California limits most commercial trucks to 20,000 pounds on any single axle, 34,000 pounds on a tandem axle group, and 80,000 pounds gross vehicle weight. Those three numbers are the backbone of California’s axle weight limits, but they are not the whole picture: per-wheel caps, tire ratings, axle spacing, and the type of road you’re on can all pull the legal maximum down below what the headline figures suggest.
Single Axle, Per Wheel, and Tire Limits
California Vehicle Code 35550 sets the single-axle ceiling at 20,000 pounds and caps each wheel, or set of wheels supporting one end of an axle, at 10,500 pounds.1California Legislative Information. California Code VEH 35550 – Axle Limits That per-wheel number does real work. A truck can sit under 20,000 pounds on an axle and still be illegal if the load leans to one side.
The same statute ties maximum wheel load to the tire itself. On most axles, the limit is whichever is less: the tire manufacturer’s rated load (molded on the sidewall) or 620 pounds per lateral inch of the manufacturer’s rated tire width. On the front steering axle, only the manufacturer’s rating applies. Livestock loads are exempt from the per-wheel cap but still have to meet the per-axle number.1California Legislative Information. California Code VEH 35550 – Axle Limits
These numbers mirror federal law. 23 CFR 658.17 bars 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 Groups and the Spacing Table
CVC 35551 governs any group of two or more consecutive axles. Instead of one number, the statute uses a table built around two inputs: how many axles are in the group and how many feet separate the outermost axles. Closer spacing means lower allowed weight, because concentrated loads stress bridges and pavement more than spread-out loads do.3California Legislative Information. California Code VEH 35551 – Axle Limits
A two-axle group spaced 4 to 8 feet apart is capped at 34,000 pounds, the familiar tandem number. Stretch that to 9 feet and the allowance rises to 39,000 pounds, climbing further as spacing grows. A three-axle group at 9 feet gets 42,500 pounds; at 12 feet, 45,000 pounds.3California Legislative Information. California Code VEH 35551 – Axle Limits
There is a specific carve-out for two consecutive sets of tandem axles: each set may carry 34,000 pounds provided the distance from the first axle of the forward set to the last axle of the rear set is at least 36 feet.3California Legislative Information. California Code VEH 35551 – Axle Limits One more constraint runs through all of this: no matter what the group table allows, the individual axles inside the group still cannot exceed 20,000 pounds each.
Tandem and Tridem in Practice
Tandems are the common semi-truck setup, and 34,000 pounds is the working number operators memorize for groups spaced under 8 feet 6 inches.4Caltrans. Weight Limitation Tridem configurations (three axles grouped together) show up on heavy-haul construction trucks and specialized freight. The Vehicle Code does not call tridems out separately; you read the allowance off the CVC 35551 table based on the spacing you actually have.
Lower Limits Off the National Network
If your route leaves major interstates and state highways, the ceilings drop. CVC 35551.5 applies tighter caps on roads not designated as part of the national network: 18,000 pounds per single axle, 9,500 pounds per wheel, and 12,500 pounds on the front steering axle.5Justia. California Code VEH 35550-35558 – Axle Limits A load that is clearly legal on I-5 can be over the limit on a secondary road a few miles later.
The 80,000-Pound Gross Cap
Every axle on your truck can be within the legal number and the vehicle can still be overweight. California enforces a maximum gross vehicle weight of 80,000 pounds for any combination.4Caltrans. Weight Limitation This matches the federal ceiling in 23 CFR 658.17, except where the Bridge Formula produces a lower allowed gross for a particular axle layout.2eCFR. 23 CFR 658.17 – Weight The gross cap governs no matter how favorable your spacing numbers look on the table.
What Happens at the Scales
Weigh stations in California are run by the California Highway Patrol. CVC 2813 requires every commercial driver to stop for inspection of size, weight, equipment, and emissions wherever CHP is conducting checks and posting signs that require a stop.6Caltrans. Weigh-Stations (Enforcement Facilities)
At static scales, officers measure individual axle weights and gross weight and review permits, logs, and mechanical condition. Weigh-in-motion sensors screen other trucks at highway speed; vehicles that look clean roll on, and vehicles that look heavy get pulled onto the static scale. If a truck is over, CHP can require the driver to offload cargo on the spot, obtain a special permit, or park the truck until it is compliant, and will usually issue a citation on top.
Fines for Weight Violations
CVC 42030 sets a fine schedule that climbs with the amount of excess weight. For the first 5,000 pounds over, the fine is a flat bracket. Past 5,000 pounds, 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 per-pound jump is steep. At 5,500 pounds over, the base fine is $220. At 9,000 pounds over, it is $1,350. At 15,000 pounds over, $3,000. These are base amounts; California courts add penalty assessments and surcharges that routinely multiply the base by four or more.7California Legislative Information. California Code VEH 42030 – Weight Violations
When the Fine Cannot Be Reduced
Courts lose discretion to reduce or suspend the fine in three situations: when the carrier or vehicle owner directed the overweight operation under CVC 40001, when the excess is more than 4,000 pounds, or when the driver has a prior weight conviction within the past three years. Agricultural loads under 1,000 pounds over get a narrow exception where the court may still adjust the amount.7California Legislative Information. California Code VEH 42030 – Weight Violations
Who Else Gets Cited
The ticket does not stop with the driver. CVC 40001 makes it unlawful for a vehicle owner, employer, or anyone else directing the driver to cause or permit operation of a vehicle that violates California’s size and weight rules. Anyone who provides a false written certification of actual gross cargo weight is presumed to have directed the violation, with the burden on them to rebut it.8California Legislative Information. California Code VEH 40001 – Owner Responsibility In practice, CHP cites the driver and the responsible party when the evidence supports both.
When You Need a Permit Instead
If a load genuinely cannot be legally divided and will exceed standard limits, Caltrans can issue a special permit for the move. Caltrans has discretion under the Vehicle Code to permit oversize or overweight vehicles on highways under its jurisdiction when good cause is shown.9Caltrans. Transportation Permits (Oversize/Overweight Vehicles)
The application identifies the vehicle, axle configuration, total weight, and intended route. Caltrans weighs whether the load can move without excessive damage to pavement or bridges. Single-trip permits cover one move; annual permits cover repeated moves inside set parameters. Routes crossing older or structurally sensitive bridges may require a route survey or engineering review.
Federal rules define a load as non-divisible if separating it would make the vehicle unable to perform its function, destroy or degrade the cargo, or take more than eight hours to dismantle. Construction equipment, industrial machinery, and oversized structural components typically qualify; gravel, lumber, and palletized freight do not, and no permit will be issued for a load that could simply be split across two trucks.
A permit is not a pass to ignore its own terms. CVC 35784 makes it unlawful to violate any condition in a special permit, and the penalties track those for operating overweight with no permit at all.