California Motor Vehicle Code 21100.3
Obedience to Person Controlling Traffic
California Vehicle Code 21100.3 states that every driver must obey an authorized traffic officer. However, there is no definition given as to what constitutes an authorized traffic control officer. For the layperson, a traffic control officer could mean anyone from a police officer to a crossing guard to a firefighter working at an accident scene.
The State of California defines an authorized traffic control officer as someone who is "authorized or appointed by a local government authority." In addition to being appointed by local government officials, this person must also be in uniform and/or wearing an official insignia that has been given to them at their time of appointment. Failure to follow the directions of an authorized traffic control officer could result in your receiving a traffic ticket and having one point added to your license.
School crossing guards, firefighters, construction workers, and private citizens directing traffic are not authorized persons for the purpose of CVC 21100.3. Even though the aforementioned persons are not authorized, it is still a good idea to follow the directions of anyone directing traffic. There could be dangerous consequences involved if their directions are ignored. If you decide to ignore anyone directing traffic, you could be charged with reckless driving; especially if there is an injury or property damage.