When You Need a Trip Permit vs an IRP Plate in Washington

Nov. 5, 2025, 7:16 p.m.
Here’s a detailed breakdown of when you need a **International Registration Plan (IRP) plate vs. a **Trip Permit in Washington for commercial vehicles:
When You Need a Trip Permit vs an IRP Plate in Washington

When an IRP Plate Is Required

According to the Washington State Department of Licensing (DOL) for the IRP (prorate) program:

  • If you operate a vehicle that has a gross vehicle weight (GVW) of 26,000 pounds or more and the vehicle operates in two or more jurisdictions (states/provinces) you must register under IRP.  

  • Also required if the vehicle has three or more axles, regardless of weight, when traveling in two or more jurisdictions.  

  • Once registered under IRP, you receive apportioned plates and a “cab card” listing the jurisdictions where you may operate.  

So: If you’re operating interstate (or into Canada) with a heavy vehicle meeting these criteria, IRP is the correct registration path.

 When a Trip Permit Is Appropriate Instead

A Trip Permit may apply when you do not have IRP plates but are entering Washington (or passing through) under certain conditions. For example:

  • According to the DOL page for “Trip permits for unlicensed vehicles,” such permits allow “unlicensed vehicles” to operate temporarily — including when the vehicle tabs are expired or the current gross weight license isn’t adequate.  

  • Permit-service sources state that Washington requires a trip permit if the vehicle (or combination) is not IRP-registered and one of these applies:

    • The vehicle has 3 or more axles. 

    • The vehicle has a gross weight (or combination and registered weight) over 26,000 lbs.  

    • The tow vehicle plus trailer combo exceeds 26,000 lbs gross/registered weight. 

Thus: If you’re an out-of-state carrier without IRP credentials and your vehicle meets those thresholds, you’d likely need a trip permit for Washington instead of (or prior to) going full IRP.

 Key Comparison Table

Situation Use IRP Plate Use Trip Permit
Vehicle operates in 2 or more jurisdictions (states/provinces) Required (if weight/axle threshold met) —
Vehicle stays only in Washington or home state Possibly intrastate only => IRP not required Possibly — if no IRP and thresholds met
Vehicle has 3 or more axles IRP likely required if interstate Trip permit may apply if no IRP and only transient
Vehicle gross/registered weight > 26,000 lbs (or combo > 26,000) IRP required if multiple jurisdictions Trip permit may apply if single trip/transit and no IRP
Vehicle has IRP plates already Use IRP credential Trip permit not needed (for that credential)
Vehicle is going through Washington temporarily, not based there Trip permit may suffice (rather than full IRP setup) Applicable

 Practical Tips

  • Always check: “Is the vehicle based in my home state, and do I travel regularly in multiple states?” If yes, IRP is the logical route.

  • If you’re making a one-time or limited trip into/through Washington with a heavy truck and you don’t have IRP, then a Trip Permit may be the compliant, simpler solution.

  • Keep clear records: mileage, jurisdictions traveled, weight/axle counts — especially for IRP. Washington requires that kind of detail.  

  • Make sure to fill out the Trip Permit correctly (vehicle number, dates, weight, etc.) — mistakes could invalidate it.  

  • If you plan to operate regularly across multiple states, it’s often more cost-effective and efficient to convert to IRP rather than repeatedly getting trip permits.