California caps single axles at 20,000 pounds, tandem-axle groups at 34,000 pounds, and gross vehicle weight at 80,000 pounds for most commercial trucks. Those are the headline numbers behind California’s axle weight limits, but the full picture involves per-wheel caps, a sliding scale for axle groups based on spacing, lower thresholds on secondary roads, and fines that climb steeply once a load is more than 5,000 pounds over. Get any of it wrong and the ticket lands on both the driver and whoever loaded or dispatched the truck.
Single-Axle and Per-Wheel Limits
California Vehicle Code 35550 sets the base rule. No single axle may put more than 20,000 pounds on the highway, and no wheel (or set of wheels supporting one end of the axle) may carry more than 10,500 pounds.1California Legislative Information. California Code VEH 35550 – Axle Limits The per-wheel cap is the one that catches operators. A truck can sit under 20,000 pounds on an axle and still be illegal if the load leans hard to one side.
The same statute adds a tire limit. Wheel load cannot exceed the tire manufacturer’s rated load (molded on the sidewall) or 620 pounds per lateral inch of the manufacturer’s rated tire width, whichever is less. For the front steering axle only the manufacturer’s rated limit applies. Livestock loads are exempt from the per-wheel cap but not from the 20,000-pound axle cap.1California Legislative Information. California Code VEH 35550 – Axle Limits
These state limits mirror federal minimums in 23 CFR 658.17, which bar states from enforcing anything lower than 20,000 pounds per single axle or 34,000 pounds per tandem on the Interstate System.2eCFR. 23 CFR 658.17 – Weight
Axle Group Weights and the Bridge Formula
Once two or more axles work together as a group, CVC 35551 takes over. Instead of one fixed number, the statute uses a table keyed to two variables: how many axles are in the group and the distance in feet between the outermost axles. Wider spacing spreads the load over more pavement and bridge deck, so it earns a higher allowance.3California Legislative Information. California Code VEH 35551 – Axle Limits
Tandem Axles
A two-axle group spaced 4 to 8 feet apart tops out at 34,000 pounds. Push the spacing to 9 feet and the allowance climbs to 39,000 pounds.3California Legislative Information. California Code VEH 35551 – Axle Limits Semi-trucks and most heavy commercial rigs run in this range. Even when the tandem group as a whole stays under 34,000 pounds, each individual axle in the group is still bound by the 20,000-pound single-axle rule.
CVC 35551 also contains a specific rule for two consecutive tandem sets: each set may carry 34,000 pounds so long as the distance from the first axle of the first set to the last axle of the second set is 36 feet or more.3California Legislative Information. California Code VEH 35551 – Axle Limits
Tridem and Larger Groups
California does not fix a single tridem number. Three axles at 9 feet of overall spacing can carry 42,500 pounds under the CVC 35551 table; at 12 feet they can carry 45,000.3California Legislative Information. California Code VEH 35551 – Axle Limits The federal Bridge Formula produces close to the same result, with three axles at 97 inches of spacing allowed 42,000 pounds.4Federal Highway Administration. Bridge Formula Weights Heavy-haul construction rigs and specialized freight carriers running tridems should verify the exact spacing on the trailer before assuming an allowance.
The 80,000-Pound Gross Vehicle Weight Cap
Every axle and every group can be legal and the truck can still be over. California enforces a maximum gross vehicle weight of 80,000 pounds for any vehicle combination, matching the federal ceiling in 23 CFR 658.17.5Caltrans. Weight Limitation2eCFR. 23 CFR 658.17 – Weight The Bridge Formula can also drive the allowable gross below 80,000 for particular axle configurations. It never lets you go above.
Lower Limits Off the National Network
Not every California road allows the full 20,000-pound single-axle limit. Under CVC 35551.5, on routes not designated as part of the national network of highways, the single-axle cap drops to 18,000 pounds, the per-wheel cap drops to 9,500 pounds, and the front steering axle is capped at 12,500 pounds.6Justia. California Code VEH 35550-35558 – Axle Limits If a route leaves the interstates and major state highways, check the classification before loading to the higher numbers.
