This is the Massachusetts Helmet Law:

Massachusetts law requires that "a bicycle helmet be worn by a person 16 years of age or under who is riding as a operator or passenger on a bicycle, in-line skates, a scooter, or a skateboard.
 

Helmets Applied Properly Prevent Injury
Keep It Down & Safe

• Helmet straps should meet in a "V" under each ear

• Chin straps should be snug and comfortable under chin: "one finger-width" between strap and chin

• Wear helmet low on forehead no more than "one to two finger-widths" above eyebrows

• helmet should not move side to side or back and forth

Be sure you wear a helmet designed for your sport and check to make sure it fits properly.
Damaged helmets should be replaced. If you fall or have a collision, check your helmet for cracks or dents.

A blow or jolt to the head can cause a type of mild brain injury called a "concussion"

SOME OF THE SYMPTOMS OF CONCUSSION ARE:

• Persistent low-grade headaches or headaches that get worse
• Having more trouble than usual remembering things, concentrating or making decisions
• Feeling tired all the time or cannot be awakened
• Feeling sad, anxious, listless or inconsolably crying
• Becoming easily irritated, agitated or confused
• A child who will not eat

People with a concussion need to be seen by a doctor.