New Mexico Height, Width, and Length Limits Explained

Nov. 8, 2025, 7:39 p.m.
Understanding New Mexico’s size and weight limits is critical for staying compliant and avoiding fines or delays. Whether you’re an interstate hauler or operating within New Mexico, the state enforces specific legal limits for commercial vehicles under NMSA 1978, Section 66-7-404 to 66-7-410 and NMDOT rules.
New Mexico Height, Width, and Length Limits Explained

1. Legal Size Limits (Without a Special Permit)

These are the maximum dimensions a commercial motor vehicle can operate on New Mexico highways without obtaining an oversize permit.

Measurement Maximum Legal Limit Notes
Width 8 feet 6 inches (102 inches) Mirrors and safety devices excluded. Applies to most interstates and primary highways.
Height 14 feet Drivers are responsible for ensuring adequate clearance under bridges, powerlines, etc.
Single Vehicle Length 45 feet Applies to straight trucks and buses.
Combination (Truck + Trailer) 65 feet total Includes semis and trailers unless operating under specific exemptions.
Trailer Length (Semi-Trailer) 57 feet 6 inches Allowed on designated National Network routes (Interstate and selected highways).
Front Overhang 3 feet Load cannot extend more than 3 feet beyond the front bumper.
Rear Overhang 6 feet Loads extending more than 4 feet require red flags (daytime) or red lights (night).

2. Oversize Permit Requirements

If your vehicle or load exceeds any of the above dimensions, you must obtain an Oversize Permit from the New Mexico Motor Transportation Division (MTD).

Common Oversize Thresholds:

  • Width over 8’6”

  • Height over 14’

  • Overall length over 65’

  • Trailer length over 57’6”

Permit Types:

  • Single-Trip Permit: Valid for one move within specified routes and dates.

  • Annual Permit: For repeated operations along pre-approved routes (e.g., construction or farm equipment).

3. Escort and Pilot Car Requirements

Depending on the load dimensions and route, escorts may be required:

  • Width over 12 feet: One front and one rear escort vehicle.

  • Height over 15 feet: May require route survey and pilot car.

  • Length over 90 feet: One or more escorts depending on location and time of travel.

4. Travel Time Restrictions

  • Daylight Travel Only: Most oversize loads must move from ½ hour before sunrise to ½ hour after sunset.

  • No Night or Weekend Travel: Unless specifically allowed by the permit.

  • Holiday Restrictions: Movement is restricted on major holidays like Thanksgiving, Christmas, and Independence Day.

5. Enforcement and Fines

Violations of size limits or permit conditions can result in:

  • Fines up to $500 per violation

  • Detention until a proper permit is obtained

  • Possible revocation of oversize privileges for repeat offenders

6. Helpful Resources

  • New Mexico Motor Transportation Division (MTD): https://www.mvd.newmexico.gov/motor-carriers/

  • NMDOT Oversize/Overweight Permits: https://permits.dot.state.nm.us/

  • New Mexico Statutes on Vehicle Size & Weight: https://laws.nmonesource.com/

Final Tips

  • Always verify current restrictions before traveling—construction zones and bridge limits may temporarily change.

  • Keep a copy of your oversize permit and route map in the vehicle at all times.

  • If your load is unusual (tall equipment, wind blades, etc.), call the Permit Office for guidance before applying.

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