traffic, and cross the street at a 90-degree angle to the road. However, to do this, the driver must have a valid driver's license.
Check out these Okay, OK ATV/OHV resources:
