Frieman contests carpool violation, corporate personhood...

CA Vehicle Code section 470: '"Person" includes a natural person, firm, copartnership, association, limited liability company, or corporation.' -- http://www.dmv.ca.gov/pubs/vctop/d01/vc470.htm

CA Vehicle Code section 21655.5 (b): ' The Department of Transportation and local authorities, with respect to highways under their respective jurisdictions, shall place and maintain, or cause to be placed and maintained, signs and other official traffic control devices to designate the exclusive or preferential lanes, to advise motorists of the applicable vehicle occupancy levels, and, except where ramp metering and bypass lanes are regulated with the activation of traffic signals, to advise motorists of the hours of high-occupancy vehicle usage. No person shall drive a vehicle upon those lanes except in conformity with the instructions imparted by the official traffic control devices. A motorcycle, a mass transit vehicle, or a paratransit vehicle that is clearly and identifiably marked on all sides of the vehicle with the name of the paratransit provider may be operated upon those exclusive or preferential use lanes unless specifically prohibited by a traffic control device.' -- http://www.dmv.ca.gov/pubs/vctop/d11/vc21655_5.htm

So that references whatever is on the sign (in case of three or more occupancy required), I couldn't find an image of the signs around here, and this isn't a super official site, but it says the signs say "Two or more persons per vehicle, motorcycles and ILEVs permitted" -- http://rideshare.511.org/511maps/hov_lanes.aspx

But Section 21655.5 (f) 'It is the intent of the Legislature, in amending this section, to stimulate and encourage the development of ways and means of relieving traffic congestion on California highways and, at the same time, to encourage individual citizens to pool their vehicular resources and thereby conserve fuel and lessen emission of air pollutants.'

So, without the intent clause; I think it's reasonable to interpret "Two or more persons" to include corporations, but as it does not impact traffic congestion, I don't see how it fits into the intent clause, so I think there is considerable freedom for a Judge to consider the intent of the legislature and deny this interpretation.

I agree that the most likely consequence is to alter this section of the vehicle code to expressly consider natural persons only.

Yes, showing that the corporation is in the vehicle would also be difficult, and I do doubt that location of the incorporation papers constitute the location of the corporation.