Chapter 05. Safety Standards for Trailers
Regulation .01 Applicability.LinkCopy Citation
The standards, requirements, and procedures set forth in this chapter are applicable to equipment originally installed by the manufacturer or required by federal or State requirement on trailers (including pole trailers, semitrailers, camping trailers, trailers so designed or manufactured for the purpose of moving modular homes, travel trailers) and any questions regarding these standards or specifications shall be referred to the Automotive Safety Enforcement Division of the Maryland State Police. Any person constructing or reconstructing a vehicle shall assure the vehicle meets or exceeds all applicable federal and State safety standards.
Regulation .02 Hitches or Coupling Devices.LinkCopy Citation
Inspect hitches, coupling devices, tongues, or drawbars on trailers and semitrailers for proper alignment, distortion, deformation, cracks, or missing parts. On vehicles equipped with a ball-type hitch, pintle hood, or drawbar means of attachment, inspect for presence, attachment, and size of safety chains or cables.
| Procedures: | Reject Vehicle If: |
|---|---|
| A. Inspect hitches, couplers, tongues, or drawbars on trailers and semitrailers for: |
A. |
| (1) Proper alignment, distortion, deformation, cracks, or missing parts; | (1) Hitch, coupler, tongue, or drawbar is improperly aligned, distorted, deformed, has any cracks or missing parts. |
| (2) Presence and strength of safety chains or cables on vehicles equipped for a ball and hitch, pintle hook, or drawbar means of attachment. |
(2) Safety chains or cables on vehicles equipped for a ball and hitch, pintle hook, or drawbar means of attachment are severely worn, missing, broken, or not of sufficient strength to support the vehicle in the event the primary attachment device becomes uncoupled. |
| B. On trailers or semitrailers to be coupled to a towing vehicle with a fifth wheel, inspect king pin for excessive wear. | (3) Wear on king pin exceeds manufacturer's allowable tolerance. |
Regulation .03 Suspension and Alignment.LinkCopy Citation
A.
Suspension. Inspect the suspension system for missing, broken, damaged, worn, rusted, or modified wheel bearings, springs, or frame that would affect vehicle stability.
(1)
Wheel Bearings. Wheel bearings out of adjustment can cause wander, unequal brake action, and noise due to interference of parts.
(2)
Springs.
(3)
Air Suspension. Some trailers and semitrailers may be equipped with air suspension systems. Inspection of the system consists of checking for air leaks, proper height, and ride level. CAUTION: The inspector should not use a creeper under the vehicle unless the vehicle is properly jacked and supported.
(4)
Shock Absorbers (if equipped).
B.
Alignment. Inspect axles for broken, damaged, worn, rusted, bent, or modified axle beams, spindles, or mountings that affect wheel alignment, tracking, toe-in, caster, or camber enough to affect vehicle stability.
Regulation .04 Brakes.LinkCopy Citation
Trailers and semitrailers to be registered up to 3,000 pounds GVWR are not required to be equipped with brakes. However, if such a trailer or semitrailer is equipped with brakes, all brakes shall meet minimum standards. Trailers and semitrailers to be registered from 3,001 pounds GVWR to 10,000 pounds GVWR shall be equipped with brakes on all wheels of at least one axle. Trailers and semitrailers to be registered over 10,000 pounds GVWR shall have brakes on all wheels. At least one wheel and drum shall be removed from each axle equipped with drum brakes. On disc brakes only wheel assembly removal is necessary. On trailers and semitrailers with brakes on more than one axle, wheel assembly removal shall be on alternate sides. Always inspect a brake assembly which shows evidence of leaking fluid or grease.
A.
Drums and Discs.
B.
Brake Linings or Pads.
C.
Mechanical Linkage.
D.
Hydraulic System.
E.
Air Brake Leakage. Before conducting these inspections, it may be desirable to install in the system an air gauge (0—150 psi) which has 5 or 10 psi increments, so that small changes in pressure can be more easily observed. Also, to eliminate the possibility of leakage being in the system of the towing vehicle, conduct air leakage tests on the uncoupled towing vehicle before inspecting the system of the trailer or semitrailer.
F.
Vacuum System.
G.
Actuator Reserve.
H.
Electric Brakes. Electric brakes are generally used on small and occasionally on large commercial trailers and semitrailers.
I.
Emergency Brake. Every trailer, semitrailer, and pole trailer equipped with air or vacuum actuated brakes and every trailer, semitrailer, and pole trailer with a registered gross weight in excess of 3,000 pounds, manufactured or assembled after June 1, 1970, shall be equipped with brakes of a character to be applied automatically and promptly and remain applied for at least 15 minutes on breakaway from the towing vehicle.
Regulation .05 Tires and Wheels.LinkCopy Citation
A.
Tires.
B.
Wheels.
