2023 Maryland Statutes › Transportation › Title 22 - Vehicle Laws -- Equipment of Vehicles › Subtitle 3 - Brakes › Section 22-301 - Brake Equipment Required

(a)    “Driveaway or towaway operation” means any operation in which any motor vehicle, trailer, or semitrailer, singly or in combination, new or used, is the commodity being transported, when one set or more of wheels of the vehicle are on the roadway during the transportation, whether or not the vehicle furnishes the motive power.
(b)    Every motor vehicle, trailer, semitrailer, and pole trailer, and any combination of these vehicles, while operating on a highway in this State, shall be equipped with brakes in compliance with the requirements of this title. All the vehicles and combinations of vehicles shall be equipped with service brakes complying with the performance requirements of § 22-302 of this subtitle and, except as provided in subsection (l) of this section, adequate to control the movement of and to stop and hold the vehicle under all conditions of loading, and on any grade incident to its operation.
(c)    (1)    All the vehicles and combinations of vehicles, except motorcycles, shall be equipped with parking brakes adequate to hold the vehicle on any grade on which it is operated, under all conditions of loading, on a surface free from snow, ice, or loose material.
(2)    The parking brakes shall be capable of being applied in conformance with the foregoing requirements by the driver’s muscular effort or by spring action or by equivalent means. Their operation may be assisted by the service brakes or other source of power, provided that failure of the service brake actuation system or other power assisting mechanism will not prevent the parking brakes from being applied in conformance with the foregoing requirements.
(3)    The parking brakes shall be so designed that when once applied they shall remain applied with the required effectiveness despite exhaustion of any source of energy or leakage of any kind.
(4)    The same brake drums, brake shoes and lining assemblies, brake shoe anchors and mechanical brake shoe actuation mechanism normally associated with the wheel brake assemblies may be used for both the service brakes and the parking brakes. If the means of applying the parking brakes and the service brakes are connected in any way, they shall be so constructed that failure of any one part does not leave the vehicle without operative brakes.
(d)    Every vehicle shall be equipped with brakes acting on all wheels, except:
(1)    Trailers, semitrailers, or pole trailers of a registered gross weight not exceeding 3,000 pounds, provided that:
(i)    The total weight on and including the wheels of the trailer or trailers does not exceed 40 percent of the gross weight of the towing vehicle when connected to the trailer or trailers; and
(ii)    The combination of vehicles, consisting of the towing vehicle and its total towed load, is capable of complying with the performance requirements of § 22-302 of this subtitle;
(2)    Trailers, semitrailers, or pole trailers of a registered gross weight exceeding 3,000 pounds and not exceeding 10,000 pounds that:
(i)    Have 2 or more axles;
(ii)    Are equipped with brakes acting on all wheels of at least 1 axle; and
(iii)    As part of a combination of vehicles, consisting of the towing vehicle and the total load, is capable of complying with the performance requirements of § 22-302 of this subtitle;
(3)    Any vehicle being towed in driveaway or towaway operations, provided that the combination of vehicles is capable of complying with the performance requirements of § 22-302 of this subtitle;
(4)    Trucks, truck tractors, and special mobile equipment manufactured before July 24, 1980 with three or more axles need not have brakes on the front wheels. However, the trucks and truck tractors must be capable of complying with the performance requirements of § 22-302 of this subtitle;
(5)    The wheel of a sidecar attached to a motorcycle or to a motor-driven cycle, or the front wheel of a motor-driven cycle need not be equipped with brakes, provided that the motorcycle or motor-driven cycle is capable of complying with the performance requirements of § 22-302 of this subtitle; and
(6)    Any vehicle equipped with at least 2 steerable axles need not have brakes on the wheels of 1 of the axles. However, the vehicle must be capable of complying with the performance requirements of § 22-302 of this subtitle.
(e)    (1)    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 10,000 pounds, manufactured or assembled after June 1, 1970, shall be equipped with brakes acting on all wheels and of a character to be applied automatically and promptly, and remain applied for at least 15 minutes on breakaway from the towing vehicle.
(2)    Every trailer, semitrailer, and pole trailer with a registered gross weight of more than 3,000 pounds and not more than 10,000 pounds, manufactured or assembled after June 1, 1970, shall be equipped with brakes acting on all wheels of at least 1 axle and of a character to be applied automatically and promptly, and remain applied for at least 15 minutes on breakaway from the towing vehicle.
(f)    Every motor vehicle manufactured or assembled after June 1, 1970, and used to tow a trailer, semitrailer, or pole trailer equipped with brakes, shall be equipped with means for providing that, in case of breakaway of the towed vehicle, the towing vehicle will be capable of being stopped by the use of its service brakes.
(g)    Air brake systems installed on trailers manufactured or assembled after June 1, 1970, shall be so designed that the supply reservoir used to provide air for the brakes is safeguarded against backflow of air from the reservoir through the supply line.
(h)    (1)    Air Brakes. After June 1, 1971, every towing vehicle, when used to tow another vehicle equipped with air controlled brakes, in other than driveaway or towaway operations, shall be equipped with two means for emergency application of the trailer brakes. One of these means shall apply the brakes automatically in the event of a reduction of the towing vehicle air supply to a fixed pressure, which shall be not lower than 20 pounds per square inch nor higher than 45 pounds per square inch. The other means shall be a manually controlled device for applying and releasing the brakes, readily operable by a person seated in the driving seat, and its emergency position or method of operation shall be clearly indicated. In no instance may the manual arrangement be arranged to permit its use to prevent operation of the automatic means. The automatic and the manual means required by this section may be, but are not required to be, separate.
