Idaho Oversize Permit Cost: Worked Examples

Idaho sells an oversize permit for a flat fee and an overweight permit by the mile. The flat part is small: $30 for an oversize-only single trip and $33 for an overweight one, under IDAPA 39.03.01.107.05. The per-mile part is the road use fee in Idaho Code 49-1004(2), and it grows with every 2,000 pounds on the scale. The four moves below run that math the way the Idaho Transportation Routing and Permitting System (ITRPS) does at checkout, and they show why the route color on ITD's pilot/escort map often costs more than the permit.

The current fee table, legal limits and escort rules sit on the Idaho oversize and overweight permits page. Check it before quoting a job.

Example 1: the 12-foot excavator, and why the route color decides the cost

A contractor moves an excavator from a Boise yard to a job near Mountain Home, loaded 12 feet wide, 13 feet high and 70 feet long, at 78,000 pounds gross. Width is the only limit exceeded. Idaho Code 49-1010(1) sets legal width at 8 feet 6 inches including the load, and the 14 foot height and 75 foot combination length of 49-1010 still hold. So the move buys an oversize-only single trip permit for $30.

Here is why the same $30 permit can cost very different amounts to run. ITD's Pilot/Escort Vehicle Travel Requirements map (dated January 8, 2025) codes every state highway red, black or white:

• On a black-coded route, a load 8 feet 7 inches to 12 feet wide needs no pilot car for width alone. At or under 12 feet wide, 120 feet long and 15 feet high, IDAPA 39.03.01.305.02 lets it travel 24 hours a day, 7 days a week.
• On a red-coded route, the same 12 foot width falls in the 10 feet 1 inch to 12 feet 6 inches band, which takes one front and one rear pilot car. Red routes are daylight travel only, stop at 2 p.m. on Friday or the day before a holiday, and allow no weekend travel (305.01).

So the permit line is $30 either way. On the red route, the job also pays for two pilot cars and loses its nights and weekends.

Now widen the load to 13 feet 6 inches. On a black route that crosses 12 feet 1 inch, so one front pilot joins the move, and above 12 feet wide the map limits the load to daylight travel. It also crosses the 13 foot curfew line in 305.08: from 6:00 to 9:00 a.m. and 4:00 to 6:30 p.m., Monday through Friday, it cannot run I-84 from milepost 26 to 59 in the Boise valley. A 7:30 a.m. Monday departure from Boise fails that rule. A 9:15 a.m. start works.

Example 2: the overweight transformer and the road use fee

A 7-axle combination hauls a non-divisible transformer at 124,001 pounds gross, 200 permitted miles across Idaho. That is past the 80,000 pound interstate cap and the 105,500 pound cap on other highways in Idaho Code 49-1001, so the move needs an overweight single trip permit. Overweight permits go only to non-divisible loads on five or more axles (IDAPA 39.03.01.300.06), and this unit qualifies.

Let's break it down. The permit fee is the flat $33. The road use fee comes from the 49-1004(2) table:

• The Column 1 starting weight for 7 axles is 114,001 pounds.
• This load is 10,000 pounds above it, which is five 2,000 pound increments.
• The rate starts at 4 cents per mile and adds 4 cents per increment: 4 + (5 x 4) = 24 cents per mile.
• Over 200 miles, the road use fee is 200 x $0.24 = $48.
• The permit total is $33 + $48 = $81.

ITRPS calculates and collects the mileage fee when it issues a single trip permit (39.03.01.310.01), so the whole $81 is due at checkout. Treat the figure as a ceiling. Section 49-1004(2)(a) calls the table the maximum allowable permit fee, and 49-1004(2)(d) lets ITD reduce it for axles wider than 8 feet 6 inches or with more than four tires per axle.

The axle count matters as much as the weight. From 5 axles up, each added axle moves both starting weights up 17,000 pounds, which is eight and a half increments. The same transformer on a 6-axle unit starts counting 17,000 pounds sooner, at 97,001 pounds, and pays 32 or 36 cents more per mile than the 7-axle unit, depending on how ITRPS counts the half step. Over 200 miles that is $64 to $72 more for one fewer axle.

