Cal. Veh. Code § 17155
If two or more persons are injured or killed in one accident, the owner, bailee of an owner, or personal representative of a decedent may settle and pay any bona fide claims for damages arising out of personal injuries or death, whether reduced by judgment or not, and the payments shall diminish, to the extent of those payments, the person's total liability on account of the accident. Payments aggregating the full sum of thirty thousand dollars ($30,000) shall extinguish all liability of the owner, bailee of an owner, or personal representative of a decedent for death or personal injury arising out of the accident that exists pursuant to this chapter, and did not arise through the negligent or wrongful act or omission of the owner, bailee of an owner, or personal representative of a decedent nor through the relationship of principal and agent or master and servant.
Ca. Veh. Code § 17155