Some of this sounds like by Federal law we as Motorcyclists should be able to use any HOV lane.
Exclusive- or Preferential-Use Lanes for High Occupancy Vehicles
21655.5. (a) The Department of Transportation and local authorities, with respect to highways under their respective jurisdictions, may authorize or permit exclusive or preferential use of highway lanes for high-occupancy vehicles. Prior to establishing the lanes, competent engineering estimates shall be made of the effect of the lanes on safety, congestion, and highway capacity.
(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.
20. Why are motorcycles allowed in some HOV lanes?
Motorcycles are permitted by federal law to use HOV lanes, even though they typically carry only one passenger. The explanation for the federal law is that allowing motorcycles to use HOV lanes keeps them moving, and it is considered safer to keep two-wheel vehicles moving than it is to have them traveling in start-and-stop traffic conditions. The individual states can choose to override this provision of federal law, if they determine that there is an inherent safety risk by allowing motorcycles to use HOV lanes. In the State of California, motorcycles are permitted to use HOV facilities unless a traffic control device specifically prohibits them.
http://www.dmv.ca.gov/pubs/hdbk/traffic_lanes.htm
Carpool /HOV Lanes
A carpool lane is a special freeway lane only for motorcycles, buses, and/or carpools. You may use a carpool lane or onramp if your vehicle carries the minimum number of people required for the carpool lane or you drive a low-emission vehicle displaying a special DMVissued decal. Motorcycle riders may use designated carpool lanes, unless otherwise posted.
Signs at the onramp or along the freeway tell you the minimum number of people required for the carpool and the hours the carpool requirement applies. The pavement in this lane is marked with a diamond symbol (?) and the words "Carpool Lane." These lanes are also known as high-occupancy vehicle (HOV) lanes. Do not cross over double parallel solid lines to enter or exit any carpool lane except at designated entry or exit places.
Vehicles towing trailers are typically not allowed to use carpool lanes because they must drive more slowly and are usually restricted to the right-hand lane.
Highway onramp with carpool lane.
