Colorado truck weight limits
On Interstate highways in Colorado, federal weight limits apply. Four checks decide whether your truck is legal — and the one that surprises most drivers is the Federal Bridge Formula, which can fail a truck that passes every other limit.
Federal limits on Colorado Interstates
| Limit | Maximum | Applies to |
|---|---|---|
| Single axle | 20,000 lb | Any one axle |
| Tandem axle group | 34,000 lb | Axles 40–96 inches apart |
| Tridem axle group | governed by the bridge formula | 3 axles in a group (no flat federal cap) |
| Gross vehicle weight | 80,000 lb | The whole rig |
| Bridge formula | varies by spacing | Every group of 2+ axles |
The bridge formula check
L is the spacing in feet between the outer axles of a group, N the number of axles. A standard 5-axle rig at 51 ft is capped at 79,500 lb by this formula — under the 80,000 lb gross limit. Full explanation with worked examples.
Colorado-specific rules
Colorado is one of the Western states that lets you run heavier than 80,000 lb off the Interstate. On the Interstate, federal limits govern: 20,000 lb single axle, 34,000 lb tandem, 80,000 lb gross, plus the Federal Bridge Formula. On non-Interstate highways, Colorado uses its own numbers (C.R.S. §§ 42-4-507 & 508): a 40,000 lb tandem (versus the federal 34,000) and a gross-weight formula, W = 1,000 × (L + 40), that allows up to 85,000 lb. Colorado also runs fixed Ports of Entry where trucks are weighed, and its mountain corridors carry route-specific restrictions.
Colorado exceptions to the federal limits
Colorado's limits (C.R.S. §§ 42-4-507 & 508):
| Group | Interstate | Non-Interstate |
|---|---|---|
| Single axle | 20,000 lb | 20,000 lb |
| Tandem axle group | 34,000 lb | 40,000 lb |
| Maximum gross | 80,000 lb (bridge formula) | 85,000 lb (W = 1,000 × (L + 40)) |
- Off the Interstate, gross is set by W = 1,000 × (L + 40) where L is the feet between the extreme axles — capped at 85,000 lb.
- On Interstates, federal limits govern — 20,000 / 34,000 / 80,000 plus the bridge formula; the 40,000 lb tandem and 85,000 lb gross do not apply there.
Seasonal & designated-route rules in Colorado
Colorado does not run a statewide spring "frost law" weight program. The constraints that bite here are mountain-corridor route restrictions (chain laws and route-specific limits on I-70 and mountain passes) and posted-bridge weight limits. Winter traction/chain requirements can close routes to heavy loads outright — check CDOT's current corridor status and posted limits before committing a load over the passes.
Overweight permits in Colorado
Loads over the legal limits need an oversize/overweight permit from CDOT (single-trip or annual), route-specific by bridge and pavement rating. Mountain corridors and posted structures may be excluded regardless of permit.
Fines & enforcement in Colorado
Enforced by the Colorado State Patrol at fixed Ports of Entry and with portable/mobile enforcement. Overweight violations carry graduated per-pound penalties; loads can be held until brought within limits.
What dispatchers should check in Colorado
- Interstate vs. non-Interstate — off the Interstate Colorado allows a 40,000 lb tandem and up to 85,000 lb gross; on the Interstate you're back to the federal 34,000 / 80,000.
- The gross formula — non-Interstate gross is W = 1,000 × (L + 40), capped at 85,000 lb; more spacing buys more weight up to the cap.
- Mountain corridors — check CDOT chain laws and route restrictions on I-70 and the passes.
- Ports of Entry — Colorado weighs at fixed ports; plan to be legal through them.
Colorado truck weight — frequently asked questions
How much can a truck weigh in Colorado?
On Colorado Interstates the federal gross-weight limit is 80,000 lb, with a 20,000 lb single-axle limit, a 34,000 lb tandem limit and the Federal Bridge Formula. Colorado sets its own limits on non-Interstate roads — see the Colorado-specific rules on this page.
Does Colorado follow federal truck weight limits?
On the Interstate system, yes — federal limits govern in every state. Off the Interstate, Colorado applies its own axle, gross and permit rules, detailed on this page where they have been verified against the official state source.
What is the single-axle weight limit in Colorado?
The federal single-axle limit of 20,000 lb applies on Colorado Interstates. Some states set a different single-axle figure on non-Interstate roads — check the Colorado-specific section above for the governing number.
What is the maximum tandem-axle weight in Colorado?
On Colorado Interstates the federal tandem limit is 34,000 lb. Several states allow a different tandem weight on non-Interstate roads — see the Colorado exceptions above for the figure that governs.
Scaled heavy in Colorado?
If the trailer tandems are over, the fix is usually a computed tandem slide, not unloading — see how sliding tandems shifts weight. And here's what an overweight ticket really costs before you decide to run it.
Run your scale-ticket weights through the federal and bridge-formula calculator in your browser. The full platform predicts axle loads from load placement before you load, computes the exact slide-to-legal fix, and applies Colorado rules on top of the federal baseline.
Open the free calculatorOur calculator runs the federal single, tandem, gross and Bridge Formula checks in seconds. The full platform adds per-state limits, axle-load prediction and the slide-to-legal fix.
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