Maryland OS/OD Overview
Permit Required
Yes – all oversize or overweight vehicles require a permit from the Maryland State Highway Administration (SHA), Motor Carrier Division.
Legal Limits (Without Permit)
- Width: 8'6"
- Height: 13'6"
- Length: 65' (combo); 53' trailer allowed
- Weight: 80,000 lbs GVW
Permitted Load Maximums (Typical Upper Limits)
- Width: Up to 16' with proper escorts
- Height: Over 14'6" requires route survey and structure clearance
- Length: Over 120' allowed with route and traffic analysis
- Weight: 250,000+ lbs with axle spacing and engineering approval
Superloads may require several business days for approval and coordination with local jurisdictions.
Travel Hours
- Standard: ½ hour after sunrise to ½ hour before sunset
- Weekend: No travel allowed on Sundays; Saturday travel limited after noon
- Holidays: No movement on major holidays or holiday weekends
- Night travel: Only allowed under special conditions (usually under 12' wide)
Escort Requirements (General Guidelines)
| Dimension | Escort Requirement |
|---|---|
| Width > 12' | 1 Escort (front or rear depending on route) |
| Width > 14' | 2 Escorts (front and rear) |
| Height > 14'6" | High pole escort and route survey |
| Length > 120' | 1 or 2 Escorts depending on road type and traffic volume |
Additional Notes
- “Oversize Load” signs, red/orange flags, and amber flashing lights are required
- Urban areas like Baltimore and DC suburbs may have time-of-day travel restrictions
- Permits are processed through the Maryland One Hauling Permit System
Detailed Information
PERMITS: Permits valid for five travel days. Must have permit prior to entering the state.
OPERATING TIME: Loads not exceeding 12’ wide, 14’6” high, 75’ long, and 120,000 pounds may travel from 12:01a.m. on Monday to noon on Saturday. No Sunday travel. (see Restricted Travel, below, for some exceptions).
RESTRICTED TRAVEL: No movements across any toll facilities allowed from noon Friday until 9:00 A.M. Monday. This restriction is also applied to all of I-95 from Baltimore to the Delaware line. Over 12' wide or over 92,000 pounds can only travel 9:00 A.M. to 3:30 P.M. (and Saturday until Noon) when on the Capital Beltway I 495/I-95 and Baltimore Beltway I-695. If 14' wide or more, travel is only allowed from 9:00 A.M. to 3:30 P.M. (and Saturday until Noon on any highway. No travel on six major Holidays and Holiday weekends (check with the Permit Office).
BALTIMORE CITY: Baltimore permits for the predefined route into or out of Dundalk Marine Terminal are now included with the Maryland state permit provided the dimensions are under 120,000 pounds, 12' wide, 14'6" high and 85' long. Loads with other Baltimore destinations or origins, or loads exceeding these dimensions have to be ordered separately from Baltimore City, which is usually slow with a 24-hour (minimum) turn-around time.
LEGAL DIMENSIONS: Width: 8'6" Interstate & designated highways, 8' all other roads. Height: 13'6" (over 13'6" not permitted on flat-bed). Length: 53' semi-trailer on Interstate and designated highways, 48' trailer all other roads. Trailers over 48' are not to exceed 41' kingpin to center of rear tandem axles, and not more than 4' set back from front of trailer to kingpin. Overhang: 3' front, 6' rear Weight: 80,000 Gross Single – 20,000 Tandem – 34,000 Tridem – 42,500
ROUTINE PERMIT LIMITS: Width: 16' Height: 16' (overheight cannot be permitted on a flatbed) . Over 14'6" now requires a route survey. Length: 120' Weight: 120,000 (non-Interstate) to 150,000 (Interstate) Single – 27,000 Tandem – 52,000 Tridem – 63,000 Loads exceeding these dimensions are treated as super loads. Over 150,000 pounds gross on any Interstate routes is a superload.
ESCORTS: Width: Over 13' – 1 escort; 14' or more – 2 escorts; at 16' or more – Police escort.
Montgomery and Prince George Counties: loads over 12' wide on 2-lane undivided – 2 escorts
Length: Over 85' – 1 escort; 140' or more – 2 escorts. Height: 14'6" or more – 1 escort with height pole (some routes may have other requirements), and a route survey must accompany application. Weight: Over 120,000 pounds – 1 civilian escort, and Police escort is required on entire route if any part of the route is
on non-Interstate highways; over 130,000 pounds - Police escort is required even on Interstate-only routes.
MISCELLANEOUS: Construction equipment can have blade or bucket attached up to 12' wide. Detached blade and dozer cannot be hauled on same load if it is overweight. The blade has to be hauled separately.
SIGNS, FLAGS & LIGHTS: "Oversize Load" or "Wide Load" signs are required if the vehicle and load exceeds 9' in width.