Matt Vaughn of the Medical Marijuana Caregivers Association of El Dorado County was pulled over by CHP on June 5, 2005 in Glenn County. Ignoring his status as a patient, the CHP confiscated Vaughn’s pipe and 36 grams of his medicine, and charged him with possession. Despite the fact that his case was dismissed by Glenn County Superior Court on November 9, 2005, the DMV revoked his license, citing his supposed habitual drug use and claiming that he was unable to safely operate a vehicle. On January 27, 2006, ASA filed aWrit of Mandamus in El Dorado Superior Court, appealing the license revocation by the DMV.

On June 1, 2006, the DMV set aside the suspension of Vaughn's driver's license, nullifying the initial suspension and restoring Vaughn's right to drive.