ID
Idaho oversize permit rules
What Idaho charges for a single-trip OS/OW permit, the limits that trigger one, and the escort thresholds — read from the state’s own publication. This rule has been in effect since 2026-07-10; we last read the source on 2026-07-10.
Oversize permit
$30
One price for a single-trip permit, whatever the dimensions. A 9-foot-wide load and a 16-foot-wide load pay the same.
Overweight permit
Quoted per load
Scales with axle count — there is no single figure.
A load that is both oversize and overweight pays this fee only, not both.
+ $20 Permigo service fee per permit, state fees at cost.
Legal limits
Exceed any one of these in Idaho and you need a permit for this state.
| Limit | Interstate | Off-interstate |
|---|---|---|
| Width | 8'6" | 8'6" |
| Height | 14'0" | 14'0" |
| Length | 75'0" | 75'0" |
| Gross weight | 80,000 lbs | 105,500 lbs |
| Single axle | 20,000 lbs | |
| Tandem axle | 34,000 lbs | |
| Trailer length | 53'0" |
What the permit costs
Idaho prices a single-trip permit as flat rate. One price for a single-trip permit, whatever the dimensions. A 9-foot-wide load and a 16-foot-wide load pay the same.
Escort requirements
Thresholds by road class. Where two classes differ, the road you are actually on governs.
Interstate (White)
| Width | Requirement |
|---|---|
| Over 13'0" | Not permittedCOMMUTER CURFEWS: loads over 13' wide are barred 6:00–9:00 a.m. and 4:00–6:30 p.m. Mon–Fri (right lane only during those hours) on listed corridors: Boise I-84 MP 26–59, Coeur d'Alene I-90 MP 0–17, Idaho Falls I-15 MP 115–121, Pocatello I-15/I-86/US-30/US-91, Twin Falls US-93 MP 41–53, + Eagle/Emmett/Garden City/Middleton/Star routes (IDAPA 39.03.01.305.08–.09). |
| Over 15'0" | 1 rear escortInterstate (White) routes: over 15' to 18' wide = 1 REAR pilot (the official Jan-2025 map — the old grid's front+rear-over-16' band belonged to BLACK routes; interstates stay 1 rear through 18'). |
| Over 18'0" | superload permitOver 18' wide on the Interstate: additional Department approval required — up to 24 working hours (IDAPA 39.03.01.305.11.b). A traffic-control plan (engineer/ATSSA-prepared) attaches on 2-lane segments over 18'W/150'L/16'H (§300.09). |
| Height | Requirement |
|---|---|
| Over 16'0" | 1 front escort · height pole · superloadOver 16'0" high: a non-metallic height pole deployed on the FRONT pilot leading the load (§306.02 — one vehicle; the old 16'1" trigger was off by an inch) AND Department approval on any route (§305.11.c). At 16'6"+: advance notice for overhead signals and MANDATORY utility contact for power lines (§302.02–.03). Structures under 16' clearance are posted on the map (yellow ≤14' / blue 14'1"–15' / green 15'1"–15'6"). |
| Length | Requirement |
|---|---|
| Over 120'0" | Travel window appliesOver 120' on the Interstate: NO map-mandated length escort (the White row has no length cells) — but the load loses 24/7 eligibility (daylight only). Department approval starts at >150' on the Interstate (§305.11.e; the non-interstate threshold is 120'). |
| Over 150'0" | superload permitOver 150' on the Interstate: additional Department approval — up to 24 working hours (§305.11.e). |
| Front overhang | Requirement |
|---|---|
| Over 7'0" | Travel window appliesFront overhang over 7': DAYLIGHT ONLY on 2-lane highways (§305.07). Rear overhang over 4': extremity lights + 18"×18" flags (one if the overhang is ≤2' wide, two if wider — §104). |
| Rear overhang | Requirement |
|---|---|
