What is a Double Trailer Permit?
The Double Trailer Monthly/Annual Permit is issued by the Washington State Department of Transportation and allows trucks with double trailers to exceed the standard legal length.
- Legal double trailer length: 61 feet
- With permit: up to 68 feet total length
What this permit allows
- Hauling divisible or non-divisible loads on double trailers
- Extending total combination length up to 68 ft
- Operating with fewer restrictions compared to trip permits
Permit duration options
You can choose based on your operation:
- Monthly Permit: Valid for 30 days
- Annual Permit: Valid for 1 year
Cost
- $100 per month
- $1000 per year
(Very cost-effective for frequent haulers compared to trip permits.)
Key benefits
This permit is exempt from several common restrictions:
- No commuter hour or holiday travel restrictions
- No oversize signs required
- No night travel restrictions
- Allowed during winter restrictions (must still follow chain requirements)
When you need it
You should get this permit if:
- Your double trailer setup exceeds 61 ft length
- You haul regular loads requiring extra length
- You want a long-term, low-cost permit instead of repeated trip permits
Simple example
If your double trailer combination measures 65 feet:
- You cannot operate legally without a permit
- A monthly or annual permit allows legal operation up to 68 feet