The short version: a Idaho single-trip permit starts at $33 before bands, overweight and the transaction charge; an escort is first required at over 8'6" wide; and the load becomes a superload at over 250,000 lb. Everything below carries the Idaho document it came from, that document's own revision date, and the date we read it.
Corridor
1. Where the load goes next
The jurisdictions this one borders, each chip carrying the fact that decides whether that crossing is the expensive one — so the row is itself a small comparison. A multi-state lane is the actual job, and from here it is one click per state rather than a return to an alphabetical index.
Anything over one of these needs a permit. Every value links to the document that sets it.
Measure
Legal limit
Width
8'6"rev. · read § 49-1010(1): "The width of a vehicle, including any load thereon, except as noted below, shall not exceed eight and one-half (8 1/2) feet." EXCLUSIVE — the section operator is "No vehicle shall exceed the dimensions specified below". One carve-out is recorded and not applied: the same subsection allows a FARM TRACTOR being transported on the interstate system a total outside width of nine (9) feet, "except as permitted by section 49-1004". § 49-1010 also excludes "certain devices determined by the board as necessary for the safe and efficient operation of motor vehicles, including energy conservation devices" from the width calculation, and IDAPA 39.03.01 § 010.03 excludes "front-mounted refrigeration units, energy conservation devices, bolsters, mechanical fastening devices, hydraulic lift gates, external front-mounted side curtain rollers, and other non-cargo carrying appurtenances" from LENGTH.
Height
14'rev. · read § 49-1010(2): "The height of a vehicle, including the load thereon, shall not exceed fourteen (14) feet." EXCLUSIVE, and 14 FT RATHER THAN 13 FT 6 IN — a 13 ft 9 in load needs no Idaho permit, and carrying the 13 ft 6 in figure used elsewhere in this corpus would invent one. Two higher thresholds carry obligations rather than limits: over 16 ft a front height pole (§ 306.02) and a traffic control plan on two-lane highways (§ 300.09), and at 16 ft 6 in or more utility coordination and possible advance notice (§§ 302.02-302.03).
Semitrailer length
53'rev. · read § 49-1010(3)(b)3: "Semitrailers operating on routes which are a part of the national network as set forth in 23 CFR 658, on routes providing access between the national network and terminals and facilities for food, fuel, repairs and rest which are located within one (1) road mile of the national network and state highways as set forth by policy and approved by the transportation board, shall not exceed a length of fifty-three (53) feet." EXCLUSIVE. THE GENERAL LIMIT IS LOWER: § 49-1010(3)(b) caps "a trailer or semitrailer, except as noted in this subsection" at FORTY-EIGHT (48) FEET, and (3)(b)1 caps the OVERALL combination at 65 ft on "routes determined by the board to have severe curvature, deficient width and/or heavy traffic conditions". The 53 ft figure is recorded here because recording 48 ft would flag every ordinary 53 ft trailer in Idaho as over-length; a trailer between 48 and 53 ft that is NOT on the national network, its one-mile access or a board-approved state highway is over-length and is NOT flagged by this row.
Overall length
75'rev. · read § 49-1010(3)(c): "When a motor vehicle and one (1) or more trailers, except as noted in subsection (3)(b), (3)(d) and (3)(e) of this section, the length shall not exceed seventy-five (75) feet." EXCLUSIVE. Corroborated as the operative permit threshold by the ITD Pilot/Escort map, whose first published length band is "Over 75'". Three other combination lengths are recorded and not encoded, because each is confined to a configuration a quote does not state: 65 ft overall on board-designated severe-curvature, deficient-width or heavy-traffic routes (3)(b)1; 61 ft for "a combination of semitrailer and trailer, or of two (2) semitrailers … including the connecting tongue and excluding the truck tractor", rising to 75 ft overall including the tractor once that 61 ft is exceeded (3)(d); 68 ft for the same doubles combination on the national network and its one-mile access (3)(e); and 75 ft for a stinger-steered dromedary tractor with semitrailer (3)(f) and for a dromedary combination carrying class 1 explosives or DoD munitions-related security material (3)(g).
