Steel beams for a building can run longer than the trailer carrying them. Say 75-foot beams on a 53-foot flatbed, headed across California. For length, they usually need no permit. California’s Vehicle Code lets structural loads up to 80 feet, such as beams, poles, pipes and other one-piece loads, travel without one, and Caltrans won’t issue one for a load that qualifies. The exemption has edges, though, and a load that crosses one needs a permit like any other.
The short version
Structural loads up to 80 feet long, steel beams among them, need no length permit in California. Under Vehicle Code §35414, a truck carrying only poles, timbers, pipes, integral structural materials or one-piece parts up to 80 feet is free of the state’s length limits, on a pole dolly or a semitrailer, and Caltrans’s Transportation Permits Manual counts steel beams for building construction among them. Caltrans issues no permit for a load that qualifies, and that includes a stretch trailer when the beam needs its support. Width, height and weight must stay legal, and on a semitrailer the tail can’t pass two-thirds of the wheelbase. A load over 80 feet needs a Caltrans permit, which Permigo files. Permigo read the code, Caltrans’s manual and the California Highway Patrol’s on October 13, 2026.
What Vehicle Code §35414 says
The exemption is Vehicle Code §35414. If a truck hauls nothing but poles, timbers, pipes, structural materials or one-piece parts no longer than 80 feet, the code’s length limits don’t apply. The statute lists the loads as “poles, timbers, pipes, integral structural materials, or single unit component parts, including, but not limited to, missile components, aircraft assemblies, drilling equipment, and tanks not exceeding 80 feet in length.” Caltrans’s Transportation Permits Manual adds the load most of these questions are about: “Steel beams used in building construction fall into this category.”
| Load | Covered? | Where it says so |
|---|---|---|
| Steel beams for building construction, up to 80 feet | Yes | Permits Manual §201.52 |
| Poles, timbers and pipes, up to 80 feet | Yes | Vehicle Code §35414 |
| Laminated wood beams, up to 80 feet | Yes, and Caltrans says they “must be hauled legal” | Permits Manual §201.27 |
| One-piece parts such as tanks, drilling equipment or aircraft assemblies, up to 80 feet | Yes | Vehicle Code §35414 |
| Shorter pieces loaded end to end | No | Highway Patrol manual, p. 8-20 |
| A load that could travel within the normal length limits | No. Haul it legal | Vehicle Code §35414; Permits Manual §201.26 |
| Beams with other freight on the same truck | No. The code covers a truck carrying “only” these loads | Vehicle Code §35414 |
It’s only for loads that can’t go legal. Caltrans adds a test: a load that can ride within the legal overhang without “structural damage being caused by flexing” isn’t covered.
What the 80 feet measures
Only the load. Caltrans’s steel-beam entry says the length “does not include the draw bar or tractor.” The California Highway Patrol’s size and weight enforcement manual reads the code the same way. With a qualifying load, it says, the overall length of the combination “is unlimited,” and the 75-foot load limit in §35411 doesn’t apply.
So a 75-foot beam is fine at 75 feet, even though the truck in front of it makes the whole rig well over 75 feet. An 81-foot beam is not, however short the rig.
Which trailers it covers
The statute names three setups:
- A pole or pipe dolly, or another lawful trailer used as one, behind a motor vehicle. A pole dolly is tied to the truck by chain, cable or drawbar and by the load itself, and none of its weight rests on the truck (Vehicle Code §475).
- A semitrailer, “except for the limitations provided in Section 35410”: the rear overhang rule below.
- A semitrailer and a pole or pipe dolly behind a truck tractor, for flexible integral structural material.
Utilities get a carve-out of their own. An electric or telephone utility, a local agency in that business, Caltrans, or a licensed contractor working for one of them may move up to three poles of 80 feet or less, with the job’s tools and materials, between a storage yard and a job site. The poles ride on a pole or pipe dolly, or on a semitrailer used as one.
On a pole dolly, the Highway Patrol doesn’t apply the two-thirds rule below, because the load rests on both vehicles. On a semitrailer it applies, and it’s usually the first limit a beam load meets.
California’s legal rear overhang limit: two rules
California’s rear overhang law sets two limits, and how much tail each allows depends on the rig. Caltrans’s overhang page lists them side by side.
- Two-thirds of the wheelbase (§35410). A load can hang past its last point of support by no more than two-thirds of the wheelbase of the vehicle carrying it. On a semitrailer, the wheelbase runs from the tractor’s rearmost axle to the trailer’s rearmost axle. The last point of support is the rearmost point of the deck holding the load; the Highway Patrol doesn’t count braces angled out to stretch it.
- 75 feet for the load on a combination (§35411), measured from the front of the rig to the end of the load. On a combination the code lets run longer than 75 feet, such as a STAA tractor and trailer, nothing may hang past the vehicles.