Regulation .06 Rear Metal Frame.LinkCopy Citation
Every trailer or semitrailer of a gross weight of 3,000 pounds or more when operated upon a highway shall be equipped with a permanent metal frame attached to the underside of the rear of the vehicle. The frame may not be any wider than the width of the vehicle and may not be more than 30 inches above the highway when moving and shall be constructed of heavy gauge steel. The maximum transverse distance from the widest part of the vehicle at the rear to the frame may not exceed 18 inches. The frame shall be constructed so as not to interfere with lights or other warning devices. Any trailer or semitrailer so constructed and maintained so that the body, chassis, or other parts thereof afford protection required by this section, shall be deemed to be in compliance. The provisions of this section do not apply to pole trailers or to vehicles where the installation of the required frame would prevent operation of the vehicle to secure its designed use.
| Procedures: | Reject Vehicle If: |
|---|---|
| A. Rear Metal Frame. Inspect frame for proper size, mounting, interference with lights or warning devices, and type of construction. |
A. (1) Rear protector frame does not conform to requirements. (2) Rear protector frame is missing when required. |
Regulation .07 Rear Wheel Protector Flaps.LinkCopy Citation
Every trailer or semitrailer when operated upon a highway shall be equipped with suitable metal protectors or substantial flexible flaps behind the rearmost wheels of the vehicle to prevent the projection of rocks, dirt, water, or other substances to the rear and to minimize side spray. This section does not apply to pole trailers or other vehicles if the construction is such that complete freedom around the wheel area is necessary to secure the designed use of the vehicle.
| Procedures: | Reject Vehicle If: |
|---|---|
| A. The protectors or flaps shall have a ground clearance of not more than one-third of the horizontal distance from the bottom edge of the protector or flap to the centerline of the axle, provided, however, that no protector or flap need be closer to the ground than 6 inches under any condition of loading. The protector or flap shall extend laterally at least the width of the tire or tires being protected. |
A. Measurement A is longer than 1/3 the length of Measurement B (Figure 5) and the vehicle is not equipped with flaps or protectors or flaps are not of required length. |
| B. If any trailer or semitrailer is so designed or constructed that the objectives of this section are accomplished by reason of fender or body construction or other means of enclosure, either permanent or temporary, then the requirements of this section have been satisfied. |
B. Protector or flap does not extend laterally at least the width of the tire or tires being protected. C. Protectors or flaps are not securely attached to the vehicle. |
Figure 5—REAR WHEEL PROTECTOR FLAP REQUIREMENTS.
Regulation .08 Fenders.LinkCopy Citation
Fender inspection shall include condition, mounting, and coverage of wheels and tires. If the body or fenders of the vehicle do not provide coverage, the vehicle shall then be equipped with suitable metal protectors or substantial flexible flaps behind the rearmost wheels of the vehicle. This section does not apply to pole trailers or other vehicles where the construction is such that complete freedom around the wheel area is necessary to secure the designed use of the vehicle.
| Procedures: | Reject Vehicle If: |
|---|---|
|
A. Fenders shall be securely attached to the vehicle and inspected for tears, sharp or jagged edges, sufficient coverage (1) Provide required coverage of wheels and tires; (2) Are constructed of substantial materials; (3) Are securely attached to the fenders; (4) Have all edges rolled to eliminate sharp or jagged edges; (5) Do not contact tires during different vehicle attitudes. |
A. (1) Fender has tears, sharp or jagged edges. (2) Fender is not securely attached to vehicle. (3) Fender does not extend outward enough to cover the top of the wheel band tire. (4) The rear of the rearmost fenders do not extend downward to the horizontal centerline of the wheel. (5) Front of all fenders do not extend forward from the vertical centerline of the wheel to at least a 45-degree angle of the horizontal centerline. (6) Fender is missing. (7) The vehicle is not equipped with flaps behind the rearmost wheels when required. |
Regulation .09 Lighting.LinkCopy Citation
General Lamp and Reflector Inspection. This includes all original equipment, exterior lighting plus whatever lights are authorized. (For definitions of lighting terms, refer to COMAR 11.14.04.12E and F.) Pole trailers and modular home trailers may have portable lamp devices which attach to the load when in use to comply with applicable regulations.
