California Code, Public Utilities Code - PUC § 5434

(a) Nothing in this section shall be construed to require a private passenger automobile insurance policy to provide primary or excess coverage during the period of time from the moment a participating driver in a transportation network company logs on to the transportation network company's online-enabled application or platform until the driver logs off the online-enabled application or platform or the passenger exits the vehicle, whichever is later.

(b) During the period of time from the moment a participating driver in a transportation network company logs on to the transportation network company's online-enabled application or platform until the driver logs off the online-enabled application or platform or the passenger exits the vehicle, whichever is later, all of the following shall apply:

(c) Notwithstanding any other law, a personal automobile insurer may, at its discretion, offer an automobile liability insurance policy, or an amendment or endorsement to an existing policy, that covers a private passenger vehicle, station wagon type vehicle, sport utility vehicle, or similar type of vehicle with a passenger capacity of eight persons or less, including the driver, while used in connection with a transportation network company's online-enabled application or platform only if the policy expressly provides for the coverage during the time period specified in subdivision (b), with or without a separate charge, or the policy contains an amendment or an endorsement to provide that coverage, for which a separately stated premium may be charged.

(d) This section shall become operative on July 1, 2015.