California axle weight limits cap a single axle at 20,000 pounds, a tandem axle group at 34,000 pounds, and total gross vehicle weight at 80,000 pounds on state highways.1Caltrans. Weight Limitation These caps apply to every commercial truck, trailer, and combination vehicle in the state, and California builds no enforcement tolerance into the numbers. One hundred pounds over is over. Fines start at $250 and climb to $2,000, and an officer can force you to offload cargo before you move again.
Weight Limits by Axle Type
California Vehicle Code 35550 sets the foundation. No single axle may impose more than 20,000 pounds on the highway, and no single wheel or set of wheels supporting one end of an axle may exceed 10,500 pounds.1Caltrans. Weight Limitation The statutory cap controls even if your manufacturer’s gross axle weight rating is higher.
A tandem axle group tops out at 34,000 pounds. Under the federal definitions California follows, a tandem consists of two or more consecutive axles whose centers are spaced more than 40 inches apart but not more than 96 inches apart. Axles whose centers fall within 40 inches of each other count as a single axle for weight purposes.2Federal Highway Administration. Bridge Formula Weights That distinction is not academic. Two axles spaced 38 inches apart share a combined 20,000-pound cap, not 34,000.
Front steering axles get their own rule. CVC 35551.5 limits steering axles to 12,500 pounds, but the exemption list is long: dump trucks, buses, tractors pulling semitrailers on a fifth wheel, transit-mix concrete trucks, and tank trucks with at least 1,500-gallon capacity all fall back under the standard 20,000-pound single-axle cap.3Justia. California Code 35550-35558 – Axle Limits Most over-the-road tractors qualify for the exemption. The 12,500-pound limit mostly affects straight trucks and specialty vehicles.
How Axle Group Weights Are Calculated
For groups of two or more consecutive axles, CVC 35551 sets a weight table that ties allowable weight to the distance between the outermost axles.4California Legislative Information. California Vehicle Code VEH 35551 Spread the axles farther, carry more weight. Two axles four feet apart max out at 34,000 pounds. Three axles spread over 20 feet can carry up to 51,000. A five-axle combination spanning 51 feet or more reaches the 80,000-pound gross limit.1Caltrans. Weight Limitation
These state numbers track the Federal Bridge Formula: W = 500 × ((LN / (N − 1)) + 12N + 36), where W is the maximum weight, L is the distance in feet between the outer axles, and N is the number of axles.2Federal Highway Administration. Bridge Formula Weights The formula applies to interior groupings too, not only the outermost axles. An officer can check axles one through three, axles two through five, or any other consecutive set on your vehicle.
Axle spacing is measured to the nearest whole foot. When a measurement lands exactly at six inches, California rounds up.4California Legislative Information. California Vehicle Code VEH 35551 Rounding can bump you into the next row of the weight table, so operators carrying loads near the limit should know their exact spacing.
Zero Tolerance in California
Out-of-state carriers get caught here. California’s statutory weight limits include all enforcement tolerances. CVC 35551(e) says so directly.1Caltrans. Weight Limitation There is no 5% or 10% margin the way some other states allow. If your tandem group weighs 34,100 pounds and the table says 34,000, you are overweight and citable. Scale your loads with less margin than you might elsewhere.
Configuration Rules That Trip Up Operators
Raw weight is only part of the picture. Axle layout matters too.
Spread-axle trailers place two axles farther apart than a standard tandem. Under the Bridge Formula wider spacing can allow more total weight, but the CVC 35551 table still governs, so any advantage only holds where the table actually permits higher weight for that distance.
Lift axles cause more citations than they should. When a trailer is loaded, every lift axle must be fully deployed and carrying its share. Raising a lift axle under load concentrates weight on the axles that stay down, which can push them past the single-axle or tandem cap. Enforcement officers look for this during inspections, and it is easy to spot.
The kingpin-to-rear-axle measurement affects semitrailers. Caltrans restricts this distance to 40 feet for longer semitrailers to limit off-tracking, the tendency of a trailer’s rear wheels to swing wide of the tractor’s path during turns. Exceeding the limit can get you denied access to certain routes or flagged during inspection.
