What are the bike helmet laws in Palo Alto?

In California, all cyclists and e-bike riders younger than 18 are required by law to wear a properly fastened bike helmet.

Adults in California are not required to wear a helmet while riding a regular bicycle, a Class 1 e-bike, or a Class 2 e-bike.

For Class 3 e-bikes (which can reach 28 mph), helmets are required for all minors and adults.