This article is from the California Driving (and Surviving) FAQ, by "George J Wu" firstname.lastname@example.org with numerous contributions by others.
The primary duty of CHP officers is enforcement of the vehicle code [Penal
Code 830.2(a)]. The primary duty of CSP officers is to "provide police
services for the protection of state officers, and the protection of state
properties and occupants thereof" [Penal Code 830.2(b)].