The following are some of the interpretations of terms used in The Vehicle Weight and Dimension Regulations.

"Act" means The Highways and Transportation Act, 1997.

"A-dolly" means a converter dolly that is towed from a single hitch located on the towing vehicle.

"Articulated bus" means a bus:

1. with an articulation point between the passenger-carrying sections of the vehicle;
2. designed so that movement of passengers between the sections of the vehicle is possible at all times while the bus is operated on a highway.

"A train" means a combination of vehicles composed of a truck tractor and a semi-trailer towing either:

1. a semi-trailer with an A-dolly; or
2. a full trailer attached to the lead semi-trailer in the same manner as if an A-dolly were being used.

"Axle" means an assembly of two or more wheels, which have a common axis of rotation, through which weight is transmitted to a public highway.

"Axle group" means any number of consecutive axles on a vehicle through which weight is to be equally distributed and transmitted to a highway so that the difference in weight on each axle in any axle group is not more than 1,000 kg from an adjacent axle.

"Axle spread" means the distance between the extreme axle centres of an axle group.

"Axle unit" means:

1. a multiple axle group;
2. a single axle;
3. a single-half axle unit;
4. a tandem axle group;
5. a tandem drive axle group;
6. a tridem axle group;
7. a tridem drive axle group; or
8. a wide-spread tandem axle group.

"Box length" means:

1. for a semi-trailer, subject to subclauses (ii) and (iii), the distance from the front of the semi-trailer to its rear, including the load but not including auxiliary equipment;
2. for an A-train, B-train or C-train, the distance from the front of the lead semi-trailer to the rear of the rearmost vehicle in the A-train, B-train or C-train, including the load but not including auxiliary equipment mounted on the lead semi-trailer; or
3. for a truck and trailer combination, the distance from the front of the load carrying area on the truck to the rear of the rearmost vehicle in the truck and trailer combination, including the load but not including auxiliary equipment.

"B-train" means a combination of vehicles composed of a tractor and a semi-trailer towing another semi-trailer attached to a fifth-wheel mounted on the rear of the first semi-trailer.

"Bus" means a motor vehicle designed and intended to carry more than 15 passengers.

"C-dolly" a converter dolly that:

1. has two parallel arms that connect to two hitches located on a towing unit so as to prevent any rotation in a horizontal plane through the hitch points;
2. has drawbars that are within three degrees of level;
3. meets the C-dolly specifications set out in Standard 903 of the Canadian Motor Vehicle Safety Standards, being SOR/93-146; and
4. is used with the dolly axle locked in the zero steer position at all times while travelling if:
   1. one or more of the axle locking mechanisms are not in working condition; or
   2. the C-train is operated at a speed in excess of 50 km/h on any surface other than a dry, paved road.

"Combination of vehicles" means two or more vehicles joined together.

"Combined weight" means the sum of the gross weight for two adjacent axle units.

"Converter dolly" means a device consisting of one or more axles, a fifthwheel assembly and one or more drawbars used to convert a semi-trailer to a full trailer.

"C-train" means a combination of vehicles composed of a tractor and semi-trailer towing a full trailer connected with a C-dolly.

"Drawbar length" means the distance from the mid-point of the axle unit on a converter dolly to the hitch point on the vehicle towing the trailer.

"Effective overhang" means the greater of the following:

1. the distance from the turn centre to the rearmost point of the truck, trailer or semi-trailer;
2. if there is a load on the truck, trailer or semi-trailer, the distance from the turn centre to the rearmost point of the load.

"End dump semi-trailer" means a semi-trailer designed so that its cargo carrying area may be raised to allow the end dumping of its load.

“Farm equipment” means equipment that is designed and intended for use in farming operations but does not include any of the following:

1. a truck;
2. a semi-trailer;
3. a full trailer;
4. a pony trailer;
5. farm equipment that is loaded on a truck, trailer or semi-trailer; or
6. farm equipment that is towing equipment other than farm equipment.

“Fifth wheel assembly” means a coupling device that:

1. is securely attached to the chassis of a vehicle; and
2. consists of a skid plate, associated mounting brackets and a latching mechanism that couples or connects to a kingpin located on the other vehicles or component of the other vehicles, for the purpose of supporting or towing a semi-trailer.

“Full trailer” means a vehicle that is designed to be towed by another vehicle and is designed so that the whole of its weight is carried on its own axles and includes a semi-trailer and a converter dolly hitched together, but does not include:

1. recreational vehicles;
2. agricultural implements;
3. timbers or metal beams with wheels attached and used for the purpose of moving buildings;
4. asphalt distributors used for the construction or maintenance of bituminous surfaced highways; or
5. pony trailers.

"Gross vehicle weight" means:

1. the combined weight of a vehicle and the load carried on that vehicle; or
2. the combined weight of two or more vehicles coupled or joined together and the combined weight of the loads carried on each of those vehicles.

