Avis' policies for additional drivers in California read:
In California, the following may drive the car with the renters permission, are exempt from the additional driver fee, but must meet all other driver requirements: the renter's employer or fellow employee when on company business and renting under a corporate account; the renter's spouse or domestic partner; child, sibling or grandparent of the renter; the companion driver of a renter with a disability who has completed the non-licensed renter form; for insurance replacement rentals, company employees or family members who are designated on the insurance policy.
Parents are not included but grandparents are? AB 901 do not allow parents or legal guardians to be charged an additional driver fee.
Do free additional drivers need to be explicitly added to the rental agreement or are they included automatically?