| Over 4'0" | Marking requiredRear overhang over 4': lights + flags per §104. NO fixed rear-overhang escort exists (the old >25' rear-escort band was a) |
| Weight | Requirement |
|---|---|
| Over 250,000 lbs | route surveyOver 250,000 lb: bridge analysis up to 10 business days (≤250k runs 3; §316.01). Steer/single axle over 35,000 lb needs bridge approval regardless (§315.02). |
| 800,000 lbs and over | Conditions apply800,000 lb and over: THIRD-PARTY bridge analysis mandatory at the applicant's expense, ITD reviews up to 10 business days (§316.02). Multi-configuration or multi-route requests also go third-party (§316.04–.05). US-12 MP 74–174 (Nez Perce–Clearwater): loads >16'W / >150,000 lb / >150'L or >12-hr transit trigger the federal-court megaload regime — USFS review, ISP vehicle inspection before issuance, one-load-at-a-time monitoring (§307). |
2-lane (Black-map basis)
| Width | Requirement |
|---|---|
| Over 12'0" | 1 front escortBLACK-coded routes (the general non-interstate scheme, our billing basis): over 12' wide = 1 FRONT pilot (Jan-2025 map).RED-CODED corridors (RARE — just eight short canyon/lake-shore segments statewide, read off the Jan-2025 map): SR-21 Boise–Idaho City–Lowman (MP 17.16–72.6) · SR-55 Payette River Canyon, Horseshoe Bend–Smiths Ferry (MP 78.8–101.54) · SR-55 McCall–New Meadows (MP 143–156) · SR-75 Salmon River Canyon east of Stanley (MP 189.3–209.14) · SR-36 Preston–Montpelier, Emigration Canyon (MP 0–33.9) · SR-97 Lake Coeur d'Alene east shore, Harrison north (MP 66–96.3) · SR-200 Clark Fork–Montana line (MP 55.5–63) · SR-71 Brownlee/Hells Canyon approach (MP 0–7). On these: 1 FRONT pilot from over 8'6" wide, FRONT+REAR over 10', length pilot from over 75'; weekends and holidays BANNED, travel stops Friday/holiday-eve 2 p.m., resumes at dawn Monday/after. Everything else on the state system is BLACK (the thresholds we bill). |
| Over 13'0" | Not permittedCOMMUTER CURFEWS: loads over 13' wide are barred 6:00–9:00 a.m. and 4:00–6:30 p.m. Mon–Fri (right lane only during those hours) on listed corridors: Boise I-84 MP 26–59, Coeur d'Alene I-90 MP 0–17, Idaho Falls I-15 MP 115–121, Pocatello I-15/I-86/US-30/US-91, Twin Falls US-93 MP 41–53, + Eagle/Emmett/Garden City/Middleton/Star routes (IDAPA 39.03.01.305.08–.09). |
| Over 14'0" | 1 front escort + 1 rear escortBlack routes: over 14' to 18' wide = FRONT + REAR pilots |
| Over 16'0" | superload permitOver 16' wide on red- or black-coded routes: additional Department approval — up to 24 working hours (§305.11.a). |
| Height | Requirement |
|---|---|
| Over 16'0" | 1 front escort · height pole · superloadOver 16'0" high: height pole on the FRONT pilot (one vehicle, §306.02) + Department approval on any route (§305.11.c). 16'6"+ adds signal notice + mandatory utility contact (§302.02–.03). |
| Length | Requirement |
|---|---|
| Over 120'0" | 1 front escort · superloadBlack routes: over 120' = 1 FRONT pilot AND Department approval (non-interstate threshold, §305.11.d). RED routes: the length pilot starts at >75' (route-dependent — see the red-corridor alert).RED-CODED corridors (RARE — just eight short canyon/lake-shore segments statewide, read off the Jan-2025 map): SR-21 Boise–Idaho City–Lowman (MP 17.16–72.6) · SR-55 Payette River Canyon, Horseshoe Bend–Smiths Ferry (MP 78.8–101.54) · SR-55 McCall–New Meadows (MP 143–156) · SR-75 Salmon River Canyon east of Stanley (MP 189.3–209.14) · SR-36 Preston–Montpelier, Emigration Canyon (MP 0–33.9) · SR-97 Lake Coeur d'Alene east shore, Harrison north (MP 66–96.3) · SR-200 Clark Fork–Montana line (MP 55.5–63) · SR-71 Brownlee/Hells Canyon approach (MP 0–7). On these: 1 FRONT pilot from over 8'6" wide, FRONT+REAR over 10', length pilot from over 75'; weekends and holidays BANNED, travel stops Friday/holiday-eve 2 p.m., resumes at dawn Monday/after. Everything else on the state system is BLACK (the thresholds we bill). |
