How to read an Idaho oversize permit
ITD issues permits through ITRPS (Permits4Idaho), which builds the route from an origin, a destination and any via points, and shows it as a one-line Route Description plus a turn-by-turn Driving Directions table. Your travel hours and escorts depend on whether each road is red-coded or black-coded on ITD's Pilot/Escort Vehicle Travel and Vertical Clearance of Structures Map.
Issued by the Idaho Transportation Department through Idaho Transportation Permits System (ITRPS), at Permits4Idaho. Written from ITD's published rules; we haven't read a real Idaho permit yet.
How to read the route
In ITRPS the trip comes with a short Route Description and a Driving Directions table. In ITD's example the Route Description reads '==> I-90 WA Line <==I-90==> I-90 MT Line <==': the start and end are inside the arrows, with the roads between. Read the table top to bottom: drive the Miles on the road in the Route column, then do what the To column says, like 'Continue straight on I-90'. Distance is the running total and Time the running drive time. An Escort Conditions box lists each part of the route that needs a pilot car, like 'One certified pilot car in the rear on I 90 from Origin to Destination.'
Columns, left to right: Miles · Route · To · Distance · Time.
Road names on Idaho permits
| On the permit | Means |
|---|---|
| I-90 | Interstate 90 |
| US-30 | U.S. Route 30 |
| I-84, MP 26 to MP 59 | Interstate 84 from milepost 26 to milepost 59, the Boise valley stretch in ITD's rush-hour rule |
| I-90;WA;Post Falls | Where I-90 crosses the Washington state line, by Post Falls: road; state; nearby town |
Where the route starts and ends
In ITD's example the origin is written 'I-90;WA;Post Falls' and the final destination 'I-90;MT;Mullan': the road, the state line it crosses, and the nearby town. You enter an origin, a destination and any via points, and you can add up to 5 split trips to one route.
Conditions to watch for
Red-coded routes
On red-coded routes, oversize loads move in daylight until 2 p.m. on Friday or the day before a holiday, with no travel Saturday or Sunday. Travel resumes at sunrise Monday or the day after the holiday. A single-trip permit may set different times. Source
“Daylight travel until 2 p.m. on Friday or the day before a holiday”
Black-coded routes, Interstates and holidays
On black-coded routes and Interstates, loads up to 12 feet wide, 120 feet long and 15 feet high can travel 24 hours a day, 7 days a week. Bigger loads follow the map's restrictions, and on black-coded routes they stop before 4 p.m. the day before a holiday. The holidays are New Year's Day, Memorial Day, Independence Day, Labor Day, Thanksgiving and Christmas. Source
“limited to traveling before 4:00 p.m. on the day preceding a holiday”
Rush hours
Loads more than 13 feet wide can't move during weekday commuter hours, 6 to 9 a.m. and 4 to 6:30 p.m., in listed areas. The areas include the Boise valley (I-84 MP 26 to 59), Coeur d'Alene (I-90 MP 0 to 17), Idaho Falls, Pocatello, Twin Falls, and within a mile of Eagle, Emmett, Garden City, Middleton and Star. Source
“the times of heavy commuter traffic will be 6:00 a.m. to 9:00 a.m., and 4 p.m. to 6:30 p.m. local time”
Pilot cars
On a single-trip permit, you need a pilot car whenever the permit's escort or restriction section says so; ITRPS lists these by route segment. Loads over 16 feet high need a front pilot car with a non-metallic height pole. Source
“A pilot car is required for a single trip any time it is so stated in the escort section”
Signs and flags
Every over-width load shows 'Oversize load' signs at least 12 inches by 5 feet, black on yellow with 8-inch letters, on the front or roof of the truck and the rear of the load. Flags are red or fluorescent orange, at least 18 inches square, on over-width loads and on rear overhangs of 4 feet or more. Source
“Oversize load signs will be required on all vehicles and/or loads exceeding legal width.”
Lights after dark
Over-width loads moving from 30 minutes after sunset to 30 minutes before sunrise, or when you can see less than 500 feet, must show lights marking the load's outer edges. These are in addition to normal clearance lights. Source
“traveling thirty (30) minutes after sunset to thirty (30) minutes before sunrise”
Easy to miss
- The same load can have different hours on different roads. Check whether each road on your route is red-coded or black-coded on ITD's Pilot/Escort Vehicle Travel and Vertical Clearance of Structures Map.
- An ITD permit covers only state roadways, as described on the permit by route number or otherwise. County roads and city streets are not covered unless a local agreement says so.
- A front overhang over 7 feet limits you to daylight travel on two-lane, two-way highways.
Questions
What are red routes and black routes on an Idaho oversize permit?
They are road codes on ITD's Pilot/Escort Vehicle Travel and Vertical Clearance of Structures Map. Red-coded routes allow daylight travel only, end at 2 p.m. Friday, and close on weekends. Black-coded routes let loads up to 12 feet wide, 120 feet long and 15 feet high run around the clock.
Can oversize loads travel at night in Idaho?
On Interstates and black-coded routes, loads up to 12 feet wide, 120 feet long and 15 feet high can travel 24 hours a day. Over-width loads moving after dark need lights marking the load's outer edges.
What holidays restrict oversize loads in Idaho?
New Year's Day, Memorial Day, Independence Day, Labor Day, Thanksgiving and Christmas. On red-coded routes travel ends at 2 p.m. the day before; on black-coded routes, loads over the 24-hour limits stop before 4 p.m. the day before. Travel resumes at sunrise the day after.
Sources
Your permit is the legal document; follow everything it says. Rules change; check ITD's site before you move.Last checked October 2026.