From the
California Vehicle Code:
CVC Section 21655 States:
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 or a mass transit vehicle may be operated upon those
exclusive or preferential use lanes unless specifically prohibited by
a traffic control device.
(c) When responding to an existing emergency or breakdown in which
a mass transit vehicle is blocking an exclusive or preferential use
lane, a clearly marked mass transit vehicle, mass transit supervisor'
s vehicle, or mass transit maintenance vehicle that is responding to
the emergency or breakdown may be operated in the segment of the
exclusive or preferential use lane being blocked by the mass transit
vehicle, regardless of the number of persons in the vehicle
responding to the emergency or breakdown, if both vehicles are owned
or operated by the same agency, and that agency provides public mass
transit services.
(d) For purposes of this section, a "mass transit vehicle" means a
transit bus regularly used to transport paying passengers in mass
transit service.
(e) 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.
(f) The provisions of this section regarding mass transit vehicles
shall only apply if the Director of Transportation determines that
the application will not subject the state to a reduction in the
amount of federal aid for highways.