Cal. Veh. Code § 9400.8

Notwithstanding any other provision of law, if the voters approve Senate Constitutional Amendment 1 of the 1989–90 Regular Session, no local agency may impose a tax, permit fee, or other charge for the privilege of using its streets or highways, other than a permit fee for extra legal loads, after December 31, 1990, unless the local agency had imposed the fee prior to June 1, 1989.