The 5th District Court of Appeal reversed the conviction of a Fresno man who was given a ticket in January 2012 for looking at a map on his iPhone while stuck in traffic.
The driver, Steven Spriggs, had challenged his $165 fine with an appellate court.
The judges said the law that the California Highway Patrol officer used to give Spriggs a ticket was specifically for people "listening and talking" on cellphones. The court said that the law does not apply to looking at maps on cellphones.
The Associated Press contributed to this report.