Example 3: the Column 2 superload

A 175,001 pound pressure vessel moves 150 miles on a 7-axle combination. At that weight the table switches columns: Column 2 for 7 axles begins at 165,001 pounds, and its rate starts at $1.02 per mile and rises 7 cents per 2,000 pounds.

• The load is 10,000 pounds past the Column 2 start, or five increments.
• The rate is $1.02 + (5 x $0.07) = $1.37 per mile.
• Over 150 miles, the road use fee is 150 x $1.37 = $205.50.
• The permit total is $33 + $205.50 = $238.50.

Idaho has no separate superload fee, so the rest of the cost at this weight is time. A load above the routinely allowed weights needs extra department review and approval, and an engineering analysis when structures sit on the route (315.01). ITD may take up to 3 business days for that analysis on a vehicle up to 250,000 pounds, and up to 10 business days above that (316.01). Any single or steer axle over 35,000 pounds needs bridge approval (315.02). Above 800,000 pounds, a third-party bridge analysis is mandatory at the applicant's cost (316.02).

One route adds its own review. On US-12 from milepost 74 to 174 through the Nez Perce-Clearwater Forest, loads over 150,000 pounds, 16 feet wide or 150 feet long fall under U.S. Forest Service review. That can bring ambulances and law enforcement escorts (307.01). This vessel is over the weight line, so a US-12 routing adds that review to the calendar.

Example 4: the monthly heavy haul and the annual permit

A carrier moves the same non-divisible crane configuration every month. Twelve overweight single trips cost 12 x $33 = $396 in permit fees before any road use fee. The annual overweight/oversize permit costs $128 under 107.05.d, and annual permits bought online cost $5 less (107.06). The fourth single trip of the year ($132 in fees) already passes the annual price.

On an annual permit, the road use fee moves to a quarterly report. Annual overweight holders report laden-only miles at the permitted weight level every quarter, even when the answer is zero miles, and ITD suspends the account when a report is missing (39.03.01.310). The annual permit also runs at the route-color overweight levels in 39.03.01.308, and red routes need a bridge analysis for the specific configuration, route and weights. Loads over the annual levels still go out on single trip permits (300.06.a).

A divisible load follows a different path. Idaho allows up to 129,000 pounds on designated routes with the $45 annual extra length/excess weight permit. That permit is valid only on the routes shown on the Designated Routes Up to 129,000 Pound Map, and the truck must be registered for the higher weight (49-1004(4) and (5)). The per-mile table in 49-1004(2) applies to nonreducible loads, so this permit does not carry it.

What a pilot car adds in Idaho

The route color sets the count, and the rulebook sets the vehicle. Under IDAPA 39.03.01.306, a pilot car is a passenger car or truck of no more than 16,000 pounds that tows nothing. It displays a roof-top OVERSIZE LOAD sign 12 inches high by 5 feet wide, runs amber lights, carries a two-way radio good for half a mile, and packs a STOP/SLOW paddle, three reflective triangles, a fire extinguisher, a hardhat and a first aid kit. A load over 16 feet high adds a front pilot with a non-metallic height pole (306.02). A rear pilot is also required whenever the load blocks the driver's view 200 feet behind (306.12). Idaho has no pilot driver certification requirement in its special permit rules.

The rules that outrank the math

A few Idaho rules change a quote more than any fee cell does. Next steps before checkout:

• Buy before moving. The permit, or a permit number from a permit office, must be in hand before the wheels turn (Idaho Code 49-1004(1)(b)). A hard copy or digital copy rides in the cab.
• Stop at every port. All oversize vehicles must stop at every port of entry for inspection (39.03.01.300.02).
• Watch the wind and the 511 map. A permit becomes invalid en route in winds over 40 mph, in visibility under 500 feet, or on a road marked Difficult on 511 (102.06).
• Know the refund window. Fees are refundable only if Commercial Vehicle Services hears from you within two working days of the start date, or if ITD issued the permit in error (107.03). A reissue or transfer costs $15.
• Stay on state roads. An ITD permit covers state roadways only. County roads and city streets need the local agency's permit unless it has an agreement with ITD (100.03).

The permit line on an Idaho move runs from $30 to a few hundred dollars. The per-mile weight math, the route color and the travel windows decide the rest.