Massachusetts laws pertaining to cyclists are included in the General Laws of the Commonwealth of Massachusetts:
Chapter 85, Section 11a
Chapter 85, Section 11b
Chapter 85, Section 11c
Chapter 85, Section 11d
Chapter 90e, Section 1
Chapter 90e, Section 2
Chapter 90e, Section 2A
Chapter 90, Section 2A
Chapter 90, Section 3

Within the State of Massachusetts, a cyclist's rights allow:

• Riding on any public road, street, or bikeway in the Commonwealth, except limited access or express state highways where signs specifically prohibiting bikes have been posted.
• Riding on sidewalks outside business districts, unless local laws prohibit sidewalk riding.
• Using either hand to signal stops and turns.
• Passing cars on the right.
• Children or other passengers inside an enclosed trailer or other device that will adequately restrain them and protect their heads in a crash need not wear helmets.
• A bicycle race may be held on any public road or street in the Commonwealth, if done in cooperation with a recognized bicycle organization and with approval from the appropriate police department before the race is held.
• Special bike regulations may be established for races by agreement between your bicycle organization and the police.
• As many lights and reflectors are allowed on your bike as you wish.

As a cyclist within the State of Massachusetts, your responsibilities include:

• Obeying all traffic laws and regulations of the Commonwealth.
• Using hand signals to let people know you plan stop or turn.
• Allowing pedestrians the right of way.
• Giving pedestrians an audible signal before overtaking or passing them.
• Riding single file unless passing.
• Riding astride a regular, permanent seat that is attached to your bicycle.
• Keeping one hand on your handlebars at all times.
• Wearing a helmet that meets ANSI requirements on any bike, anywhere, at all times ff you are 16 years old or younger. The helmet must fit your head and the chin strap must be fastened.
• Using a headlight and taillight if you are riding anytime from 1/2 hour after sunset until 1/2 hour before sunrise.
• Wearing reflectors on both ankles if there are no reflectors on your pedals.
• Notifying notify the police of any accident involving personal injury or property damage over $100.

As a cyclist within the State of Massachusetts, you are NOT allowed to:

• Carry a passenger anywhere on your bike except on a regular seat permanently attached to the bike, or to a trailer towed by the bike.
• Carry any child between the ages of 1 to 4, or weighing 40 pounds or less, anywhere on a single-passenger bike except in a baby seat attached to the bike. The child must be able to sit upright in the seat and must be held in the seat by a harness or seatbelt. Their hands and feet must be out of reach of the wheel spokes.
• Carry any child under the age of 1 on your bike, even in a baby seat; this does not preclude carrying them in a trailer.
• Use a siren or whistle on your bike to warn pedestrians.
• Park your bike on a street, road, bikeway or sidewalk where it will be in other people's way.
• Carry anything on your bike unless it is in a basket, rack, bag, or trailer designed for the purpose.
• Modify bike so that your hands are higher than your shoulders when gripping the handlebars.
• Alter the fork of your bike to extend it.

As a cyclist within the State of Massachusetts, your bicycle must be equipped in the following manner:

• A permanent, regular seat must be attached.
• Brakes must be effective enough to bring you to a stop, from a speed of 15 miles an hour, within 30 feet of braking. This distance assumes a dry, clean, hard, level surface.
• At night, your headlight must emit a white light visible from a distance of at least 500 feet. A generator-powered lamp that shines only when the bike is moving is acceptable.
• At night, your taillight must be red and must be visible from a distance of at least 600 feet.
• At night, your reflectors must be visible in the low beams of a car's headlights from a distance of at least 600 feet. Reflectors and reflective material on your bike must be visible from the back and sides.

Penalties:

• Violations of any of these laws can be punished by a fine of up to $20. Parents and guardians are responsible for cyclists under the age of 18. The bicycle of anyone under 18 who violates the law can be impounded by the police or town selectmen for up to 15 days.