Kingpin to rear axle
None published
Front overhang
None published
Rear overhang
None published
Gross weight
By condition (2)
105,500 lb“noninterstate two lane” or “noninterstate multilane” or “designated 129k route”
20,000 lbrev. · read § 49-1001: "The maximum single axle gross weight shall be twenty thousand (20,000) pounds". IDAHO ALSO CAPS THE SINGLE WHEEL at 10,000 lb in the same sentence, and IDAPA 39.03.01 § 300.07 caps the PERMITTED weight by tyre width: "Maximum Tire Weights. The maximum overweight levels will not exceed eight hundred (800) pounds per inch width of tire." Neither is evaluated, because a quote states no wheel loads and no tyre widths. Note that § 308 publishes HIGHER single-axle figures per route colour — 22,500 lb on yellow routes up to 33,000 lb on black — and those are what a permit AUTHORISES, not what is legal without one.
Tandem axle
34,000 lbrev. · read The federal figure, from § 49-1001(1)'s bridge-formula table: its two-axle rows at "8 and less" through 8 ft all read 34,000 lb. The formula itself is the federal one verbatim — "W=500((LN/N-1)+12N+36) Where W is the maximum weight in pounds (TO THE NEAREST 500 POUNDS)" — which is why no state bridge table is declared. Two Idaho particulars are recorded and not encoded: the table note "WHEN NO ALLOWABLE WEIGHT IS LISTED FOR ANY AXLE SPACING, APPLY THE ALLOWABLE WEIGHT AS LISTED IN THE FIRST COLUMN TO THE LEFT", and § 49-1001(1)(b)'s exception, "Notwithstanding the figures shown in the table in this subsection (1), two (2) consecutive sets of tandem axles may carry a gross load of thirty-four thousand (34,000) pounds each, providing the overall distance between the first and last axles of such consecutive sets of tandem axles is thirty-six (36) feet or more." § 308's route-colour tandem figures (38,000 lb yellow to 56,000 lb black) are permitted levels, not legal limits.
Not one number per dimension — the whole staircase. Each row is a condition the state actually publishes, what it requires when that condition holds, and the clause it comes from. Where a rule requires escorts and the source states no number, the row says that in the source's own words rather than reporting no requirement.
When
What is required
Source
width over 8'6" and Are there sections of the route where this load cannot travel within its proper travel lane? IDAPA 39.03.01 § 306.11 contemplates a front pilot/escort vehicle where there are.
1 in frontAdvisory: IDAPA 39.03.01 § 306.11 is PERMISSIVE, not mandatory: "The movement of an oversize vehicle and/or load MAY be preceded by a pilot/escort vehicle on those sections of highway where the vehicle and/or load cannot travel within its proper travel way lane." ITD sets the actual requirement on the permit face. One front escort is carried here because a load that cannot hold its lane will in practice be escorted, and omitting it would under-quote the largest variable cost on the move.
width over 8'6" and Does the width of this load stop the driver seeing 200 feet behind the vehicle? IDAPA 39.03.01 § 306.12 requires a rear escort when it does.
Escorts required; the source states no number — at least 1. Published as: “IDAPA 39.03.01 § 306.02: "Loads Over Sixteen Feet High. Height poles are necessary in the front of the pilot/escort vehicles leading all loads over sixteen (16') feet high with a non-metallic height pole deployed." EXCLUSIVE ("over sixteen feet"). The subsection assumes escort vehicles lead such a load and states no number, so one is billed as a published floor and the count goes to review. § 302.03 adds an unpriced obligation at a lower height: "Carriers whose load/vehicle combinations exceed sixteen feet six inches (16'6") feet high must contact local utility company(s) for approval and assistance with power lines", and § 302.02 may require advance notice at 16'6" or more where overhead signals are involved.”Height pole required
$33rev. · read IDAPA 39.03.01 § 107.05(b)(i): "Following Permits are thirty-three dollars ($33): i. Overweight/Oversize or Overweight (non-divisible) single trip." (7-1-24). THE SAME SECTION PRICES AN OVERSIZE-ONLY SINGLE TRIP LOWER, at § 107.05(a)(i): "Following Permits are thirty dollars ($30): i. Oversize only, single trip." Idaho prices by PRODUCT, not by dimension, and this field holds one flat amount with no selector for whether the permit involves weight — so the higher published figure is adopted, which never under-quotes, and AN OVERSIZE-ONLY IDAHO MOVE IS THEREFORE QUOTED $3 ABOVE IDAHO'S PUBLISHED $30. Note what § 107.05(b) settles outright: the schedule NAMES the combined over-dimension-and-overweight product and prices it at $33, so the two permit fees are not additive and $30 + $33 has not been assumed anywhere. THE $30/$33 IS THE WHOLE ADMINISTRATIVE CHARGE — § 107.04: "Special permit fees listed below are intended to cover the administration cost and are subject to periodic change depending on costs incurred in processing, issuance, and enforcement of special permit rules." THE $5 ONLINE DISCOUNT DOES NOT APPLY: § 107.06 confines it to annual permits — "ANNUAL special permits purchased online will be five dollars ($5) less than the listed price in Subsection 107.05 of this section." Fees are due at issuance (§ 107.02) and are not refundable once processed unless the permittee contacts Commercial Vehicle Services within two working days of the start date or ITD issued the permit in error (§ 107.03). Tax-supported agencies must obtain permits and are exempt from paying for them. The other published products are not single-trip alternatives and are not applied: nine products at $45 including the annual 129K extra-length/weight permit, $128 for an overweight/oversize (non-divisible) ANNUAL, and $15 to reissue or transfer a permit.
