[Napa Skip]

I suppose I could have been more succinct had I posted this summary from the California Highway Patrol:

California [Seatbelt] Law:

1. Children under the age of 8 must be secured in a car seat or booster seat in the back seat. 



2. Children under the age of 8 who are 4' 9" or taller may be secured by a safety belt in the back seat.

3. Children who are 8 years and over shall be properly secured in an appropriate child passenger restraint system or safety belt.

4. Passengers who are 16 years of age and over are subject to California's Mandatory Seat Belt law. 



Where a rumble seat fits in with regard to a "back seat" I do not know.