just info I found...
Side-by-Side Off Road vehicles (MTO site http://www.mto.gov.on.ca/english/pubs/a ... side.shtml)
•A side-by-side off-road vehicle has driver and passenger seating beside each other, similar to a car. It is usually built with a hood, a steering wheel and foot pedals, instead of a motorcycle-type handle bar and thumb throttle.
• A side-by-side off-road vehicle must be registered and display a rear licence plate, except in exempt areas such as far northern Ontario. It must be insured under a motor vehicle liability policy
• A side-by-side off-road vehicle is prohibited from use on provincial highways and municipal roads
• A side-by-side off-road vehicle can travel directly across a highway (where permitted), if the driver is at least 16 years of age and holds a valid drivers licence.
ATV (MTO site http://www.mto.gov.on.ca/english/pubs/a ... ding.shtml)
•As described in the "Off-Road Riding" section, an ATV must be registered and insured.
•An ATV that weighs 450 kilograms or less and has an overall width not greater that 1.35 m (excluding mirrors) may travel along some provincial highways and on municipal roads, only if the municipality has a bylaw permitting their use.
• An ATV is allowed to travel on Highways 500 to 899, 7000 series highways and highways with low traffic volumes, but is prohibited from traveling on 400 series highways, the Queen Elizabeth Way, and sections of the Trans-Canada Highway
Two-Up ATVs (MTO site http://www.mto.gov.on.ca/english/pubs/a ... ATVs.shtml)
• A two-up ATV is a type of off-road vehicle that has four wheels, steering handlebars, a drivers seat and a passenger seat directly behind the driver.
Note: a single rider ATV that has been modified to carry a passenger by installing an after-market seat and foot pegs is not considered to be a two-up ATV.
• A two-up ATV must be registered and display a rear licence plate. It must also be insured under a motor vehicle liability policy.
• A two-up ATV is prohibited from provincial highways and municipal roads, even if the driver is not carrying a passenger.
• A two-up ATV can be driven directly across a highway (where permitted), if the driver is 16 years of age and holds a valid drivers licence.
HTA OREG 316/03 "all-terrain vehicle" means an off-road vehicle that,
(a) has four wheels, the tires of all of which are in contact with the ground,
(b) has steering handlebars,
(c) has a seat that is designed to be straddled by the driver, and
(d) is designed to carry a driver only and no passengers