38601. A person shall not operate, or allow a passenger in, a
recreational off-highway vehicle unless the person and the passenger
are wearing safety helmets meeting the requirements established for
motorcycles and motorized bicycles pursuant to Section 27802.
Straight from Ca. DMV
V C Section 27802 Safety Helmet Regulations
Safety Helmet Regulations
27802. (a) The department may adopt reasonable regulations establishing specifications and standards for safety helmets offered for sale, or sold, for use by drivers and passengers of motorcycles and motorized bicycles as it determines are necessary for the safety of those drivers and passengers. The regulations shall include, but are not limited to, the requirements imposed by Federal Motor Vehicle Safety Standard No. 218 (49 C.F.R. Sec. 571.218) and may include compliance with that federal standard by incorporation of its requirements by reference. Each helmet sold or offered for sale for use by drivers and passengers of motorcycles and motorized bicycles shall be conspicuously labeled in accordance with the federal standard which shall constitute the manufacturer's certification that the helmet conforms to the applicable federal motor vehicle safety standards.
(b) No person shall sell, or offer for sale, for use by a driver or passenger of a motorcycle or motorized bicycle any safety helmet which is not of a type meeting requirements established by the department.
And from the Fedz:
S5.6.1 Each helmet shall be labeled permanently and legibly, in a manner such that the label(s) can be read easily without removing padding or any other permanent part, with the following:
(a) Manufacturer's name or identification.
(b) Precise model designation.
(d) Month and year of manufacture. This may be spelled out (for example, June 1988), or expressed in numerals (for example, 6/88).
(e) The symbol DOT, constituting the manufacturer's certification that the helmet conforms to the applicable Federal motor vehicle safety standards. This symbol shall appear on the outer surface, in a color that contrasts with the background, in letters at least 3/8 inch (1 cm) high, centered laterally with the horizontal centerline of the symbol located a minimum of 1 1/8 inches (2.9 cm) and a maximum of 1 3/8 inches (3.5 cm) from the bottom edge of the posterior portion of the helmet.
(f) Instructions to the purchaser as follows:
(1) 'Shell and liner constructed of (identify type(s) of materials).
(2) 'Helmet can be seriously damaged by some common substances without damage being visible to the user. Apply only the following: (Recommended cleaning agents, paints, adhesives, etc., as appropriate).
(3) 'Make no modifications. Fasten helmet securely. If helmet experiences a severe blow, return it to the manufacturer for inspection, or destory it and replace it.'
(4) Any additional relevant safety information should be applied at the time of purchase by means of an attached tag, brochure, or other suitable means.
So since AB 1595 says a helmet must meet CVC 27802 requirements, and CVC 27802 says a helmet must meet the federal requirements, and the fedz say it must clearly be labled as DOT compliant, I'd say by letter of the law it would need to be DOT compliant.
I assumed it would, but was wondering if it was required to be a full helmet. I looked up right b4 I posted and did not find anything as descriptive as you did Andy, Thanks. Sounds like anything you can wear on a street bike you can wear at the dunes. I've been wearing my MX helmet but the highbacks in my teryx didn't give me a full range of motion with that one, haven't worn one in the new ride yet. Don't need to give em a reason to stop me. Remember when the dunes were so carefree!
You can wear a 1/2, 3/4, or full face as long as it's a DOT compliant. I've fought a couple of helmet tickets riding my Harley, and finally gave in and ditched my peanut shells for DOT 1/2ers. Aint worth the hassle.