A "commercial motor vehicle" is a motor vehicle that:
Federal rules provide that property-carrying drivers of commercial motor vehicles have 14 hours to drive a maximum of 11 hours after coming on duty, after which point federal law requires that they take 10 consecutive hours off duty. Drivers must take a 30-minute break when they have driven for a period of eight cumulative hours without at least a 30-minute interruption. Drivers are allowed to extend the 11-hour maximum driving limit and 14-hour driving window by up to two hours when they encounter adverse driving conditions.
Commercial vehicles may park up to an hour beyond federally mandated rest periods at highway rest areas in Washington.
Commercial motor vehicles that are used in commerce solely to transport property are authorized to park in areas designated by the Washington State Department of Transportation (WSDOT) as chain-up and chain-off areas along highways between May 1 and November 1 for up to an hour beyond federally mandated rest periods when signage posted by the WSDOT authorizes their parking.
The WSDOT is required to post and maintain signage authorizing commercial motor vehicle parking in chain-up and chain-off areas that it determines have sufficient space to accommodate commercial motor vehicles parking for an extended period of time.