RCW 46.61.670: Driving with wheels off roadway.

It shall be unlawful to operate or drive any vehicle or combination of vehicles over or along any pavement or gravel or crushed rock surface on a public highway with one wheel or all of the wheels off the roadway thereof, except as permitted by RCW 46.61.428 or for the purpose of stopping off such roadway, or having stopped thereat, for proceeding back onto the pavement, gravel or crushed rock surface thereof.