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Idaho is highlighted. Select the other states on your route to compare their limits.
Legal dimensions
| Measure | Legal maximum |
|---|---|
| Width | 8' 6" |
| Height | 14' |
| Length, semi-trailer | 53' |
| Length, single vehicle | 45' |
| Length, overall | 75' |
| Front overhang | 4' |
| Rear overhang | 10' |
Legal weights
| Measure | Legal maximum |
|---|---|
| Gross vehicle weight | 80,000 lbs |
| Gross weight, single vehicle | — |
| Single axle | 20,000 lbs |
| Tandem axle | 34,000 lbs |
| Tridem axle | 42,000 lbs |
| Single axle, non-divisible | — |
| Tandem axle, non-divisible | — |
| Tridem axle, non-divisible | — |
Last checked September 2026. States revise legal limits, and a limit can depend on the road, the axle spacing or the configuration in ways one table cannot capture. Idaho is the authority — use this to plan, and confirm anything you are close to.
Idaho permit offices
Oversize/ Overweight
Oversize / Overweight
- Phone
- (208) 334-8420
- permits@itd.idaho.gov
- Weekdays
- 7:30 AM – 5:00 PM