Seat belt laws?

http://www.dmv.ca.gov/pubs/vctop/vc/vctoc.htm
This is the California Vehicle Code. the general rules will be in here, in Division 12 - Equipment of Vehicles.
I've been looking at this also to see if there was anything saying "no" to 4 or 5-point harnesses, as the 3 point belts in my Duster are shot. Havn't seen anything that says "no" to 4 or 5-points yet, but will call when I get closer to making a decision.