For a qualifying load, the Highway Patrol’s manual says the 75-foot rule doesn’t apply. On a semitrailer, the two-thirds rule still does.
An example, on an invented rig. Say the tractor’s rear axle sits 39 feet ahead of the trailer’s rear axle. Two-thirds of 39 feet is 26 feet. Load 75-foot beams flush with the front of a 53-foot deck and they hang 22 feet past it, inside 26 feet, so the overhang is legal. Without §35414 the same load would break §35411, because the beams alone are 75 feet and the tractor sits ahead of them. With it, the load moves without a length permit. The flags and lights below still apply.
On the same rig, an 80-foot beam would hang 27 feet past the deck, a foot over the limit. The longest beam it can carry that way is 79 feet. A longer wheelbase allows a longer tail.
You may hear 25 feet called California’s limit. It’s a different rule. On a permitted load, Caltrans wants a pilot car behind any rear projection over 25 feet (Permits Manual §502.6), and the pilot car guide has California’s other escort rules. Permigo’s limits check shows the two rules above under its overhang row. It can’t test them, since it doesn’t ask for the wheelbase.
Does a stretch trailer need a permit?
No, not for length. A stretch trailer carrying a steel beam up to 80 feet falls under the same rule, §35414, so it needs no permit. Caltrans’s Transportation Permits Manual gives the same case with a long pipe: when the pipe needs the stretch trailer’s support, the move is covered by §35414.
Two things must be true:
- The beam needs the longer trailer. If it could ride on a normal 53-foot trailer, Caltrans says to use the normal trailer.
- The trailer is legal when collapsed: 53 feet or shorter, with no more than 40 feet from the kingpin to the rear axle. If it’s longer than that even collapsed, Caltrans wants a permit, and Permigo files it.
Everything else still applies: legal width, height and weight, a tail no longer than two-thirds of the wheelbase, and flags and lights.
Example: a 76-foot steel beam. You extend the trailer so the beam is supported. The beam is under 80 feet, the load is legal width, height and weight, and the trailer is legal when collapsed. You need no permit. On the way back empty, collapse the trailer to its legal length, because the rule only covers a loaded trailer.
When the exemption doesn’t apply
| When | What happens | Where it says so |
|---|---|---|
| Beams over 80 feet | A single-trip permit while the rig and load together stay within 135 feet, with a written reason the beam can’t be made shorter. Past 135 feet, a variance permit | Permits Manual §201.52 |
| Wider than 8 feet 6 inches or taller than 14 feet | A permit for the width or height. Caltrans’s steel-beam permit goes up to 12 feet wide, at legal height | Vehicle Code §35100, §35250; Permits Manual §201.52 |
| Over legal weight | Not covered. The load moves on a permit | Permits Manual §201.26, Example 2 |
| On a semitrailer, a tail longer than two-thirds of the wheelbase | Not covered | Vehicle Code §35414, §35410 |
| A stretch trailer (one that extends for a longer load) | Covered when the load needs the trailer’s support. A permit when the trailer is over 40 feet from kingpin to rear axle even collapsed | Permits Manual §201.26, Examples 1 and 3 |
| The trip back empty | Not covered: the exemption is for a loaded rig. A trailer over the legal limits even when empty may qualify for a single-trip permit on its way to or from a load that needs it | Highway Patrol manual, p. 8-20; Permits Manual §111 |
The two manuals part ways on one case: a stretch trailer over 40 feet from kingpin to rear axle even collapsed. The Highway Patrol’s says that measure “is not an applicable measurement” for these loads. Caltrans’s example treats such a trailer as needing a permit even with a qualifying load. Where they differ, the permit is the safe side. A stretch trailer also gets a permit when a beam over 80 feet would be damaged by hanging out (Permits Manual §307.2).
Two questions none of these sources settles: whether a city or county length ordinance can still bind a load §35414 covers, and whether Caltrans’s long-load signs apply to a move with no permit. Ask the city, county or Caltrans before a borderline move.
Flags and lights still apply
The exemption covers length only. The flag and light rule, §24604, is in another part of the code. It applies once a load hangs 4 feet or more past the rear, measured from the taillamps:
- by day, a solid red or fluorescent orange flag or cloth at least 18 inches square at the end of the load, or two if the part that hangs out is wider than 2 feet;
- in darkness, two red lights at the end, visible from 500 feet to the sides and rear, besides the taillamp.
Where Permigo comes in
Caltrans won’t issue an overlength permit for a load §35414 covers, so not every long load is a filing. Send Permigo the load: what it is, how long, the trailer and the tail, the width, height and weights, and the route. If the exemption covers it, Permigo tells you so from those details and charges nothing. If it doesn’t, Permigo files the Caltrans permit for $20, with Caltrans’s own fee billed at cost. That’s the case for beams over 80 feet, for a load too wide, too tall or too heavy, and for a stretch trailer or an empty leg that needs a permit.
