New Hampshire OS/OD Overview
Permit Required
Yes – any load exceeding legal size or weight must have a permit from the New Hampshire Department of Transportation (NHDOT) – Bureau of Highway Maintenance, Permits. Single-trip and term permits are issued through the NHDOT permits office.
Legal Limits (Without Permit)
- Width: 8'6"
- Height: 13'6"
- Length: 75' (combo); 53' trailer allowed
- Weight: 80,000 lbs GVW (standard axle limits apply)
Anything over a legal dimension or weight requires an oversize/overweight permit before the move. Superloads beyond routine permit limits require engineering review, route survey, and possible bridge analysis.
Travel Hours
- Standard: Loads 12' or wider may travel from 1/2 hour before sunrise to 1/2 hour after sunset only.
- Weekends & holidays: No travel on Saturdays, Sundays, legal holidays, or the day following a legal holiday.
- Night travel: Generally not permitted for over-dimensional loads; verify lighting and route conditions on the issued permit.
Escort Requirements (General Guidelines)
| Dimension | Escort Requirement |
|---|---|
| Width 12'–14' | 1 civilian front escort |
| Width over 14' | 2 state police escort vehicles |
| Height over 14' | 1 civilian front escort |
| Length 90' or greater | 1 civilian front escort |
| Length 100' or greater | 1 state police escort |
| Front overhang 15' or greater | 1 civilian escort |
| Rear overhang 15' or greater (width 12'+) | 2 civilian escorts (front + rear) |
Detailed Information
ESCORTS: For width 12'–14', 1 civilian front escort is required. For width over 14', 2 state police escort vehicles are required per the permit table. For overall length 90' or greater, 1 civilian front escort is required; for length 100' or greater, 1 state police escort is required. For height over 14', 1 civilian front escort is required.
OVERHANG: A front overhang of 15' or greater requires 1 civilian escort. A rear overhang of 15' or greater combined with a width of 12' or greater requires 2 civilian escorts (front and rear).
RESTRICTED TRAVEL: Loads 12' or wider may travel only from 1/2 hour before sunrise to 1/2 hour after sunset, and may not travel on Saturdays, Sundays, legal holidays, or the day following a legal holiday.
Additional Notes
- "Oversize Load" signs, red/orange flags, and amber warning lights are required on the load and escort vehicles per NHDOT permit conditions.
- Permit conditions issued by NHDOT govern the specific move and may impose requirements beyond these general thresholds.
Source: New Hampshire DOT — Oversize/Overweight Permits. Informational only — always verify against the live permit office before any move; permit conditions control.
