Alaska Truck Weight and Size Limits
Legal limits for a truck in Alaska without a permit: Interstate axle and gross weights, height, width, and semitrailer length, each with its official source.
Data pending verification
Some official figures this page relies on haven't been confirmed against the source yet. Don't rely on results here until this notice is gone.
What's pending
- weight-limits/states/alaska
Alaska limits at a glance
Interstate weight limits
Federal law sets the Interstate limits at 20,000 lb on a single axle, 34,000 lb on a tandem, and 80,000 lb gross, with the bridge formula on every axle group (23 CFR 658.17). States may keep higher limits they had before the federal limits took effect ("grandfather rights").
FHWA: no Alaska highways are subject to Interstate System weight limits; all limits come from the state weight formula (tandem 38,000 lb, no stated gross cap).
FHWA on Alaska: Alaska has a grandfather provision under Federal law (23 CFR Part 658, Appendix C) that allows vehicles to operate above 80,000 lbs. on parts of federally funded AK-1, AK-2, and AK-3. See the Routes section for a full description of the routes to which this grandfather provision applies.
Bridge formula check with Alaska limits
A 5-axle tractor-trailer is filled in. Change the spacings and weights to match your rig; the limits for single axles, tandems, and gross are Alaska's Interstate limits (federal limits stand in where a figure is pending).
Your result
Alaska limits off the Interstate
FHWA's summary of Alaska law for trucks in regular operation (no permit), including non-Interstate highways. It reflects state law as of October 1, 2012; check the state for later changes.
- Single axle
- 20,000 lbs.
- Tandem axle
- 38,000 lbs.
- Tridem axle
- 42,000 lbs.
- Gross weight
- No defined upper limit. Gross vehicle weight is limited by the FBF or the summation of axle or axle group limits - whichever is less. Weight limits on axles or axle groups may not exceed the following, and the distance between axles may not be less than the following: / Single Axle: weight (lbs.) - 20,000; distance: 8'1" Minimum spacing* / 2-Axle Group: weight (lbs.) - 38,000; distance: 3'6" Minimum spacing / 3-Axle Group: weight (lbs.) - 42,000; distance: 3'6" Minimum spacing** / 4-Axle Group: weight (lbs.) - 50,000; distance: 3'6" Minimum spacing
Where Alaska allows more than federal limits
- The 38,000 lb. tandem axle limit and 42,000 lb. tridem axle limit exceed the FBF for axle spacing less than 8 feet.
- Alaska does not impose a cap on the gross vehicle weight limit. Gross weight is governed by axle group limits, the FBF, and allowable vehicle configurations.
- During winter months, shifting extra weight (up to 2,000 lbs.) to drive axles within axle groups is allowed, and an overall weight limit tolerance (up to 1,500 lbs.) for ice buildup is provided. State law provides for a 1,000-lb. enforcement tolerance.
Height, width, and length
- Width: 102 inches. States may not set a width limit of more or less than 102 inches on the National Network (23 CFR 658.15(a)). Permits can allow wider loads.
- Height: pending verification. There is no federal height limit; each state sets its own.
- Semitrailer length: pending verification.
- Grandfathered semitrailer length: 48 ft. The minimum semitrailer length the state must allow in a tractor-semitrailer combination on the National Network, based on lengths legal in the state on December 1, 1982. Federal law also requires at least 48 ft (23 CFR 658.13(b)(1)).
Over these limits you need a permit. Alaska oversize/overweight permits (907-365-1200).
Alaska compared with nearby states
| State | Gross | Single | Tandem | Height | Semitrailer |
|---|---|---|---|---|---|
| Alaska | Pending | Pending | Pending | Pending | Pending |
| Washington | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft | 53 ft |
| Oregon | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft | Pending |
| Idaho | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft | 48 ft |
| Montana | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft | 53 ft |
Sources
Source: FHWA, Compilation of Existing State Truck Size and Weight Limit Laws (Report to Congress, May 2015), Appendix B: Summary of State Exceptions to Federal Truck Weight Limits · Effective Oct 1, 2012 · Last verified Sep 28, 2026
Source: FHWA, Compilation of Existing State Truck Size and Weight Limit Laws (Report to Congress, May 2015), Appendix A: Alaska · Effective Oct 1, 2012 · Last verified Sep 28, 2026
Source: 23 CFR 658.15, Width (eCFR) · Last verified Sep 28, 2026
Source: 23 CFR part 658, Appendix B, Grandfathered Semitrailer Lengths (eCFR) · Last verified Sep 28, 2026
Source: FHWA, Oversize/Overweight Load Permits: State permit contacts · Last verified Sep 28, 2026
Limits change, and cities, counties, and posted bridges can set lower ones. Check with Alaska before you run a load near the limits. Page data last verified Sep 28, 2026.