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Who to call
Permigo checked the contact details below on October 13, 2026.
| Question | Who answers it |
|---|---|
| Questions for Caltrans about a California permit | Caltrans Oversize/Overweight Permits Office: (916) 322-1297, 8:00 a.m. to 5:00 p.m. Pacific, Monday to Friday, closed on state holidays |
| California’s other permit and escort rules | The California page |
| Whether a load qualifies, and filing the permit when it doesn’t | Permigo: +1 (786) 494-6912, 7am–7pm CT, seven days a week, or send a message |
Common questions
Do structural loads up to 80 feet need an overlength permit in California?
Not for length. Under Vehicle Code §35414, a truck carrying only poles, timbers, pipes, integral structural materials or one-piece parts up to 80 feet long is free of California’s length limits, on a pole dolly or a semitrailer, and Caltrans counts steel beams for building construction among them. Caltrans issues no permit for a load that qualifies. The 80 feet counts the load only. Width (8 feet 6 inches), height (14 feet) and weight must stay legal, and on a semitrailer the tail can’t pass two-thirds of the wheelbase. Permigo read the code and Caltrans’s Transportation Permits Manual on October 13, 2026.
What is California’s legal rear overhang limit?
Two rules cap it. The load can hang past its last point of support by no more than two-thirds of the wheelbase of the vehicle carrying it (Vehicle Code §35410); the Highway Patrol doesn’t apply this when the load rests on two vehicles, as on a pole dolly. And on a combination, the front of the rig to the end of the load can’t pass 75 feet; on a combination the code lets run longer than 75 feet, such as a STAA tractor and trailer, nothing may hang past the vehicles (§35411). 25 feet is a different rule: Caltrans wants a pilot car behind a permitted load past it. Permigo read the code on October 13, 2026.
How do you calculate rear overhang in California?
Measure from the last point of support, the rearmost point of the deck holding the load, to the end of the load. Then compare it with two-thirds of the wheelbase. On a semitrailer, California counts the wheelbase from the tractor’s rearmost axle to the trailer’s rearmost axle (Vehicle Code §35410). On an example rig with 39 feet between those axles, two-thirds is 26 feet, so a 22-foot tail is legal and a 27-foot tail is not. The Highway Patrol doesn’t count braces angled out to stretch the last point of support.
What if the steel beams are longer than 80 feet?
Then §35414 doesn’t cover them, and the load needs a Caltrans permit. Under Caltrans’s Transportation Permits Manual, steel beams over 80 feet get a single-trip permit while the rig and load together stay within 135 feet, with a written reason the beam can’t be made shorter. Past 135 feet, it’s a variance permit. Permigo files the permit. Permigo read the manual on October 13, 2026.
Does a stretch trailer need a permit in California?
Not for length. A stretch trailer carrying a steel beam up to 80 feet falls under the same rule, Vehicle Code §35414, so it needs no permit, as long as two things are true: the beam needs the longer trailer to support it, and the trailer is legal when collapsed (53 feet or shorter, with no more than 40 feet from the kingpin to the rear axle). Caltrans’s Transportation Permits Manual gives the same case with a long pipe. On the trip back empty, the rule no longer covers you, so collapse the trailer to its legal length. Permigo read the manual on October 13, 2026.
Do I need flags or lights on a long load in California?
Yes, once the load reaches 4 feet or more past the rear, measured from the taillamps (Vehicle Code §24604). By day, a solid red or fluorescent orange flag or cloth at least 18 inches square at the end, or two if the part that hangs out is wider than 2 feet. In darkness, two red lights visible from 500 feet. The §35414 exemption doesn’t lift this rule. Permigo read the code on October 13, 2026.
How much does a California oversize permit cost?
If §35414 covers the load, there’s no overlength permit to buy: Caltrans issues none. A load over legal width, height or weight still needs one. Caltrans’s fee is in Permigo’s cost guide, and Permigo’s fee to file the permit is $20, with Caltrans’s fee billed at cost. From the load details you send, Permigo also tells you, free, whether a long load qualifies.
Who do I contact about a long load in California?
The Caltrans Oversize/Overweight Permits Office in Sacramento: (916) 322-1297, 8:00 a.m. to 5:00 p.m. Pacific, Monday to Friday, closed on state holidays (Caltrans’s contact page, checked October 13, 2026). Permigo answers at +1 (786) 494-6912, 7am–7pm CT, seven days a week, says whether a load qualifies and files the permit when it doesn’t. California’s other rules are on Permigo’s California page.