Oversize & Overweight Permits: US States and Canadian Provinces

Oversize and overweight freight is one of the most complex areas in brokerage. Two different regulatory systems — federal and state in the US, federal and provincial in Canada — overlap in ways that catch brokers off guard. This guide covers the legal limits, what triggers a permit, annual permit programs in each Canadian province, key state-by-state restrictions, spring weight bans, and pilot car rules.

What Triggers an OS/OW Permit

A permit is required any time a load exceeds the legal limit for any single dimension or weight threshold — it only takes one. Exceeding width but not height still requires an oversize permit. Exceeding axle weight but not GVW still requires an overweight permit.

US Permit System Overview

The US has no federal oversize/overweight permit system. Each state manages its own permits independently. A load crossing five states requires five separate permits, each applied for through the relevant state DOT or permit office. Some states allow online applications; others require fax or phone.

Permit types vary by state but generally fall into two categories: single-trip permits (one movement, one route, point to point) and annual permits (blanket coverage for a defined category of load or route, renewed yearly). Most brokers deal primarily with single-trip permits.

Superload Thresholds

When a load exceeds certain thresholds — typically over 16 feet wide, over 15 feet tall, or over 200,000 lbs — it becomes a "superload" subject to significantly more scrutiny. Superloads may require:

• Engineering bridge analysis for every bridge on the route
• Utility company coordination (power lines raised or de-energized)
• Law enforcement escort in addition to private pilot cars
• Multi-agency approval involving state DOT, utility companies, and sometimes federal agencies
• Lead times of 2–8 weeks or more depending on states involved
• Route surveys by an escort vehicle before movement begins

Superloads are outside the scope of most freight brokers. They are handled by specialized heavy haul brokers and carriers with engineering resources on staff. If a shipper describes a load that appears to be in superload territory, be honest about whether you have the expertise and carrier relationships to handle it safely.

Canadian Permit System Overview

Canada operates under a similar two-tier system: Transport Canada sets national standards under the Motor Vehicle Transport Act, but provinces regulate permits, weights, and dimensions on their own road networks. Each province issues its own permits.

The western provinces (British Columbia, Alberta, Saskatchewan, Manitoba) have harmonized many of their weight and dimension standards through a Memorandum of Understanding (MOU), which simplifies cross-provincial movements in western Canada. Eastern provinces (Ontario, Quebec, Atlantic) operate largely independently.

Unlike most US states, several Canadian provinces offer annual oversize permits that allow a carrier to make repeated movements of a defined equipment type without filing individual trip permits each time. These are particularly useful for carriers running consistent OD equipment on regular corridors.

Canadian Annual Permit Programs by Province

Spring Weight Restrictions

Spring weight restrictions (also called spring thaw restrictions or frost bans) are among the most disruptive limitations in oversize/overweight trucking — and they affect standard flatbed freight as well, not just permitted loads. When the ground thaws after winter, road surfaces become temporarily unstable and susceptible to damage from heavy axle loads.

Restrictions typically reduce allowable axle weights by 25–50% for a period of 4–12 weeks. The timing and severity depend on the winter and regional conditions, so exact dates vary each year.

Frost law bypass permits exist in some provinces — Alberta and Saskatchewan specifically allow carriers to apply for a permit to move at reduced weight on restricted roads, or to wait for a daily freeze window (early morning movement before the ground thaws for the day). These window movements are common in the oilfield sector.

Pilot Car and Escort Requirements

Pilot car requirements vary by state and province but follow broadly similar thresholds. The widths below are general guidance — confirm with the permit for each state or province on your specific route.

• Pilot car drivers must be licensed as escorts in many states — confirm your carrier uses certified escort services
• Height poles (measuring the load clearance) are required when loads exceed 14'6" in most jurisdictions
• Wind restrictions: wide loads (over 14') are typically prohibited from moving when winds exceed 35–40 mph
• Pilot car rates are typically $2–$5 per loaded mile depending on region and whether police escort is required

Travel Time and Day Restrictions

Nearly all oversize loads face some form of travel time restriction. The most common:

Broker Checklist for OS/OW Loads

1. Get all four dimensions and weight from the shipper — length, width, height, and GVW including the loaded trailer
2. Identify every state and province the route crosses — each needs a separate permit
3. Call the carrier's permit department immediately — do not set a pickup date until you know permit lead times for each jurisdiction
4. Confirm whether an annual permit covers this load or whether single-trip permits are needed in each state/province
5. Check spring weight restriction status if the load is moving in March, April, or May — call the provincial/state DOT if unsure
6. Confirm pilot car requirements for the widest point of the load across all jurisdictions on the route
7. Build realistic transit time: daylight windows + no Sunday travel + permit processing time
8. Ask whether the carrier carries superload capabilities if the load is over 16' wide or approaches 200,000 lbs
9. Confirm the carrier's liability insurance covers the load value — high-value equipment on lowboys often needs excess cargo coverage
10. Communicate the permit restrictions to the shipper before confirming a delivery window — underpromise, then deliver

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