2005 California Vehicle Code Sections 28100-28103 Article 15. Pilot Cars

28100.  A pilot car shall display at least one red warning flag on
each side of the vehicle.  The flags shall be a minimum of 16 inches
square, and shall be mounted so as to be visible from both the front
and rear of the vehicle.  The flags shall be removed or covered when
the vehicle is not operating as a pilot car.
28101.  In addition to the lighting, sign, and flag requirements in
Sections 25270, 27904, 27904.5, and 28100, a pilot car shall meet all
of the following requirements:
   (a) Be a vehicle not less than 60 inches in width.
   (b) Be equipped with all of the following:
   (1) One STOP/SLOW paddle.
   (2) One orange vest, shirt, or jacket.
   (3) One red hand flag (24 inches square).
   (4) One two-way radio communication device.
28102.  Pilot cars equipped with vertical clearance measuring
devices shall comply with Section 35252.
28103.  It is unlawful and an infraction for any person to violate
any provision of this article or to fail to have any required
equipment in good working order.