In California, it is illegal to hold your phone in your hand for any reason while in the drivers seat.
Penalties. Unlawful use of a cellphone while driving is an infraction in California. A first offense results in a $20 base fine, and for a second or subsequent offense, the base fine is $50. But be mindful that the actual amount you’ll pay once assessments are added will be significantly more than the base fine. The total for a first violation will likely exceed $150, and a second or subsequent offense can cost over $250. However, unlawful cellphone use is a zero-point traffic violation, so a conviction shouldn't affect a motorist's insurance rates. (Read about
California’s traffic violation point system.)
Exceptions. California’s vehicle cellphone ban doesn’t apply when a motorist uses a cellphone while driving on private property or places a call for emergency purposes (such as calling for an ambulance or other emergency services). Emergency service professionals are also exempt from the cellphone ban while operating an authorized emergency vehicle.
(Cal. Veh. Code §§ 12810.3, 23123 (2017).)