Idaho Oversize / Overweight Permit Requirements
Legal-without-permit dimension limits, escort and pilot car thresholds, height pole rules, daylight-only windows, and holiday restrictions for Idaho oversize moves.
Legal limits without a permit
In Idaho, you can move a load without an OSOW permit up to these dimensions on the Interstate and designated highways. Anything over the limits requires a permit (and may require escorts — see below).
| Dimension | Without a permit | Permit required when |
|---|---|---|
| Width | 8′6″ (federal limit) | Anything wider |
| Height | 13′6″ | Anything taller |
| Combo length | 75′0″ | Anything longer |
| Gross weight | 80,000 lb | Anything heavier |
Escort and pilot car thresholds
When permitted, the following escort or movement-restriction rules apply in Idaho. Thresholds are conservative — your specific permit conditions may impose tighter limits depending on the route.
| Trigger | Dimension | Threshold | Detail |
|---|---|---|---|
| Front pilot car | Length | 105'0" | Escort required for overall combinations exceeding 105' on 2-lane and undivided highways (IDAPA 39.02.42.010). |
| Police escort | Width | 18'0" | Idaho State Police escort required for widths exceeding 18' or at ISP discretion. Required on US-30, US-93, SH-75 canyon segments (IDAPA 39.02.42.015). |
| Height pole | Height | 15'6" | Front pilot car must carry height-clearance pole for loads taller than 15'6" (IDAPA 39.02.42.010). |
| Rear pilot car | Width | 14'0" | Second pilot car (rear) added when width exceeds 14'. Lead+chase both required on all routes (IDAPA 39.02.42.010). |
| Daylight-only movement | Width | 14'0" | Loads over 14' wide restricted to daylight movement (sunrise to sunset). Night endorsement requires ITD authorization (IDAPA 39.02.42.010). |
| Weekend / holiday restriction | Width | 14'0" | No movement on New Year's, Memorial Day, Independence Day, Labor Day, Thanksgiving, Christmas for loads over 14' wide. Restriction begins noon preceding day (IDAPA 39.02.42.010). |
| Front pilot car | Width | 12'0" | One pilot car (position per route) required for widths over 12' on 2-lane state highways. Front placement typical (IDAPA 39.02.42.010). |
| Certified escort required | Width | 12'0" | Idaho requires ITD-certified escort vehicle operators for all permitted oversize moves. Certification renewed every 2 years (IDAPA 39.02.42.010). |
Stop tracking these rules by hand.
OverSizeTMS encodes the per-state escort and dimension rules for every state plus DC. Enter the load dimensions and route, and the platform tells you which permits, escorts, and time windows apply automatically.
See how it works →Last updated 2026-06-06. Cross-checked against the state admin code.