Transaction / card
None publishedrev. · read AN AFFIRMATIVE ABSENCE, AND THE FEE SECTION WAS READ IN FULL (§ 107, subsections 01-07). No service, processing, convenience or percentage charge appears anywhere in it; the permit amounts ARE the administrative charge — § 107.04: "Special permit fees listed below are intended to cover the administration cost". The only transaction-shaped line in the chapter is § 107.05(e), "Reissuance or transfers of a permit is fifteen dollars ($15)", which is a separate event rather than a surcharge on issuance and is not applied. Two open-ended reimbursement powers exist and neither is a published rate: § 107.07 lets ITD "require reimbursement of actual costs incurred for extraordinary services provided, incidental and necessary to the planning and/or movement of loads that require a special permit moving under the requirements of a traffic control plan", and § 102.05 may require insurance plus reimbursement "for any engineering required to ascertain the extent of damages, if any, occurring to the roadway during the movement of the excessive load".
Route analysis review
Not yet covered
Route with no bridges
Not yet covered
Idaho has more than one permit issuer. A state total can be complete and still be missing a whole permit.
Idaho local highway jurisdictions (counties, cities and highway districts) — Any Idaho move that leaves the state highway system. ITD's permit authority stops at the state system in its own words — IDAPA 39.03.01 § 100.03: "The special permit authority of the Department will cover travel on state roadways only, unless the Department has an existing agreement under subsection 004 of this rule… THE RIGHT TO USE COUNTY HIGHWAYS OR CITY STREETS IS NEITHER GRANTED NOR IMPLIED. The special permit authority of the Department will include those sections of state roadways within corporate limits of cities and towns. Still, it will not include sections of state roadways intersecting with local highways, when travel is occurring on the local highway(s)." § 101 lets a jurisdiction fold itself in: "At their discretion, a Local Highway Jurisdiction may enter into an agreement with the Department to allow for the issuance of special permit to include travel on that local jurisdiction controlled highways" — so a local permit ADDS TO the ITD permit unless such an agreement exists, in which case ITD's permit covers it.. We do not hold this authority's fee schedule, so the leg goes to review rather than being quoted short. IDAPA 39.03.01 — Rules Governing Special Permits
Priced by the mile. Idaho Code § 49-1004(2): "Nonreducible vehicles or combinations of vehicles hauling nonreducible loads at weights in excess of those set forth in section 49-1001, Idaho Code, shall pay fees as set forth in this subsection. Such fees are based on the number of axles on the vehicle or combination of vehicles and the total gross weight." The charge is PER MILE and it is NOT per ton-mile — the words "ton" and "ton-mile" do not appear in § 49-1004(2) at all. It is a 4¢-per-mile floor, rising 4¢ per mile for each additional 2,000 lb above an axle-count-specific Column 1 start, resetting to $1.02 per mile at that configuration's Column 2 weight and rising 7¢ per mile per further 2,000 lb, open-ended upward with no published maximum. IDAPA 39.03.01 § 310.01 collects it up front for a single trip: "Mileage and road use fees for single trip special permits are calculated and collected at the time of issuance and are not reported quarterly." THE MILES ARE LADEN IDAHO MILES ON THE PERMITTED ROUTE, AND THE STATE SYSTEM ONLY — § 100.03: "The special permit authority of the Department will cover travel on state roadways only… The right to use county highways or city streets is neither granted nor implied."
