1520                             Laws of Maryland                       Ch. 534

(c)    It is permissible but not required that any vehicle be equipped
with a theft alarm signal device which is so arranged that it cannot
be used by the driver as an ordinary warning signal.

(d)    Every authorized emergency vehicle shall be equipped with a
siren, whistle, or bell, capable of emitting sound audible under nor-
mal conditions from a distance of not less than 500 feet and of a
type approved by the department, but the siren shall not be used
except when the vehicle is operated in response to an emergency call
or in the immediate pursuit of an actual or suspected violator of the
law, in which latter events the driver of the vehicle shall sound the
siren when reasonably necessary to warn pedestrians and other
drivers of the approach thereof.

§ 12-4.01.1. Bells on ice cream sales vehicles.

Vehicles from which ice cream products and similar products are
sold may be equipped with, and the driver thereof may use, a bell not
exceeding 3½ inches in diameter, or a set of bells, provided that no
bell or set of bells shall be operated by mechanical or electrical
means or by any means other than manually, or be amplified by
any electrical or electronic means, or be capable of emitting sound
audible under normal conditions from a distance of more than 4.00
feet; and provided further that no such bell shall be used for any
purpose between the hours of ten o'clock p.m. and eight o'clock a.m.,
or be used as an ordinary warning signal at any time.

§ 12-402. Mufflers; prevention of noise.

(a)    Every motor vehicle at all times shall be equipped with a
muffler in good working order and in constant operation to prevent
excessive or unusual noise and no person shall use a muffler cut-out,
bypass, or similar device upon a motor vehicle on a highway.

(b)    No person shall use on the exhaust or "tailpipe" of a motor
vehicle any extension or other device to cause excessive or unusual
noise.

(c)    The engine, power, and exhaust mechanism of every motor
vehicle shall be equipped, adjusted and operated to prevent the
continuous emission of excessive fumes or smoke, but in no case shall
such emission be

(1)    As dark or darker in shade as that designated as No. 3 on
the Ringelmann Chart, as published by the United States Bureau of
Mines; or

(2)    Of such opacity as to obscure an observer's view to a degree
equal to or greater than does smoke described in paragraph (1) of this
subsection.

(d)    A muffler as used herein is defined as a device consisting of
a series of chambers or baffle plates, or other mechanical design for
the purpose of receiving exhaust gas from an internal combustion
engine, and effective in reducing noise.

(e)    All mufflers and exhaust pipes carrying exhaust gases from
the motor shall be of leak-proof construction.