CA AB2683

Permits installation of one illuminated sign on a vehicle's rooftop, subject to specified safety and operational requirements.

Requires the illuminated sign to be securely mounted, not extend beyond the windshields, and display content only to the vehicle's sides with a maximum light-emitting surface of 720 square inches per side.

Prohibits the sign from displaying flashing lights or interfering with traffic signs and signals, and requires static content when the vehicle operates at 45 miles per hour or more on a freeway.

Does not limit the existing regulatory authority of cities, counties, or city and county governments over vehicle lighting.