A person who tows and stores a motor vehicle at the request of a law enforcement officer must have a lien on the motor vehicle for the value of the towing and recovery of the vehicle and cargo, storage of the vehicle and cargo, and accident site cleanup, and must have the right to retain possession of the motor vehicle and cargo, subject to the right to retrieve contents under section 168B.07, subdivision 3, until the lien is lawfully discharged. This section does not apply to tows of vehicles parked in violation of snow emergency regulations.