Rounding is not a detail here: the same rate over the same miles can differ by a whole increment depending on which pounds are rounded and in which direction, so the rule is printed with the source's own words rather than applied silently.
A permit priced against an unposted-road assumption in March is simply wrong, and wrong in the expensive direction. This is the window we watch, the basis for that window in the state's own orders or statute, and the authority that posts it.
Seasonal posting
Programme
A statewide seasonal programmeIdaho publishes restrictions through the 511 traveller map. There is no bulletin document to cite, so we watch the page and link to it.
Posting window we watch
02-01 → 05-15ITD posts spring break-up restrictions through Idaho 511 as districts thaw; no statutory season is published.
Above one of these, the state stops issuing over the counter and prices the move after an engineering review.
Trigger
Threshold
Gross weight
over 250,000 lbrev. · read IDAPA 39.03.01 § 316.01: "The Department may take up to three (3) business days for an analysis on a vehicle or vehicle combination NOT IN EXCESS OF two hundred fifty thousand (250,000) pounds and up to ten (10) business days for an analysis on a vehicle or vehicle combination OVER two hundred fifty thousand (250,000) pounds. Up to ten (10) business days will also be used for the review process of an analysis done by a third party." The lower branch is INCLUSIVE ("not in excess of") and the upper EXCLUSIVE ("over"), so the threshold fires above 250,000 lb and not at it. NOTE THE ASYMMETRY HONESTLY: Idaho's per-mile ladder is open-ended upward and would still compute above this weight; what stops here is our willingness to quote a move over the counter when the department takes ten business days to analyse it. § 315.01 is the general trigger with no number: "Requests to transport vehicles and/or loads at weights in excess of the weights allowed on a routine basis will require, at a minimum, an additional review and approval from the Department and may require an engineering analysis when structures are involved on the route(s) to be traveled."
Holiday, curfew and night-travel windows are not yet encoded for Idaho. The seasonal picture — which is a different question — is in section 6 above.
Why those windows are absent rather than estimated
They are not guessed at here. What we do publish is the seasonal weight-restriction picture, with the date we last read each state's own bulletin — a curfew invented from a plausible pattern is worth less than an honest gap, because a reader cannot tell the two apart on the page.
Who issues it
11. Permit office
The agency behind each figure above is linked from that figure. We publish no per-state permit-office phone number.
Why there is no phone number here
We are not publishing per-state permit-office phone numbers yet, and the reason is worth stating: the two seed lists available for them are both demonstrably stale — the federal one gives two different states the same phone number — and a wrong number on a page like this costs somebody a morning. The agency behind each figure above is linked from that figure, which is the part we can stand behind today.
Source conflicts
12. Where the sources disagree
Two official documents, both in effect, giving different answers. Neither has been adopted.
legal gross weight
105,500 lbIdaho Code § 49-1001 — Allowable gross loads — PRIMARY, on the legislature's own host. Source of the 105,500 lb non-interstate gross, the 80,000 lb interstate gross, the 20,000 lb single axle, the 10,000 lb single wheel, the 34,000 lb tandem, the federal bridge formula with its "(to the nearest 500 pounds)" rounding and the 36-ft consecutive-tandem exception, and the 105,501-129,000 lb reducible-load band. The page carries its own currency statement: "Idaho Statutes are updated to the website July 1 following the legislative session", so the text read on 2026-10-03 is the law as of 2026-07-01. rev. · read
80,000 lbIdaho Code § 49-1001 — Allowable gross loads — PRIMARY, on the legislature's own host. Source of the 105,500 lb non-interstate gross, the 80,000 lb interstate gross, the 20,000 lb single axle, the 10,000 lb single wheel, the 34,000 lb tandem, the federal bridge formula with its "(to the nearest 500 pounds)" rounding and the 36-ft consecutive-tandem exception, and the 105,501-129,000 lb reducible-load band. The page carries its own currency statement: "Idaho Statutes are updated to the website July 1 following the legislative session", so the text read on 2026-10-03 is the law as of 2026-07-01. rev. · read
