Yes, it is required to wear a helmet while riding on the back of someone else's motorcycle in California. According to California law, both the operator (rider) and passenger of a motorcycle must wear a helmet that meets the state's safety standards.
California Vehicle Code Section 27803 states: "A driver and any passenger shall wear a safety helmet meeting requirements established pursuant to Section 27802 when riding on a motorcycle, motor-driven cycle, or motorized bicycle."
The helmet must be approved by the Department of Transportation (DOT) and meet the safety standards set by the agency. The helmet should have a DOT sticker or label indicating its compliance with these standards.
Failure to wear a helmet while riding as a passenger on a motorcycle can result in penalties, such as fines, and may also affect insurance coverage in the event of an accident.
It's important to note that helmet laws can change over time, so it's always advisable to consult the latest laws and regulations or contact the California Department of Motor Vehicles (DMV) for the most up-to-date and accurate information.