Vehicle Weights, Dimensions and Permit Requirements
What this domain tests
This domain tests Ontario legal dimensions, axle and gross weight limits, and when an oversize or overweight permit is required. You need to know the default limits before a permit and the loading mistakes that make a permit irrelevant.
Legal limits without a permit
- Width: 2.6 m (8 ft 6 in).
- Height: 4.15 m (13 ft 8 in), measured from the ground to the highest point of the load.
- Overall length: 23 m (75 ft 6 in) for a tractor-trailer combination; single vehicles are shorter.
- Gross vehicle weight: 63,500 kg for eligible configurations.
- Axle limits commonly applied: steering axle 5,500 kg, single axle 9,000 kg, tandem 18,000 kg, tridem 24,000 kg.
Permits and restrictions
Oversize or overweight moves need an MTO permit, and some loads also need escorts, route surveys, or time-of-day restrictions. Seasonal reduced-load restrictions can lower allowable axle weights even when the vehicle is registered for the normal limit.
Worked example: A five-axle tractor-trailer scales 36,000 kg gross, well under 63,500 kg, but the tandem reads 18,500 kg and the steering axle 5,200 kg. The gross is legal, but the tandem is 500 kg over. Moving load forward can transfer weight off the tandem and onto the steering axle; the driver must re-scale because the steering axle has only 300 kg of reserve.
Traps: measuring height without the load; assuming a permit authorizes an unsafe or improperly distributed load; and ignoring tire ratings, which can be lower than the axle rating.