Idaho Code § 49-1001 — Allowable gross loads — Idaho State Legislature (Legislative Services Office) — PRIMARY, on the legislature's own host. Source of the 105,500 lb non-interstate gross, the 80,000 lb interstate gross, the 20,000 lb single axle, the 10,000 lb single wheel, the 34,000 lb tandem, the federal bridge formula with its "(to the nearest 500 pounds)" rounding and the 36-ft consecutive-tandem exception, and the 105,501-129,000 lb reducible-load band. The page carries its own currency statement: "Idaho Statutes are updated to the website July 1 following the legislative session", so the text read on 2026-10-03 is the law as of 2026-07-01. rev. · read
Idaho Code § 49-1004 — Special permits for excessive size and weight — Idaho State Legislature (Legislative Services Office) — PRIMARY. Subsection (2) is the whole per-mile road use fee: the Column 1 / Column 2 axle-count table, the 4¢ ladder, the $1.02 Column 2 reset with its 7¢ steps, the 17,000 lb-per-axle extension, the 4¢ floor and the discretionary reduction for wide or multi-tyre axles. Subsection (4) is the annual 129K designated-route permit; subsection (5) its expired $55 cap and the additive registration fees; subsection (1) the local-authority issuing power. Read in full, subsections (1)-(6). History: "am. 2019, ch. 179, sec. 1" and "ch. 180, sec. 1". rev. · read
Idaho Code § 49-1010 — Size of vehicles and loads — Idaho State Legislature (Legislative Services Office) — PRIMARY. Source of the 102 in width, the 14 ft height, the 48/53 ft semitrailer split and the 75 ft combination length. Read in full: it contains no overhang limit and no kingpin-to-rearmost-axle limit. Section operator: "No vehicle shall exceed the dimensions specified below", with each limb reading "shall not exceed" — EXCLUSIVE throughout. rev. · read
IDAPA 39.03.01 — Rules Governing Special Permits — Idaho Transportation Department / Idaho Office of the Administrative Rules Coordinator — PRIMARY, 29 pp., every cited section dated (7-1-24). § 107 (read in full, 01-07) is the fee schedule; § 100.03 and § 101 the state-roadway-only limit and the local-jurisdiction agreement; § 201 the 129K route map; §§ 300-311 the permit conditions, the five-axle overweight qualification, the 800 lb per inch of tyre width cap and the traffic-control-plan thresholds; § 306 (read in full, 01-15) the pilot/escort rules; §§ 315-316 the bridge-approval and analysis gates. THIS CHAPTER REPLACED IDAPA 39.03.21, which was repealed and consolidated into it under Docket No. 39-0301-2301; /rules/current/39/390321.pdf now 404s. rev. · read
ITD — Non-Divisible Oversize or Overweight Permit, Special Permit Attachment — Idaho Transportation Department — PRIMARY IN CONTENT — it reproduces IDAPA 39.03.01 § 104 — SECONDARY HOST (permits4idaho.com, ITD's permit portal). Prints `Rev. 03-26-24`. Source of Idaho's overhang MARKING triggers, which are the reason the overhang LIMIT rows below are absent: "Lights are required when the rear overhang exceeds the end of the trailer by four (4) feet or more to show the maximum width of the overhang." rev. · read
ITD — Pilot/Escort Vehicle Travel Requirements and Vertical Clearance of Structures, Idaho State Highway System — Idaho Transportation Department — PRIMARY IN CONTENT (the map prints its own ITD source path, \\itdhq1fsp07\HQGIS\...\RoutesApproved_PilotEscort_VerticalClearance.mxd) but served from permits4idaho.com, ITD's own permit-ordering portal rather than an itd.idaho.gov URL — SECONDARY HOST. 4 pp., dated January 8, 2025 on the map face. WE HOLD ITS WIDTH AND LENGTH BANDS AND ITS ESCORT VALUES AND NOT THE ROUTE-COLOUR ROWS THAT JOIN THEM: the legend is a map graphic whose text layer returned de-interleaved glyphs under pdftotext -layout and -raw, -bbox-layout exited 99, and no page renderer was available. rev. · read
Common questions
Questions
How much is an oversize permit in Idaho?
The single-trip base is $33, before the dimension bands, the overweight component and the transaction charge. The base alone is rarely what is paid.
When does Idaho require a pilot car?
The first width trigger is over 8'6".
What is a superload in Idaho?
Idaho's published gross-weight superload line is over 250,000 lb. It is not 80,000 lb; that is the federal legal gross limit, not a superload threshold.
Do Idaho's own documents contradict each other?
Yes, in 1 place(s) we hold both documents for. They are set out in full above, each with its pinpoint citation, and none of them has been adopted.