California Code, Vehicle Code - VEH § 17707

Any civil liability of a minor arising out of his driving a motor vehicle upon a highway during his minority is hereby imposed upon the person who signed and verified the application of the minor for a license and the person shall be jointly and severally liable with the minor for any damages proximately resulting from the negligent or wrongful act or omission of the minor in driving a motor vehicle, except that an employer signing the application shall be subject to the provisions of this section only if an unrestricted driver's license has been issued to the minor pursuant to the employer's written authorization.

No liability may be imposed under this section or under Section 17708 on the state or county, or on a probation officer or child protective services worker acting as an officer of the court for damages caused solely by the negligence or willful misconduct of a minor driver whose application for a driver's license was signed by the child protective services worker or probation officer while the minor was a dependent or ward of the court.