Weight Allowances for Cleaner Trucks
California grants modest weight exemptions for lower-emission commercial vehicles. Under CVC 35551(f), a near-zero-emission or zero-emission vehicle may exceed the weight limits on the power unit by up to 2,000 pounds, to the extent federal law authorizes.5Caltrans. Near-Zero-Emission and Zero-Emission Vehicles The allowance offsets the added weight of batteries and electric drivetrains.
Natural gas vehicles get a narrower calculation. Under 23 U.S.C. 127(s), a truck fueled primarily by natural gas may exceed any weight limit by the difference between its natural gas fuel system and a comparable diesel setup, up to a maximum gross weight of 82,000 pounds.5Caltrans. Near-Zero-Emission and Zero-Emission Vehicles This exemption covers only the fuel system, not the whole power unit.
Trucks equipped with idle reduction technology, such as an auxiliary power unit that runs climate control without idling the main engine, may exceed both the gross vehicle weight limit and axle weight limit by up to 550 pounds.6Alternative Fuels Data Center. Idle Reduction Technology Weight Exemption Drivers claiming this allowance must be able to prove the weight of the unit if asked.
When You Need an Oversize or Overweight Permit
If a load cannot be broken down and exceeds standard weight or size limits, Caltrans can issue a special permit under CVC 35780.7California Department of Transportation. Transportation Permits Manual Chapter 1 The load must be genuinely non-divisible, meaning splitting it would destroy its value or defeat the vehicle’s function. Single-trip permits authorize one movement above 80,000 pounds gross, over 8 feet 6 inches wide, or over 14 feet tall. Annual permits allow repeated movements along designated routes within set dimensions.8Caltrans. Transportation Permits (Oversize/Overweight Vehicles)
Violating any term of a permit is a misdemeanor punishable by up to $500 and up to six months in jail, and if the violation involves excess weight, the CVC 42030 penalty schedule applies on top of the misdemeanor fine, calculated on the amount over what the permit authorized.9California Legislative Information. California Vehicle Code VEH 35784
Fines for Overweight Violations
Fines escalate with the amount of excess weight. CVC 42030.1 sets these tiers for declared gross vehicle weight violations:10California Legislative Information. California Vehicle Code VEH 42030.1
- 1,001 to 1,500 pounds over: $250
- 1,501 to 2,500 pounds over: $300 to $350
- 2,501 to 4,000 pounds over: $400 to $500
- 4,001 to 5,000 pounds over: $550 to $600
- 5,001 to 8,000 pounds over: $700 to $900
- 8,001 to 10,000 pounds over: $1,000
- 10,001 pounds or more over: $2,000
Base fines cannot be partially suspended for repeat offenders. A second or subsequent conviction within three years of a prior violation blocks any reduction.10California Legislative Information. California Vehicle Code VEH 42030.1 Courts add penalty assessments and fees on top of the base amount, which can multiply the total significantly. Once you add offloading, delay, and the possibility of an out-of-service order, a single overweight violation can run several thousand dollars.
Weigh Stations and Enforcement
The California Highway Patrol and Caltrans enforce weight laws through permanent weigh stations, portable scales, and weigh-in-motion sensors embedded in the roadway. Stations sit along major freight corridors including Interstate 5 and Interstate 80. CHP officers can also pull trucks over for random checks based on visual assessment or sensor readings.
Trucks over 10,000 pounds generally must pull into weigh stations along their route unless eligible for a bypass. Bypass eligibility depends on the carrier’s Inspection Selection System score, which combines federal safety metrics. Carriers scoring roughly below 50 on a 100-point scale are more likely to get a bypass signal; those at 75 or above are flagged for mandatory inspection. Any truck can still be called in regardless of score, so a clean record helps but does not guarantee a pass.
When an officer finds a violation, correction happens on the spot. The vehicle may have to offload cargo or redistribute weight before continuing. Officers can issue citations, restrict the vehicle from further travel until it is legal, or in severe cases impound it.