| Front overhang | Requirement |
|---|---|
| Over 7'0" | Travel window appliesFront overhang over 7': DAYLIGHT ONLY on 2-lane highways (§305.07). Rear overhang over 4': extremity lights + 18"×18" flags (§104). |
| Rear overhang | Requirement |
|---|---|
| Over 4'0" | Marking requiredRear overhang over 4': lights + flags per §104. NO fixed rear-overhang escort exists (the old >25' band was a) |
| Weight | Requirement |
|---|---|
| Over 250,000 lbs | route surveyOver 250,000 lb: bridge analysis up to 10 business days (≤250k runs 3; §316.01). Steer/single axle over 35,000 lb needs bridge approval regardless (§315.02). |
| 800,000 lbs and over | Conditions apply800,000 lb and over: THIRD-PARTY bridge analysis mandatory (§316.02). US-12 MP 74–174 megaload regime for >16'W / >150k / >150' / >12-hr moves (§307). |
Movement restrictions
| Restriction | In Idaho |
|---|---|
| Night travel | Night travel allowed |
| Weekends | No blanket restriction |
| Holidays | Restricted |
ITD pilot/escort map — the official grid (January 8, 2025 edition)
| Route class | Width — 1 pilot | Width — front + rear | Length — pilot | Weekends / holidays |
|---|---|---|---|---|
| <span class="cdot" style="--c:#C25454"></span><b>Red</b> (restrictive 2-lane) | >8′6″ (front) | >10′ | >75′ (front) | BANNED · Fri 2 p.m. stop |
| <span class="cdot" style="--c:#4A4A45"></span><b>Black</b> (general) | >12′ (front) | >14′ | >120′ (front) | OK · 24/7 ≤12′W×120′L×15′H |
| <b>White</b> (Interstate) | >15′ (rear) | — (to 18′) | — (none) | OK · 24/7 ≤12′W×120′L×15′H |
Movement hours (IDAPA 39.03.01.305 + the Jan-2025 pilot map, verified 2026-07-10)
| Load | Window |
|---|---|
| Black & Interstate routes — within 12′W × 15′H × 120′L | 24/7, 7 days (night extremity lighting) |
| Larger loads (black/interstate) | daylight only; stop 4 p.m. the day before a holiday; >12′ wide: no movement on the 6 holidays |
| RED routes | daylight only; travel stops FRIDAY 2 p.m. (or 2 p.m. pre-holiday); NO weekends, NO holidays; resume sunrise Monday |
| Commuter curfews (>13′ wide) | 6–9 a.m./4–6:30 p.m. M–F: Boise I-84, CdA I-90, Idaho Falls I-15, Pocatello, Twin Falls corridors |
| 6 holidays (§305.04) | New Year's, Memorial, Independence, Labor, Thanksgiving, Christmas (the old 3-day holiday-weekend rule is GONE) |
| Weather auto-invalidation (§102.06) | wind >40 mph, visibility <500′, ice/traction loss, or a '511-Difficult' marking VOIDS the permit en route |
Where these permits come from
If you file yourself, this is the office you are dealing with. Check the linked page — some states issue OS/OW permits through their highway patrol or revenue department rather than the DOT.
| Idaho permit office | |
|---|---|
| Permit office | (208) 872-3163 |
| [email protected] | |
| Permit portal | permits4idaho.com (ITRPS — Idaho Transportation Routing and Permitting System; also at all Ports of Entry) |
| Information | Official page |
Idaho Code §49-1010 (sizes) + §49-1001 (weights) + §49-1004 (permits/fees) current (legislature.idaho.gov, July-2026… · legislature.idaho.gov · in effect since 2026-07-10 · source read 2026-07-10. Fees and rules change; the linked document is always the authority.