Well, a "driver" does not have to be moving the vehicle to qualify as a driver. You only have to be in control of the vehicle ...
305. A "driver" is a person who drives or is in actual physical
control of a vehicle. The term "driver" does not include the
tillerman or other person who, in an auxiliary capacity, assists the
driver in the steering or operation of any articulated firefighting
apparatus.
So, by extension, I would assume an argument can be made that the vehicle does not have to be in motion.
But, there is case law associated with DUIs that might be applicable here.
From CPOLS:
To constitute "driving," there must be some actual movement. (Mercer (1991) 53 Cal.3d 753, 768.) However, only slight movement of the vehicle is necessary, i.e., just a few feet, or even inches. (Padilla (1986) 184 Cal.App.3d 1022; Henslee (1985) 168 Cal.App.3d 445.) For a motorized vehicle, it includes any movement with the motor off, such as coasting down a hill, or pedaling a moped. (Jordan (1977) 75 Cal.App.3d Supp. 1.)
So, it might go either way.
If you want to spend more money than the fine, you can consult an attorney and have them make the arguments for you. If you want to give it a go yourself, you can try. Or, you can take Prop. 36 (drug treatment) and learn to quit using pot and stay out of future trouble for dope.