In a July online interview, Schwarzenegger said he had warned his 16-year-old daughter about driving with her cell phone in hand. He said she would lose her driving privileges if he caught her doing so.

Even though the bill takes effect in 2008, the governor in the signing ceremony urged drivers to "stop using them now. You are putting people at risk. You could kill [a] child just because you were looking down at your phone."

The sponsor of the bill, Sen. Joe Simitian, D-Palo Alto, praised Verizon Wireless and Palm for their support. He said he had introduced the measure six times before succeeding, "simply because it will save people's lives."