Idaho Oversize & Overweight Permit Rules

On non-interstate

Escorts begin at 12'1" wide

Width

• Permit required8'7" – 10'

  Black-coded routes (most of the state highway system): ITD map shows "N/A" for width up to 12'. RED-CODED ROUTES: 1 front pilot car is required at 8'7"-10' wide (ITD map, red row). Route color decides — check ITD's Pilot/Escort Vehicle Travel and Vertical Clearance of Structures map for your route.

• Permit required10'1" – 12'

  Black-coded routes: ITD map shows "N/A" for width up to 12'. RED-CODED ROUTES: 1 front plus 1 rear pilot car are required at 10'1"-12'6" wide (ITD map, red row), and red-coded routes cap permitted width at 12'6" (IDAPA 39.03.01.304.01, 311.01.c). Route color decides — check the ITD map for your route.

• Front escort12'1" – 14'

  ITD pilot-car map, black row, "Over width only" 12'1"-14' = "1 Front". If the load is ALSO over 120' long, the same map's combined cell requires more — "Over length & width: L Over 120' | W 12'1"-18' | 1 Front 1 Rear" — so a rear escort must be added in that case. Red-coded routes cap permitted width at 12'6" and require 1 front plus 1 rear below that cap. Over 12' wide is daylight travel only (IDAPA 39.03.01.305.02). On black-coded routes, a load over 12 ft wide and over 120 ft long needs one front and one rear pilot car (ITD pilot/escort vehicle map, Jan. 8, 2025). Red-coded routes are stricter; white-coded routes (the Interstates and some multilane US routes) have no combined rule. Loads over 120 ft move on single-trip permits, whose escort section governs.

• Front + Rear14'1" – 16'

  ITD pilot-car map, black row, "Over width only" 14'1"-18' = "1 Front / 1 Rear". Not available on red-coded routes (12'6" width cap). Daylight travel only. Over 13' wide there are also Boise, Coeur d'Alene, Idaho Falls, Pocatello and Twin Falls peak-hour bans. On black-coded routes, a load over 12 ft wide and over 120 ft long needs one front and one rear pilot car (ITD pilot/escort vehicle map, Jan. 8, 2025). Red-coded routes are stricter; white-coded routes (the Interstates and some multilane US routes) have no combined rule. Loads over 120 ft move on single-trip permits, whose escort section governs.

• Front + Rear16'1"+

  Shipped 3-escort tier retained and now sourced. ITD's map lists "1 Front / 1 Rear" through 18' on black-coded routes; the third is the advance unit IDAPA 39.03.01.306.13 authorizes "when the load is of such extreme dimensions for the route of travel as to require holding opposing traffic at turnouts and intersections" — the ordinary case for a 16'+ load on a two-lane highway. Annual permits stop at 16' wide (311.01.c), so these are single-trip moves whose escort line is set on the permit (306.03). Over 16' wide on US 12 MP 74-174 also triggers Nez Perce-Clearwater Forest review (307.01.a). Above 18' the map is silent. Above 20 ft, this row's escorts are the minimum; the permit sets any more. On black-coded routes, a load over 12 ft wide and over 120 ft long needs one front and one rear pilot car (ITD pilot/escort vehicle map, Jan. 8, 2025). Red-coded routes are stricter; white-coded routes (the Interstates and some multilane US routes) have no combined rule. Loads over 120 ft move on single-trip permits, whose escort section governs.

Height

• Permit required14'1" – 16'

  ITD's pilot-car map carries no height column; the requirement starts above 16'0" (IDAPA 39.03.01.306.02). Over 15' high is daylight travel only on black-coded routes (305.02); red-coded routes are daylight-only regardless and stop at 2 p.m. Friday. Structures under 16 feet of clearance are posted — check ITD's vertical clearance map.

• Front + High pole16'1"+

  IDAPA 39.03.01.306.02: "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." One front unit carrying a deployed non-conductive, non-destructive height pole with a flexible tip (306.09.f). This is route-independent — it applies on red-coded and black-coded routes alike. Annual oversize permits stop at 15'6" high (311.01.c). Above 20 ft, this row's escorts are the minimum; the permit sets any more.

Length

• Permit required53'1" – 75'

  No over-length pilot-car requirement applies at this length on any route color: ITD map, red row "Over length only: Over 75' | 1 Front"; black row "Over length only: Over 120' | 1 Front". First movement from the forest of tree-length logs or poles is exempt up to 110' (IDAPA 39.03.01.306.14).

• Permit required75'1" – 100'

  Black-coded routes need none until over 120' long. RED-CODED ROUTES: 1 front pilot car is required over 75' long (ITD map, red row), and red-coded convoy length is capped at 75' (IDAPA 39.03.01.304.01). Route color decides — check the ITD map for your route.

