The gross vehicle weight rating (GVWR), or gross vehicle mass (GVM) is the maximum operating weight/mass of a vehicle as specified by the manufacturer including the vehicle's chassis, body, engine, engine fluids, fuel, accessories, driver, passengers and cargo but excluding that of any trailers. The term is used for motor vehicles and trains.
The weight of a vehicle is influenced by passengers, cargo, even fuel level, so a number of terms are used to express the weight of a vehicle in a designated state. Gross combined weight rating refers to the total mass of a vehicle, including all trailers. GVWR and GCWR both describe a vehicle that is in operation and are used to specify weight limitations and restrictions. Curb weight describes a vehicle which is "parked at the curb" and excludes the weight of any occupants or cargo. Dry weight further excludes the weight of all consumables, such as fuel and oils. Gross trailer weight rating specifies the maximum weight of a trailer and the gross axle weight rating specifies the maximum weight on any particular axle.
An axle is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to its surroundings, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle is supported. In the latter case, a bearing or bushing sits inside the hole in the wheel to allow the wheel or gear to rotate around the axle. Sometimes, especially on bicycles, the latter type is referred to as a spindle.
On cars and trucks, several senses of the word "Tandem axle" co-occur in casual usage, referring to the shaft itself, its housing, or simply any transverse pair of wheels. The shaft itself rotates with the wheel, being either bolted or splined in fixed relation to it, and is called an "axle" or "axle shaft". However, it is equally true that the surrounding housing (typically a casting) is also called an "axle" (or "axle housing"). An even broader (somewhat figurative) sense of the word refers to every transverse pair of wheels, whether they are connected to each other or not. Thus even transverse pairs of wheels in an independent suspension are usually called "an axle".
Truck classifications are typically based upon the maximum loaded weight of the truck (typically using the gross vehicle weight rating (GVWR) and sometimes also the gross trailer weight rating (GTWR)), and can vary from jurisdiction to jurisdiction.
Vehicle classifications vary among provinces in Canada, due to "differences in size and weight regulations, economic activity, physical environment, and other issues".:3 While several provinces use their own classification schemes for traffic monitoring, Manitoba, Ontario, Prince Edward Island and Saskatchewan have adopted the 13-class system from the United States' Federal Highway Administration—sometimes with modifications, or in Ontario's case, for limited purposes.:3–4]dated info[ British Columbia and Ontario also distinguish between short- and long-combination trucks.:3–4]dated info[ In accident reporting, eight jurisdictions subdivide trucks by GVWR into light and heavy classes at approximately 4500 kg 9921 lb).:6
In motor vehicles, the gross trailer weight rating (GTWR) is the total mass of a road trailer that is loaded to capacity, including the weight of the trailer itself, plus fluids, and cargo, that a vehicle is rated to tow by the manufacturer. In the United States and Canada, the static tongue load, the weight of the trailer as measured at the trailer coupling, is generally recommended to be 10-15% of the GTWR.
In the United States and Canada, there are four main weight classes of trailer hitches as defined by the Society of Automotive Engineers (SAE):
Road transport (British English) or road transportation (American English) is the transport of passengers or goods on roads.
The first methods of road transport were horses, oxen or even humans carrying goods over dirt tracks that often followed game trails. As commerce increased, the tracks were often flattened or widened to accommodate the activities. Later, the travois, a frame used to drag loads, was developed. The wheel came still later, probably preceded by the use of logs as rollers. Early stone-paved roads were built in Mesopotamia and the Indus Valley Civilization. The Persians later built a network of Royal Roads across their empire.