Current through September 16, 2024
New motor vehicles tested for compliance with NAC 484D.155,
together with any auxiliary equipment that would be in use while the vehicle is
in motion on the highway, must be operated as follows:
1. Trucks, truck-tractors and buses that have
a manufacturer's gross vehicle weight rating of 6,000 pounds or more must be
operated under the condition of grade, load, acceleration, deceleration and
gear selection that is found to give the maximum noise at a speed up to 35
miles per hour.
2. Trucks,
truck-tractors and buses that have a gross vehicle weight rating of less than
6,000 pounds and passenger cars must be tested at curb weight plus weight of
the driver and when necessary one technician, and be operated as follows:
(a) Motor vehicles equipped with three-speed
or four-speed manual transmissions must be operated in second gear. Vehicles
equipped with four-speed manual transmissions must also be operated in second
gear. Vehicles equipped with five-speed manual transmissions must be operated
in second gear. Vehicles equipped with automatic transmissions must be operated
with transmissions engaged in low gear. Vehicles which reach maximum rated
engine speed at less than 30 miles per hour or before reaching a point 25 feet
beyond the microphone line must be operated in the next highest gear. Auxiliary
step-up ratios or overdrive must not be engaged on vehicles so
equipped.
(b) The vehicle must
proceed along the test path at a constant approach speed of 30 miles per hour.
When the front of the vehicle reaches a point 25 feet from a line through the
microphone intersecting the path of the vehicle at right angles, the throttle
must be fully opened. The throttle must be held open until the rear of the
vehicle is approximately 100 feet beyond the microphone, or until the maximum
rated engine speed is obtained at which point the throttle is gradually closed.
Wheel slip must be avoided during this test.
3. Motorcycles must be operated as follows:
(a) Motorcycles must be operated in second
gear. Vehicles which reach maximum rated engine speed at less than 30 miles per
hour or before reaching a point 25 feet beyond the microphone line must be
operated in the next higher gear.
(b) The vehicle must proceed along the test
path at a constant approach speed which corresponds to either an engine speed
of 60 percent of maximum rated engine speed or at 30 miles per hour, whichever
is lower. When the front of the vehicle reaches a point 25 feet from a line
through the microphone intersecting the path of the vehicle at right angles,
the throttle must be fully opened. The throttle must be held open until the
rear of the vehicle is approximately 100 feet beyond the microphone, or until
the maximum rated engine speed is obtained at which point the throttle is
gradually closed. Wheel slip must be avoided during this test.
4. Deceleration tests must be
conducted on vehicles when there is an indication that the deceleration noise
might exceed the acceleration noise. The vehicle must proceed along the test
path in the gear which was used for the acceleration test and at a constant
approach speed equal to the maximum rated engine speed. When the front of the
vehicle reaches a point 25 feet beyond a line through the microphone, the
throttle must be closed as rapidly as possible.
[Dep't of Motor Veh.,
Noise Emissions Reg. § VII subsec. B, eff. 1-21-72] - (Substituted in
revision for NAC 484.180)
NRS
484D.410