| Procedures: | Reject Vehicle If: |
|---|---|
| A. Visual Inspection of Lamp Function. Connect trailer or semitrailer to power source of towing vehicle. Turn on night driving lights of towing vehicle and visually inspect the following: |
A. (2) Turn signals do not properly indicate right or left when so activated. |
| (1) Actuate the turn signal lever of the towing vehicle to right and left; and observe function of turn signal lights of trailer or semitrailer (1962 or newer trailers, semitrailers, and pole trailers shall be so equipped). Turn signals shall emit red or amber light. |
(3) Any lamp shows color contrary to law (red or blue light to the front; white light to the rear, except license plate lamp). (4) A required lamp, lens, or reflector is obscured by any object or shielded by a nontransparent material. |
| (2) Depress the brake pedal of the towing vehicle and observe the function of the stop lamps of the trailer or semitrailer (1972 or newer trailers, semitrailers, and pole trailers shall have two red or amber stop lamps, all others one). |
(5) A lamp or reflector is not mounted to properly direct or reflect light. (6) A lamp assembly or reflector is loose or improperly mounted. |
| (3) Observe function of tail lamps of trailer or semitrailer (Red: two on 1972 or newer vehicles; all others, one). |
(7) A tail lamp, stop lamp, or turn signal has a cracked or broken lens which emits a white light to the rear. (8) A lamp, lens, or reflector is not an approved type. |
| (4) Observe function of license plate lamp of trailer or semitrailer (White: May be incorporated in tail lamp). | |
| (5) 1972 and newer model trailers and semitrailers shall be equipped with two red reflectors on the rear. All others, one. (Reflectors may be incorporated in tail lamps.) In addition, every trailer or semitrailer 80 inches or more in overall width shall be, and all other trailers or semitrailers may be, equipped as required in §A(6),(7), (8), and (9). |
|
| (6) Side marker lamps: One amber, front, and one red, rear, on each side. Vehicles over 30 feet in overall length, one amber, centrally located with respect to length of the vehicle. | |
| (7) Reflectors: One amber, front, and one red, rear, on each side. Vehicles over 30 feet in overall length, one amber, centrally located with respect to the length of the vehicle. (Reflectors may be incorporated in side marker lamps.) | |
| (8) Clearance Lamps: Two amber, front, and two red, rear, to indicate the overall width of the vehicle. One on each side of the vertical centerline of the vehicle at the same height and as near the top of the vehicle as possible. If the vehicle is equipped with three red identification lamps on the top rear, the rear clearance lamps may be mounted at the top or bottom of the vehicle. | |
| (9) Identification Lamps: (Required on 1972 or newer trailers and semitrailers). Three red, rear, grouped in a horizontal row with lamp centers spaced not less than 6 inches or more than 12 inches apart and mounted on a permanent structure of the vehicle as close as possible to the vertical centerline of the vehicle. Pole trailers may be equipped with three red identification lamps visible to the rear, mounted on the rear of the cab of the towing vehicle, the bolster, or on the rear of the load provided they are visible. | |
| (10) Modular home trailers may be equipped with a bar light assembly provided it is bolted securely to the rear frame of the trailer. |
Figures 6—COMMERCIAL SEMI TRAILER LIGHTING REQUIREMENTS.
Figures 7—SMALL TRAILER LIGHTING REQUIREMENTS.
Regulation .10 Electrical System.LinkCopy Citation
To save time, the inspector should develop his own plan or sequence for inspecting miscellaneous electrical items, many of which can be inspected while inspecting other items.
| Procedures: | Reject Vehicle If: |
|---|---|
| A. Inspect Electrical System: (1) Wiring shall be well insulated. |
A. (1) Wiring: (a) Insulation is bare, cracked, or broken. (b) Shows evidence of burning or short-circuiting. |
| (2) Connections shall be tight and secure. | (2) Connections are loose or show signs of excessive corrosion. |
Regulation .11 Load Covers.LinkCopy Citation
A.
This regulation does not apply to a:
(1)
Class G (trailer) vehicle registered or capable of being registered under Transportation Article, §13-927, Annotated Code of Maryland, provided no part of the load is within 6 inches of the top of any of the enclosures the load touches;
(2)
Construction vehicle working within the confines of a public works construction work project site as outlined in the construction project's plans and specifications, provided the distance traveled does not exceed 1 mile or the distance specified in an extension granted by the Maryland Department of Transportation;
(3)
Construction vehicle or mining equipment while crossing a highway between construction or mining sites; or
(4)
Vehicle, within the Port of Baltimore for a distance not to exceed 1 mile, carrying a load of loose material between a stockpile or storage facility and a vessel docked at the Port.
B.
A vehicle carrying loose material which is within 6 inches of the top of any of the enclosures the loose material touches, shall have the loose material covered by a firmly attached canvas or similar type covering.
C.
The requirements of this regulation apply only to the issuance and certification of a safety equipment repair order and do not apply to a complete inspection required upon sale or transfer of ownership of a used vehicle. A safety equipment repair order may be certified only if the cover is present, fully covers the top of the bed, and meets the requirements of this regulation.
Chapter annotations
Authority: Transportation Article, §§12-104(b), 23-101—23-105, and 24-106.1, Annotated Code of Maryland
History: Effective date:
History: COMAR 11.14.05 Noise Abatement Program recodified COMAR 11.14.07
History: Regulations .01—.10 Safety Standards for Trailers adopted effective
History: October 31, 1988 (15:22 Md. R. 2557)
History: Regulation .08 amended effective April 1, 1991 (18:6 Md. R. 687)
History: Regulation .11 adopted effective April 1, 1991 (18:6 Md. R. 687)