Maryland trailer laws and regulations
Maryland trailer rules from the MVA: brake thresholds, titles, length and width limits, mirror requirements and the lighting list.
Maryland treats trailers like passenger vehicles for paperwork. Every trailer used on public roads needs a title and registration through the MVA, and used trailers being registered for the first time need a safety inspection. Brakes kick in at 3,000 lb GVWR on at least one axle, and at 10,000 lb GVWR on all wheels.
The state writes its lighting rules in unusual detail, more than most neighbours, so if your trailer is 80 inches wide or more you’ll want to skim that section before you commit to a build.
Quick reference
| Item | Maryland rule |
|---|---|
| Brakes on one axle | Trailers 3,000 lb GVWR or more |
| Brakes on all wheels | Trailers 10,000 lb GVWR or more |
| Title and registration | All trailers on public roads |
| Used trailer inspection | Required at first registration |
| Max trailer length | 40 ft including bumpers |
| Max combo length | 55 ft including bumpers |
| Max width | 102 in |
| Max height | 13 ft 6 in |
| Class A tow limit | 10,000 lb |
| Class E truck tow limit | 20,000 lb GVW |
Registration and titling
All trailers used on Maryland roads have to be titled and registered through the MVA. To get a trailer titled you’ll need the VIN, a bill of sale, photo ID, proof of insurance and documented purchase price. Used trailers being titled and registered need to pass a Maryland safety inspection.
Trailers with a gross weight of 3,000 lb or less pay a biennial registration fee of $51.50 as of recent fee schedules. Heavier trailers pay more, scaling with weight.
General towing rules
Maryland sorts vehicles into classes for what they can pull. Class A passenger vehicles and Class M multipurpose vehicles top out at 10,000 lb of trailer, and they can only pull boat trailers, camping trailers, travel or house trailers, and utility trailers. Class E trucks can pull up to 20,000 lb GVW.
Nobody is allowed to ride in a trailer while it’s being towed on a highway.
Dimensions
The trailer body maxes out at 40 ft including bumpers. Tow vehicle plus trailer combined can’t exceed 55 ft, also including bumpers. Width is 102 inches, height is 13 ft 6 in.
Hitches, chains and couplings
Every full trailer needs a tow bar with a means of attachment to both the tow vehicle and the trailer. The hardware has to be rated for the load, mounted without excessive slack, and locked so the trailer can’t separate by accident.
Full trailers and semi-trailers also need at least one safety chain or cable coupled directly to the frame of the tow vehicle, plus to the trailer and the tow bar. The mounting point on the tow vehicle needs to be strong enough that the chain doesn’t tear the bumper or hitch frame loose under load.
Lighting rules
Maryland’s lighting list is long. The basics:
- Two rear tail lamps emitting red light visible from at least 1,000 ft. Trailers built before June 1, 1971 can get by with one tail lamp visible from 300 ft.
- A white light on the rear license plate visible from 50 ft.
- Two or more red reflectors on the rear, visible from 100 to 600 ft. Pre-July 1971 trailers can use one reflector.
- Two stop lamps (red or amber) on trailers built after July 1, 1971, visible from 300 ft.
- Electric turn signals front and rear on trailers built after July 1, 1971.
Wider trailers (80 inches or more) add clearance lamps, identification lamps in a horizontal row spaced 6 to 12 inches apart, and side marker lamps and reflectors at the front and rear corners of each side. Clearance lamps mount to show the widest point of the trailer (mirrors don’t count) and as close to the top as practical.
Speed limits
Maryland doesn’t publish a separate towing speed. The posted limit applies. If your trailer is swaying or fishtailing at the limit, you can be pulled over for an unsafe combination even though you’re not technically speeding.
Mirror rules
If your trailer blocks the interior rear-view mirror, the tow vehicle needs two outside mirrors, one on each side. That’s the operative requirement. Slip-on extender mirrors handle wider loads where the side mirrors alone don’t cut it.
Brake rules
The parking brake on the tow vehicle has to hold both the tow vehicle and the trailer stationary on any grade. From there, brake requirements scale with trailer weight:
- 3,000 lb GVWR or less: no trailer brakes needed if the trailer is under 40% of the tow vehicle’s weight and the tow vehicle can stop the combination.
- 3,000 to 10,000 lb: at least one axle braked, with two or more axles on the trailer. Combined braking has to stop the loaded combination.
- 10,000 lb and over: brakes on all wheels.