Overweight violations drain profit and damage trust. Many violations start at the dock due to rushed loading, inaccurate weight estimates, or missed reweighs. What seems like simple compliance quickly becomes complicated by axle spacing, state-specific rules, and shifting cargo.
The best way to manage these risks is to verify weight using proper processes, accurate records, and the right tools. This post serves as the ultimate guide to semi-truck weight limits, focusing on accuracy rather than guesswork.
Federal Semi-truck Weight Limits Explained
Federal law sets the baseline for interstate highways. The general gross vehicle weight (GVW) limit sits at 80,000 pounds for a typical five-axle combination under the Federal Bridge Formula. The law also sets a 20,000-pound limit for a single axle and a 34,000-pound limit for a tandem axle group, subject to axle spacing.
Steer axles have their own limits, often determined by tire width and load ratings, which typically keep steer loads between 12,000 and 13,500 pounds. But total weight isn’t the only factor—bridge spacing also matters. The Federal Bridge Formula calculates allowable weight based on the distance between axles, meaning the same 80,000-pound truck can be legal or illegal depending on how its axles are spaced.
State-Specific Truck Weight Limit Variations
Many states follow the federal limits on interstate highways, while others set their own rules for state roads. However, several states adjust single-axle or tandem-axle limits, allow tridem groups without a blanket federal equivalent, or apply different rules on non-interstate roads.
Seasonal restrictions change the picture again. For example, northern states apply frost laws during freeze-thaw cycles to protect pavement, lowering allowable weights or restricting routes. Permit rules also vary by state and load type. Multi-state routes demand planning because one assumption on axle group limits in State A might fail in State B.
Gross Vehicle Weight Rating vs. Legal Weight Limits
Manufacturers assign a gross vehicle weight rating (GVWR) to each truck or trailer based on the design and components. GVWR protects the vehicle and sets a safe mechanical upper limit. DOT agencies enforce legal limits on the road, and those limits operate independently of GVWR.
A tractor-trailer might handle a heavier load mechanically but still exceed legal limits on a given road. Even if the gross vehicle weight stays under 80,000 pounds, a driver can violate steer or tandem axle restrictions. Only verified weights—not manufacturer ratings—determine legal compliance at weigh stations or during roadside inspections.
Axle Weight Limits and Load Distribution
Each axle group plays a distinct role in supporting the truck and trailer. The steer axle controls handling and carries part of the tractor’s weight plus a share of the trailer load. The drive tandem supports the tractor’s rear weight along with much of the trailer’s kingpin load, while the trailer tandem carries the majority of the cargo mass.
Because each axle has a limit, uneven cargo placement can still violate regulations even when the gross weight is legal. Heavy pallets loaded toward the front can overload the steer or drive axles, and liquids that shift during transit increase dynamic loads on different axles mid-trip. Verifying axle weight allows crews to catch these issues early, preventing overloads and avoiding time-consuming rework.
Common Causes of Overweight Violations
Understanding the causes of exceeding weight limits is another key to semi-truck weight limits, as it can help you prevent it from happening. Hard stops, sharp ramps, and uneven road surfaces shift freight forward, increasing the load on the steer or drive axles beyond regulatory limits. Liquid freight intensifies this issue, since sloshing redistributes weight during acceleration and braking, creating momentary axle overloads that trigger violations at inspection points.
Moreover, moisture absorption creates overweight conditions by increasing the total load weight after departure. Aggregates, mulch, and recyclables absorb water during rain or high humidity, pushing gross vehicle weight beyond legal limits without any visible change to the load.
Operational errors create violations in the same way. Last-minute pallet swaps, incorrect material weights, or skipped reweighs remove the only safeguard against unnoticed weight increases.
Consequences of Exceeding Legal Weight Limits
States impose fines that escalate with the number of excess pounds or by tier. Inspectors may place a vehicle out of service until the driver corrects the overload, which delays shipments and creates rehandling costs at the dock or yard.
Excess weight also damages equipment over time. Added stress on suspensions, axles, bearings, and brakes accelerates wear, increases maintenance frequency, and shortens service life across the fleet.
The impact extends beyond a single stop. Overweight citations affect Compliance, Safety, Accountability (CSA) scores and increase scrutiny during future inspections. Likewise, insurance carriers review violation history during renewals and claim investigations, which raises long-term operating risk. Consistent weighing practices reduce exposure across safety, operations, and financial performance.
When and Where To Weigh Trucks
Weigh stations check compliance on public roads, but they operate as spot checks. You gain control when you weigh at the point of loading and before a vehicle exits a private facility. Shipping points, warehouses, recycling yards, and manufacturing sites use on-site scales to verify gross and axle weights before a truck hits the highway.
Facilities with frequent axle distribution issues get strong value from axle-by-axle verification. A simple check at the exit allows quick adjustments via pallet moves or fifth-wheel slides. You improve first-pass success rates at weigh stations and avoid tie-ups that slow the yard.
Truck Scale Types Used To Verify Weight Limits
Full-length truck scales (weighbridges) provide fast gross weight verification for in- and out workflows. Many facilities use them to capture inbound and outbound weights tied to orders, bills of lading, and inventory. You still need axle weights for legal compliance, so many operations pair weighbridges with axle checks when they load mixed freight.
Axle scales provide per-axle and axle-group weights, allowing crews to balance loads before a truck leaves the facility. Portable wheel weighers extend that capability to temporary job sites, seasonal operations, and remote yards where permanent scales are impractical. Onboard weighing systems add another layer of control by displaying live weight data in the cab, using load cells or pressure sensors to help drivers make informed adjustments during loading and staging.
Accuracy, Calibration, and Legal-for-Trade Requirements
Accuracy describes how close a scale reads to a known standard. Environmental factors create drift or error. Debris buildup, temperature swings, out-of-level approaches, wind, vibration, and heavy traffic cycles all push readings off target.
Regular calibration keeps scales within tolerance. Many facilities schedule quarterly or semiannual service based on traffic volume, risk exposure, and state requirements. National Type Evaluation Program (NTEP) certification matters when you bill by weight or need weights that stand up in audits and disputes. State weights-and-measures departments recognize NTEP Certificates of Conformance, so you avoid arguments about the legitimacy of your device and records.
Buy Quality Scales
USA Measurements is a family-owned American brand specializing in industrial weighing and measuring solutions for businesses. We offer a wide range of durable, accurate axle scales that support numerous industries. Take control of every load and protect your operations by prioritizing accurate weighing with the right tools and processes.
