Maine's term is "all-terrain vehicle" or "ATV": a motor-driven, off-road, recreational vehicle that was originally designed by the manufacturer for and is capable of cross-country travel. The definition includes, but is not limited to, a motorcycle or related 2-wheel, 3-wheel or belt-driven vehicle, or other means of transportation deriving motive power from a source other than muscle or wind. For purposes of that subpart, the term does not include a motor vehicle as defined in Title 29-A, section 101, subsection 42.
A person may not operate an ATV, a term that includes a motorcycle or related 2-wheel vehicle, that is not registered under section 13155, with listed exceptions. The registration number, in the form of stickers, must be clearly displayed on the front and rear of the vehicle, and an annual registration is valid for one year commencing July 1st. The exceptions are: an ATV operated on land that the operator owns or leases, as long as it is not operated elsewhere within the jurisdiction of the State; an ATV registered in another state or a Canadian province at a special event the commissioner has approved on the organizer's written request; ATVs used exclusively for scheduled racing meets and operated solely on predefined race courses, during the meets and prerace practices; commercial ski area snow packing or rescue; farm-use vehicles registered with the Secretary of State under Title 29-A, section 501, subsection 8; manufacturer demonstration events approved by the commissioner; and an oversized ATV (wider than 65 inches or more than 2,000 pounds) used solely in a business activity on the land of another with written permission. A government-owned ATV is exempt from registration fees but must be registered. A nonresident registration is $100 for 7 consecutive days or $115 for one year; the commissioner may also annually establish one 3-consecutive-day period during which a nonresident with a valid registration from another state or a Canadian province may operate an ATV not registered in Maine.
A person under 18 years of age may not operate an ATV, a term that includes a motorcycle or related 2-wheel vehicle, without protective headgear. A person may not carry a passenger under 18 years of age on an ATV unless the passenger is wearing protective headgear.
A person under 10 years of age may not operate an ATV, a term that includes a motorcycle or related 2-wheel vehicle. A person 10 or older but under 16 may not operate an ATV unless that person has successfully completed a training course approved by the department and is accompanied by an adult; proof of completing the course must be presented on request of a law enforcement officer. A person under 16 may not cross a public way maintained for travel unless the crossing follows section 13157-A, subsection 6, paragraph A and the person meets the training and adult requirements. These rules do not apply on the land on which the operator is domiciled, on land owned or leased by the operator's parent or guardian, or at a safety training site approved by the department.
A person may not operate an ATV, a term that includes a motorcycle or related 2-wheel vehicle, on any portion of a public way maintained or used for the operation of conventional motor vehicles, or on the sidewalks of any public way, unless the ATV is registered with the Secretary of State under Title 29-A or a listed exception applies. A properly registered ATV may go on a public way only the distance necessary, never more than 500 yards, on the extreme right of the traveled way, to cross as directly as possible, as long as that can be done safely and does not interfere with approaching traffic. The other listed exceptions are: a public way closed under Title 23, section 2953; a public way not maintained or used for conventional motor vehicles (not on the left side from sunset to sunrise); an emergency declared by a police agency when conventional motor vehicle travel is not practicable; special events of limited duration under a permit from the governmental unit having jurisdiction; a law enforcement officer traveling to a patrol area; and a public way the appropriate governmental unit has designated and posted as an ATV-access route, where the ATV must travel in the same direction as motor vehicle traffic. A person must bring an ATV to a complete stop before entering a public way and must yield the right-of-way to all other vehicular traffic. On a controlled access highway or within its right-of-way limits, a person may not operate an ATV except, on a properly registered ATV, to cross by bridges over, roads under or roads crossing the highway at grade or to use an approved trail segment, or at a designated crossing under a special permit from the Commissioner of Transportation.
An electric bicycle is a 2-wheel or 3-wheel bicycle with fully operable pedals and an electric motor of less than 750 watts that is a Class 1, Class 2 or Class 3 electric bicycle. Class 1 and Class 3 motors provide assistance only when the rider is pedaling and cease to assist at 20 and 28 miles per hour respectively; a Class 2 motor is capable of being used exclusively to propel the bicycle but is not capable of propelling it at a speed of 20 miles per hour. A motorcycle is a motor vehicle with a seat or saddle, designed to travel with only 2 or 3 wheels of 10-inch or larger diameter in ground contact, with a motor of more than 50 cubic centimeters or an electric motor with a capacity of not less than 1,500 watts.
This page restates state law in plain words and links the text it came from. It is not legal advice. Cities, counties and the agencies that manage federal land (the Bureau of Land Management and the Forest Service) add rules of their own, so check with whoever manages the ground you plan to ride.