Ontario Oversize Load Permits, Regulations & Axle Rules

Ontario's legal dimensions are 2.6 m wide, 4.15 m high, and 12.5 m for a single vehicle (23 m for a combination). Night travel is allowed in two cases: loads up to 3.05 m wide and 25 m long on multi-lane controlled-access highways with a median, or loads up to 4.26 m high and 63,500 kg on any King's highway. Outside those windows you're running daylight.

Ten stat holidays restrict movement: New Year's Day, Family Day, Good Friday, Victoria Day, Canada Day, the August Civic Holiday, Labour Day, Thanksgiving, Christmas, and Boxing Day. On a holiday or its eve, loads within 3.70 m wide on two-lane roads (3.85 m on multi-lane), 25 m long, 4.26 m high, and 63,500 kg may move only between half an hour before sunrise and noon. Larger loads don't move at all. Weekends open up for loads up to 4.99 m wide and 45.75 m long.

Summer adds layers. In Southern Ontario from June through August: no overweight travel Sunday noon to midnight, and no Friday movement from 3:00 PM to midnight (July through August in the North). Any load over 3.70/3.85 m wide, 25 m long, 4.26 m high, or 63,500 kg also hits the GTA curfew: no entry 7:00 to 9:30 AM, no exit 3:30 to 6:30 PM. Travel stops on snow-covered or icy roads or when visibility drops to 500 m or less. Convoys are prohibited; keep loads 45 minutes and 10 km apart.

Ontario's main dimensional relief lives inside the SPIF (Safe, Productive, Infrastructure-Friendly) framework. SPIF-designated configurations earn higher legal limits without a permit: semi-trailers to 16.2 m, combinations to 27.5 m overall, box length to 20 m, and height to 4.3 m, provided the tractor and trailer meet the prescribed wheelbase and axle geometry.

Raw forest products get a width allowance of 2.7 m at the point of origin and 2.8 m at any point in transit, plus a freeze-up gross-weight allowance of 110 percent of the permitted weight. Loose fodder, including round and rectangular hay bales, moves oversize with no permit at all. Farm machinery needs an OS/OW permit once it rides on a plated vehicle or trailer; operating under its own power it is exempt.

Bulldozers with blades attached are permitted up to 4.27 m wide with the blade angled to reduce width. From 4.00 to 4.27 m they need one private escort; above 4.27 m the blade has to come off. Mobile and modular homes longer than 29.25 m cannot travel in convoy and each needs two private escort warning vehicles.

Ontario uses the term Superload for its top tier. A load hits it by crossing any one of three thresholds: over 120,000 kg gross, 5 m or more wide, or 45.75 m or more long. The application goes to the Ministry of Transportation's Weight and Load Engineer along with senior ministry staff. File at least five days before the planned move; processing takes a minimum of three business days and can run to fourteen.

Any gross weight over 120,000 kg requires the applicant to hire a designated consultant engineer to evaluate every bridge on the route and submit that evaluation for ministry approval. The move also needs a Traffic Management Plan and a Certified Superload Escort. The ministry may require a bond or other security to cover potential highway damage. Overweight single-trip permits above 120,000 kg carry a fee of $714.

Ontario's route-survey requirements scale with the load, and clearing them is the carrier's job before the permit issues. Over 120,000 kg, the carrier must engage a designated consultant engineer to evaluate every bridge on the proposed route and submit the results to the ministry.

Superload dimensions (5 m or more wide, or 45.75 m or more long) bring in a Traffic Management Plan; the ministry recommends completing a physical route analysis first to pinpoint where the Certified Superload Escort will manage traffic and to identify emergency laydown locations. Heights of 4.30 m or greater on a float-type trailer require route clearance before the permit issues. Across all permits the carrier accepts responsibility for clearing overhead wires, structures, and railway crossings, including through construction zones.

For most of Ontario there is no police escort requirement. Escorts are civilian private escort warning vehicles, and at the superload level the Certified Superload Escort is a civilian appointee with traffic-direction authority, not a sworn officer.

The one hard police requirement is route-specific. On Highway 144, between the point 20 km north of Highway 17 at Whitson Creek (Chelmsford) and the junction of Highways 144 and 101, the OPP must escort wide loads. A load from 4.00 to 4.56 m wide needs one OPP unit front plus one private escort rear. A load wider than 4.57 m needs two OPP units, one front and one rear. Below that, from 3.66 to 3.99 m wide on that same stretch, two private escorts run without police. This OPP requirement applies only on that Highway 144 segment. Everywhere else in the province, police are present for enforcement, weighing, and inspection only.