22400.  (a) No person shall drive upon a highway at such a slow
speed as to impede or block the normal and reasonable movement of
traffic unless the reduced speed is necessary for safe operation,
because of a grade, or in compliance with law.
   No person shall bring a vehicle to a complete stop upon a highway
so as to impede or block the normal and reasonable movement of
traffic unless the stop is necessary for safe operation or in
compliance with law.
   (b) Whenever the Department of Transportation determines on the
basis of an engineering and traffic survey that slow speeds on any
part of a state highway consistently impede the normal and reasonable
movement of traffic, the department may determine and declare a
minimum speed limit below which no person shall drive a vehicle,
except when necessary for safe operation or in compliance with law,
when appropriate signs giving notice thereof are erected along the
part of the highway for which a minimum speed limit is established.
   Subdivision (b) of this section shall apply only to vehicles
subject to registration.



22401.  Local authorities in timing traffic signals may so regulate
the timing thereof as to permit the movement of traffic in an orderly
and safe manner at speeds slightly at variance from the speed
otherwise applicable under this code.


22402.  The Department of Transportation may, in the manner provided
in Section 22404 determine the maximum speed, not less than five
miles per hour, which can be maintained with safety to any bridge,
elevated structure, tube, or tunnel on a state highway.  Said
department may also make a determination with reference to any other
highway upon receiving a request therefor from the board of
supervisors or road commissioner of the county, the governing body of
the local authority having jurisdiction over the bridge, elevated
structure, tube, or tunnel.


22403.  Any local authority may, in the manner provided in Section
22404, determine the maximum speed, not less than five miles per
hour, which can be maintained with safety to any bridge, elevated
structure, tube, or tunnel under its jurisdiction, or may request the
Department of Transportation to make such determination.




22404.  The Department of Transportation or local authority making a
determination of the maximum safe speed upon a bridge, elevated
structure, tube, or tunnel shall first make an engineering
investigation and shall hold a public hearing.
   Notice of the time and place of the public hearing shall be posted
upon the bridge, elevated structure, tube, or tunnel at least five
days before the date fixed for the hearing.  Upon the basis of the
investigation and all evidence presented at the hearing, the
department or local authority shall determine by order in writing the
maximum speed which can be maintained with safety to the bridge,
elevated structure, tube or tunnel.  Thereupon, the authority having
jurisdiction over the bridge, elevated structure, tube, or tunnel
shall erect and maintain suitable signs specifying the maximum speed
so determined at a distance of not more than 500 feet from each end
of the bridge, elevated structure, tube, tunnel, or any approach
thereto.



22405.  (a) No person shall drive a vehicle on any bridge, elevated
structure, tube, or tunnel constituting a part of a highway, at a
speed which is greater than the maximum speed which can be maintained
with safety to such structure.
   (b) Upon the trial of any person charged with a violation of this
section with respect to a sign erected under Section 22404, proof of
the determination of the maximum speed by the Department of
Transportation or local authority and the erection and maintenance of
the speed signs shall constitute prima facie evidence of the maximum
speed which can be maintained with safety to the bridge, elevated
structure, tube, or tunnel.



22406.  No person may drive any of the following vehicles on a
highway at a speed in excess of 55 miles per hour:
   (a) A motortruck or truck tractor having three or more axles or
any motortruck or truck tractor drawing any other vehicle.
   (b) A passenger vehicle or bus drawing any other vehicle.
   (c) A schoolbus transporting any school pupil.
   (d) A farm labor vehicle when transporting passengers.
   (e) A vehicle transporting explosives.
   (f) A trailer bus, as defined in Section 636.



22406.1.  Any person who operates a commercial motor vehicle, as
defined in Section 15210, upon a highway at a speed exceeding a
maximum speed limit established under this code by 15 miles per hour
or more, is guilty of a misdemeanor.  A violation of this section
shall be considered a "serious traffic violation," as defined in
subdivision (i) of Section 15210, and shall be subject to the
sanctions provided under Section 15306 or 15308, in addition to any
other penalty provided by law.



22406.5.  Any person who drives a tank vehicle subject to Division
14.7 (commencing with Section 34000) while transporting more than 500
gallons of flammable liquid at a speed greater than the applicable
speed limit or in willful or wanton disregard for the safety of
persons or property is, in addition to any other applicable penalty,
subject to a fine of not less than five hundred dollars ($500) for a
first offense and, for a second or subsequent offense within two
years of a prior offense, to a fine of not less than two thousand
dollars ($2,000) and a suspension of up to six months of a hazardous
materials or cargo tank endorsement, or both.



22407.  Whenever the Department of Transportation or local authority
determines upon the basis of engineering studies and a traffic
survey that the speed of 55 miles per hour is more than is reasonable
or safe for vehicles mentioned in subdivision (a) of Section 22406,
which have a manufacturer's gross vehicle weight rating of 10,000
pounds or more, in descending a grade upon any portion of a highway,
the department or local authority, with respect to highways under
their respective jurisdiction, may determine and declare a speed
limit of 50, 45, 40, 35, 30, 25, or 20 miles per hour, whichever is
found most appropriate to facilitate the orderly movement of traffic
and is reasonable and safe, which declared speed limit shall be
effective for such vehicles when appropriate signs giving notice
thereof are erected upon the highway.



22409.  No person shall operate any vehicle equipped with any solid
tire when such vehicle has a gross weight as set forth in the
following table at any speed in excess of the speed set forth
opposite such gross weight:


      When gross weight                              Maximum speed
       of vehicle and                                  in miles
          load is:                                      per hour:
      10,000 lbs.  or more but less than 16,000 lbs.  ....   25
      16,000 lbs.  or more but less than 22,000 lbs.  ....   15
      22,000 lbs.  or more ..............................   12



22410.  No person shall operate any vehicle equipped with any metal
tire in contact with the surface of the highway at a speed in excess
of six miles per hour.



22411.  No person shall operate a motorized scooter at a speed in
excess of 15 miles per hour.



22413.  Whenever a local authority determines upon the basis of an
engineering and traffic survey that the prima facie limit of 25 miles
per hour is more than is reasonable and safe on any portion of a
street having a grade in excess of 10 percent, the local authority
may by ordinance determine and declare a maximum limit of 20 or 15
miles per hour, whichever is found most appropriate and is reasonable
and safe.  The declared maximum speed shall be effective when
appropriate signs giving notice thereof are erected upon the street.