What Is the Oregon Weight–Mile Tax (WMT)

Nov. 13, 2025, 7:41 p.m.
The Oregon Weight–Mile Tax (WMT) is a road usage tax designed specifically for commercial trucks operating in Oregon. Unlike standard fuel taxes, which are based on fuel consumption, the WMT charges vehicles based on how much they weigh and how many miles they travel on Oregon roads. This system ensures that heavier trucks, which cause more wear and tear on roads, contribute proportionally to road maintenance. Here’s a detailed breakdown:
Oregon Weight Mile Tax

1. Who Must Pay the WMT

  • The tax applies to commercial trucks with a gross vehicle weight (GVW) of 26,000 pounds or more, including:

    • Tractors and trailers

    • Straight trucks used for hauling freight or commercial purposes

  • Vehicles registered under the International Registration Plan (IRP) or already paying Oregon fuel taxes may have special rules or exemptions.

2. How the Tax is Calculated

  • The WMT is calculated using a formula based on vehicle weight and miles traveled on Oregon public roads:

    Tax = (Miles traveled in Oregon) × (Weight factor rate)

  • Weight factor: Heavier trucks pay more per mile than lighter trucks.

  • Trucks must report mileage for the current tax year, and rates are periodically adjusted by the Oregon Department of Transportation (ODOT).

3. Registration and Reporting

  • Truck owners must register annually with ODOT for a WMT account.

  • Trucks report Oregon miles traveled, either by:

    • Mileage reporting forms (for smaller fleets)

    • Electronic logging systems (for larger fleets)

  • Payment is usually annually or quarterly depending on mileage.

4. Exemptions & Credits

  • Trucks registered in Oregon and paying the Oregon fuel tax may get credits against the WMT to avoid double taxation.

  • Some out-of-state trucks may qualify for reduced rates or exemptions if they already pay equivalent taxes elsewhere.

5. Why the WMT Exists

  • The primary goal is to fund road maintenance fairly:

    • Heavy trucks cause more damage than lighter vehicles.

    • Fuel taxes alone don’t accurately reflect road usage by heavy trucks.

  • Encourages efficient road use and ensures infrastructure sustainability.

Key Takeaway: The Oregon WMT is essentially a “pay-per-mile” tax based on the weight of commercial trucks. Heavier trucks pay more, and all commercial trucks must report their mileage in Oregon to comply.