"Gross weight" means the weight transmitted to the surface of a public highway through any areas on contact between the roadway surface and any vehicle, object or contrivance.

"Hitch offset" means the distance from the trailer turn centre to the hitch point used to tow a trailer.

"House trailer" means a vehicle drawn by a motor vehicle and designed and intended for use as living quarters or for office space.

"Interaxle spacing" means the distance separating centres of the nearest axles in two adjacent axle units.

"Kingpin setback" means the longitudinal distance from the centre of the kingpin on a semi-trailer to any point on the semi-trailer, including its load, in front of the kingpin measured in the arc from the centre of the kingpin to the most distant point on the trailer or load in front of the kingpin excluding any auxiliary equipment, heater or refrigeration unit or aerodynamic device that is attached to the front of the semi-trailer and that is not designed for the transportation of goods.

"Lift axle" means an axle of a vehicle that is constructed with a device capable of raising the wheels on that axle from contact with the highway.

"Motor vehicle" means a vehicle propelled by or driven by any means other than by muscular power.

"Multiple axle group" means an axle group of three or more axles with an axle spread of not more than 4.5 m, but does not include a tridem axle group.

"Pony trailer" means a vehicle that is:

1. designed and intended to be towed by another vehicle;
2. designed so that most of its weight is carried on its axles;
3. equipped with a rigid drawbar; and
4. equipped with only one axle unit.

"Provincial road" means any public highway shown as a provincial road on the current official highway map.

"Road construction and maintenance equipment" means self-propelled or towed equipment used directly in road construction or maintenance, but does not include a truck, trailer, semi-trailer or any road construction or maintenance equipment transported on a truck, trailer or semi-trailer.

"Semi-trailer"means a vehicle with one axle unit that is designed for the transportation of goods and that is intended to be towed by another vehicle in a manner so that a substantial part of the weight of the vehicle being towed rests on or is being carried by the towing vehicle or trailer converter dolly through a fifth wheel assembly, but does not include:

1. a recreational vehicle;
2. an agricultural implement;
3. timbers or metal beams with wheels attached that are used for the purpose of moving buildings;
4. an asphalt distributor used for the construction or maintenance of
   bituminous surfaced highways;
5. a converter dolly; or
6. a pony trailer.

"Single axle" means:

1. any individual axle; or
2. any combination of two or more axles whose centres are less than 1 m apart, but does not include any axle within a tandem, wide-spread tandem, tridem or multiple axle group.

"Single-half axle unit" means a group of two axles with four wheels on one axle and two single wheels on the second axle:

1. whose centres are not less than 1 m and not more than 1.85 m apart; and
2. that is not subject to the axle group weight distribution requirements for adjacent axles.

"Steering axle" means an articulated lead axle of a motor vehicle which governs the direction travelled by the motor vehicle.

1. the articulated axle or axles of a motor vehicle that are controlled by the vehicle operator and govern the direction travelled by the motor vehicle; or
2. an articulated axle on a trailer or semi-trailer where the direction of travel of the trailer is governed by the towing unit.

"Tandem axle group" means a group of two axles:

1. whose centres are more than 1 m and not more than 1.85 m apart; and
2. that is not part of a tridem axle or a multiple axle group.

"Tandem drive axle group" means a tandem axle group in which one or both axles in the group are connected to a power source that transmits tractive power to all wheels on that axle or those axles.

"Track width" means the overall width of an axle measured from the outside of the outside tire located on one side of the vehicle to the outside of the outside tire located on that axle on the other side of the vehicle at any point above the lowest point of the rim.

"Tractor" means a motor vehicle designed, and normally used, to pull a semi-trailer (also known as a power unit).

"Trailer" means a vehicle without motive power that is designed to be towed by another vehicle.

“Trailer wheelbase” means, in the case of a vehicle with a gross vehicle weight exceeding 4,500 kg, the longitudinal distance from the turn centre of the vehicle to:

1. the centre of the kingpin of a semi-trailer;
2. the centre of the turntable of a full trailer; or
3. the centre of the hitching device of a pony trailer.

"Tridem drive axle group" means a tridem axle group in which all axles in the group are connected to a power source that transmits tractive power to all wheels on those axles.

"Truck" means a motor vehicle that:

1. is permanently fitted with a special purpose device for the transportation of goods; or
2. is designed and normally used for the transportation of goods.

“Truck wheelbase or truck tractor wheelbase” means the longitudinal distance from the centre of the steering axle unit to the geometric centre of the drive axle unit.

"Urban municipality" means:

1. a city as defined in The Cities Act;
2. a village, resort village or town as defined in The Municipalities Act; or
3. a northern hamlet, northern village or town as defined in The Northern Municipalities Act.

"Vehicle" means a device or object in, on or by which a person or thing is, or may be, transported on a highway and includes:

1. any load on, or equipment attached to the vehicle; and
2. any equipment that may be towed on a highway.