(2)    Vacuum Brakes. After June 1, 1970, every towing vehicle used to tow other vehicles equipped with vacuum brakes, in operations other than driveaway or towaway operations, shall have, in addition to the single control device required by subsection (i) of this section, a second control device that can be used to operate the brakes on towed vehicles in emergencies. The second control shall be independent of brake air, hydraulic, and other pressure, and independent of other controls, unless the braking system is so arranged that failure of the pressure on which the second control depends will cause the towed vehicle brakes to be applied automatically. The second control is not required to provide modulated braking.
(i)    Except as provided in subsection (l) of this section, after June 1, 1971, every motor vehicle, trailer, semitrailer, and pole trailer, and every combination of these vehicles, except motorcycles, equipped with brakes shall have the braking system so arranged that one control device can be used to operate all service brakes. This requirement does not prohibit vehicles from being equipped with an additional control device to be used to operate brakes on the towed vehicles. This regulation does not apply to driveaway or towaway operations unless the brakes on the individual vehicles are designed to be operated by a single control on the towing vehicle, nor does it apply to the operation of electric trailer brakes.
(j)    (1)    Air Brakes. Every bus, truck, or truck tractor with air operated brakes shall be equipped with at least one reservoir sufficient to insure that, when fully charged to the maximum pressure as regulated by the air compressor governor cut-out setting, a full service brake application may be made without lowering the reservoir pressure by more than 20 percent. Each reservoir shall be provided with means for readily draining accumulated oil or water.
(2)    Vacuum Brakes. After June 1, 1971, every truck with three or more axles equipped with vacuum assistor type brakes and every truck tractor and truck used for towing a vehicle equipped with vacuum brakes shall be equipped with a reserve capacity or a vacuum reservoir sufficient to insure that, with the reserve capacity or reservoir fully charged and with the engine stopped, a full service brake application may be made without depleting the vacuum supply by more than 40 percent.
(3)    Reservoir Safeguarded. All motor vehicles, trailers, semitrailers, and pole trailers, when equipped with air or vacuum reservoirs or reserve capacity as required by this section, shall have reservoirs or reserve capacity so safeguarded by a check valve or equivalent device that, in the event of failure or leakage in its connection to the source of compressed air or vacuum, the stored air or vacuum is not depleted by the leak or failure.
(k)    (1)    Air Brakes. Every bus, truck, or truck tractor using compressed air for the operation of its own brakes or the brakes on any towed vehicle, shall be provided with a warning signal, other than a pressure gauge, readily audible or visible to the driver, which will operate at any time that the air reservoir pressure of the vehicle is below 50 percent of the air compressor governor cut-out pressure. In addition, the vehicle shall be equipped with a pressure gauge visible to the driver, which indicates in pounds per square inch the pressure available for braking.
(2)    Vacuum Brakes. After June 1, 1971, every truck tractor and truck used for towing a vehicle equipped with vacuum operated brakes and every truck with three or more axles using vacuum in the operation of its brakes, except those in driveaway or towaway operations, shall be equipped with a warning signal, other than a gauge indicating vacuum, readily audible or visible to the driver, which will operate at any time the vacuum in the vehicle’s supply reservoir or reserve capacity is less than 8 inches of mercury.
(3)    Combination of Warning Devices. When a vehicle required to be equipped with a warning device is equipped with both air and vacuum power for the operation of its own brakes or the brakes on a towed vehicle, the warning devices may be, but are not required to be, combined into a single device that serves both purposes. A gauge or gauges indicating pressure or vacuum is not an adequate means of satisfying this requirement.
(l)    (1)    In this subsection, “surge brakes” means a braking system designed to activate the brakes of a vehicle being towed as a result of the forward pressure of the vehicle against the towing vehicle during deceleration.
(2)    A trailer or semitrailer may be equipped with surge brakes if:
(i)    The trailer or semitrailer has a manufacturer’s gross vehicle weight rating, or registered weight, whichever is less, of 10,000 pounds or less;
(ii)    The combined gross vehicle weight rating, combined registered weight, and the gross combination weight of the trailer or semitrailer and the towing vehicle is 26,000 pounds or less;
(iii)    The vehicle or combination of vehicles is not designed or used to transport 16 or more passengers including the driver of the towing vehicle;
(iv)    The actual gross weight of the trailer or semitrailer and load does not exceed the manufacturer’s gross vehicle weight rating or registered weight, whichever is less;
(v)    The actual gross weight of the towing vehicle and load does not exceed the manufacturer’s gross vehicle weight rating or registered weight, whichever is less;
(vi)    The trailer or semitrailer brakes are designed and connected in such a manner that in case of accidental breakaway of the towed vehicle, the brakes will apply automatically;
(vii)    The vehicle or combination of vehicles is not used to transport hazardous materials of a type and quantity that requires placarding;
(viii)    The vehicle or combination of vehicles is not used to transport liquids or gases contained in packaging that exceeds a capacity of 119 gallons;
(ix)    The trailer or semitrailer has a gross weight rating, registered weight, or gross weight, whichever is greater, that is not more than one and one-half times the gross weight rating or registered weight, whichever is less, of the towing vehicle; and
(x)    For vehicles used for commercial purposes, the trailer or semitrailer is used only in intrastate commerce.