• Front escort100'1"+

  Shipped 100'1" trigger retained because it is stricter than ITD's black-coded threshold; the position is corrected to front because ITD's map lists "1 Front" for over-length on both red-coded ("Over 75'") and black-coded ("Over 120'") routes and never a rear. Red-coded routes require that front unit from 75'. ITD's black-coded combined rule adds a rear when a load over 120' long is also 12'1"-18' wide ("Over 120' + 12'1"-18' = 1 Front / 1 Rear"); the red-coded combined rule is "Over 75' + 8'7"-12'6" = 1 Front / 1 Rear". Over 120' long is daylight travel only (IDAPA 39.03.01.305.02). Above 200 ft, this row's escorts are the minimum; the permit sets any more. On black-coded routes, a load over 12 ft wide and over 120 ft long needs one front and one rear pilot car (ITD pilot/escort vehicle map, Jan. 8, 2025). Red-coded routes are stricter; white-coded routes (the Interstates and some multilane US routes) have no combined rule. Loads over 120 ft move on single-trip permits, whose escort section governs.

Weight

• Permit required150,000 lbs+

  US 12 ONLY, milepost 74 to 174 (Nez Perce-Clearwater Forest). IDAPA 39.03.01.307 subjects loads exceeding 150,000 lbs (also 16' wide or 150' long) to Forest Service review, and the resulting safety requirements "include, at a minimum ... Ambulances and possible law enforcement escorts to ensure public safety," plus an Idaho State Police safety inspection before the permit issues and one-load-at-a-time monitoring. The law-enforcement escort is discretionary, not automatic, so it is not counted here. Everywhere else in Idaho, ITD publishes no weight-triggered pilot-car requirement at all — its escort map has no weight column, and escorts are set by width, height and length.

On interstate

Escorts begin at 15'1" wide

Width

• Permit required8'7" – 15'

  ITD pilot-car map, white (Interstate) row, "Over width only" 8'7"-15' = "N/A" — no width-triggered pilot car on the Interstate system below 15'1". Independently of the map, IDAPA 39.03.01.306.12 requires a rear escort whenever the width of the load obstructs the driver's view to the rear so they cannot see 200 feet behind them. Loads over 12' wide lose 24/7 privileges and become daylight-only (IDAPA 39.03.01.305.03).

• Rear escort15'1" – 16'

  ITD pilot-car map, white (Interstate) row, "Over width only" 15'1"-18' = "1 Rear". A rear unit is independently required whenever the load's width blocks the driver's view 200 feet to the rear (IDAPA 39.03.01.306.12). Daylight travel only above 12' wide.

• Rear escort16'1" – 18'

  On the Interstate, ITD requires one rear pilot car for a load 15'1" to 18' wide and no front car. A front pilot car may precede the load on sections where it cannot stay within its travel lane, a third (advance) car may be required for extreme dimensions, and a rear car is required whenever the load blocks the driver's view 200 feet behind. Annual permits stop at 16' wide, so these loads travel on single-trip permits and the pilot cars stated on the permit apply. Daylight travel only. Source: ITD Pilot/Escort Vehicle Travel Requirements and Vertical Clearance of Structures map (Jan 8, 2025); IDAPA 39.03.01.305.03, 306.03, 306.11-306.13, 311.01.c.

• Front + Rear18'1"+

  ITD's pilot-car map publishes no Interstate requirement above 18' wide (its Interstate tier is one rear pilot car at 15'1" to 18'). Loads this wide travel only on single-trip permits, and the pilot cars stated in the permit's escort section are required; ITD may add a front car where the load cannot stay within its travel lane and a third (advance) car to hold opposing traffic. Daylight travel only. Source: ITD Pilot/Escort Vehicle Travel Requirements and Vertical Clearance of Structures map (Jan 8, 2025); IDAPA 39.03.01.306.03, 306.11, 306.13, 311.01.c. Above 20 ft, this row's escorts are the minimum; the permit sets any more.

Height

• Permit required14'1" – 16'

  ITD's pilot-car map carries no height column; the requirement starts above 16'0" (IDAPA 39.03.01.306.02). Over 15' high is daylight travel only (305.03). Every state-system structure with less than 16 feet of clearance has its minimum clearance posted in feet and inches, and vertical clearance must be checked against ITD's clearance map.

• Front + High pole16'1"+

  IDAPA 39.03.01.306.02: "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." One front unit carrying a deployed non-conductive, non-destructive height pole with a flexible tip (306.09.f). Annual oversize permits stop at 15'6" high (311.01.c), so these are single-trip moves. Above 20 ft, this row's escorts are the minimum; the permit sets any more.

Length

• Permit required53'1" – 115'

  ITD's map leaves the white (Interstate) over-length pilot-car cells blank. Over 120' long drops the load off 24/7 travel to daylight only (IDAPA 39.03.01.305.03); 120' is also the Interstate convoy length cap (304.01) and the annual-permit combination length cap (311.01.c).

• Permit required115'1" – 150'

  ITD's pilot/escort map (Jan. 8, 2025) lists no over-length pilot car on white-coded routes, which include every Idaho Interstate, so no length escort applies up to 150 ft, though over 120 ft is daylight-only (IDAPA 39.03.01.305.03, .305.11.e, .306.03).

• Permit required150'1" – 200'

  ITD's pilot/escort map (Jan. 8, 2025) lists no over-length pilot car on white-coded routes, which include every Idaho Interstate. Over 150 ft long on the Interstate, additional ITD approval is required (IDAPA 39.03.01.305.11.e); the load moves on a single-trip permit, and a pilot car is required when the permit's escort or restriction section states one (306.03). Over 120 ft is daylight-only (305.03).