Fines for Overweight Violations
CVC 42030 sets the penalty schedule, and the structure has a hinge point at 5,000 pounds. Under that threshold the fine is a flat amount tied to a weight bracket. Above it, the fine switches to a per-pound rate applied to the entire excess.7California Legislative Information. California Code VEH 42030 – Weight Violations
- 0–1,000 lbs over: $20
- 1,001–1,500 lbs over: $30
- 1,501–2,000 lbs over: $40
- 2,001–2,500 lbs over: $55
- 2,501–3,000 lbs over: $85
- 3,001–3,500 lbs over: $105
- 3,501–4,000 lbs over: $125
- 4,001–4,500 lbs over: $145
- 4,501–5,000 lbs over: $175
- 5,001–6,000 lbs over: $0.04 per pound of total excess
- 6,001–7,000 lbs over: $0.06 per pound
- 7,001–8,000 lbs over: $0.08 per pound
- 8,001–10,000 lbs over: $0.15 per pound
- 10,001+ lbs over: $0.20 per pound
The math moves fast once you cross the hinge. At 5,500 pounds over the base fine is $220. At 9,000 pounds over it is $1,350. At 15,000 pounds over it reaches $3,000. Those are base fines before California’s court-imposed penalty assessments and surcharges, which routinely multiply the base by a factor of four or more.7California Legislative Information. California Code VEH 42030 – Weight Violations
When the Fine Cannot Be Reduced
Courts have no power to reduce or suspend the fine in three situations: when the vehicle owner or employer directed the overweight operation under CVC 40001, when the excess weight is more than 4,000 pounds, or when the driver has a prior weight conviction within the previous three years. Agricultural loads no more than 1,000 pounds over get a narrow exception where the court retains discretion.7California Legislative Information. California Code VEH 42030 – Weight Violations
The Driver Is Not the Only One Cited
CVC 40001 makes it unlawful for a vehicle owner, employer, or anyone else directing a driver to cause or permit operation of a vehicle that violates California’s size and weight rules. The statute creates a rebuttable presumption that anyone who provides a false written certification of actual gross cargo weight has directed the violation.8California Legislative Information. California Code VEH 40001 – Owner Responsibility
In practice, the California Highway Patrol will cite both the driver and the shipper or fleet manager when the evidence supports it, and each is subject to the same CVC 42030 fine schedule. FMCSA has removed size and weight violations from its CSA safety measurement scores, so an overweight ticket does not directly move a carrier’s federal safety rating the way an hours-of-service or maintenance violation would. It still shows up at the roadside, and repeat patterns invite targeted enforcement.
Permits for Non-Divisible Overweight Loads
When a load genuinely cannot be broken into smaller shipments and it exceeds standard limits, Caltrans can issue a special permit authorizing the move on routes under its jurisdiction.9Caltrans. Transportation Permits (Oversize/Overweight Vehicles) Applications require vehicle details, axle configuration, total weight, and the intended route. Some permits cover a single trip; annual permits allow repeated moves within defined parameters. Loads crossing older or structurally sensitive bridges may require a route survey or engineering review.
Federal regulations define a load as non-divisible if separating it would render the vehicle unable to function, destroy or degrade the cargo, or take more than eight hours to dismantle. Construction equipment, industrial machinery, and oversized structural components typically qualify. Divisible cargo like gravel, lumber, or palletized freight does not, and no permit will be issued for a load that could simply ride on two trucks.
The permit itself is only good if you follow it. CVC 35784 makes it unlawful to violate any term or condition of a special permit, and doing so exposes the operator to the same penalties as running overweight with no permit at all.
Emergency Vehicles Follow Different Numbers
The standard California axle weight limits do not apply to qualifying emergency apparatus. Under 23 U.S.C. § 127, states cannot enforce Interstate limits lower than 86,000 pounds gross for emergency vehicles designed to transport personnel and equipment for fire suppression or hazardous-situation response, with a 24,000-pound steering axle allowance and up to 33,500 pounds on a single drive axle.10Office of the Law Revision Counsel. 23 USC 127 – Vehicle Weight Limitations-Interstate System States may also treat these vehicles as carrying non-divisible loads for permit purposes. If the truck in question is a fire engine or rescue vehicle, the 20,000 / 34,000 / 80,000 framework is not the one to plan around.