Ch. 355

2004 LAWS OF MARYLAND

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) [After] 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

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