What Is a Single Trailer Permit?
In Washington, the standard legal trailer length for a single trailer is:
- 53 feet (without a permit)
With a Single Trailer Permit, carriers can operate:
- Up to 56 feet trailer length
This applies to combinations such as a tractor with one semi-trailer carrying divisible loads.
What This Permit Allows
This permit provides flexibility for carriers who need additional trailer length:
- Extend trailer length from 53 ft to 56 ft
- Operate on approved state highways
- Haul divisible loads without needing trip permits each time
Permit Duration Options
Carriers can choose based on their operational needs:
- Monthly Permit: Valid for 30 days
- Annual Permit: Valid for 12 months
This makes it ideal for both short-term and long-term hauling operations.
Cost
- $100 per month
- $1000 per year
These permits are very cost-effective, especially for carriers frequently operating longer trailers.
Key Benefits
The Washington single trailer permit comes with several advantages:
- No oversize load signs required
- No pilot cars needed
- No daylight-only travel restrictions
- Allowed during weekends and holidays
- Can operate during winter months (must still follow chain requirements)
Important Rules
Even with the permit, carriers must still follow:
- Legal weight limits and axle spacing laws
- Approved route restrictions (if applicable)
- General safety and compliance regulations
This permit does not allow overweight operation, only additional length.
When You Need This Permit
You should obtain a Monthly or Annual Single Trailer Permit if:
- Your trailer exceeds 53 feet in length
- You regularly operate within Washington
- You want to avoid purchasing repeated trip permits
Example
If your trailer measures 55 feet:
- You are not legal without a permit
- A monthly or annual permit allows you to operate legally up to 56 feet