NAC484D.170. Noise emission measurements: Microphone and technician.

The microphone and technician must be positioned as follows:

     1. The microphone must be located at 49 to 51 feet from the centerline of the lane of travel of the vehicle at a height of 3 1/2 to 4 1/2 feet above the plane surface of the roadway surface.

     2. The microphone must be oriented relative to the source of sound in accordance with the instrument manufacturer’s instructions. Where the instruction manual is vague or does not include adequate information, a specific recommendation must be obtained from the manufacturer.

     3. The technician making direct readings of the meter must be positioned relative to the microphone in accordance with the instrument manufacturer’s instructions. Where the instruction manual is vague or does not include adequate information, a specific recommendation must be obtained from the manufacturer.

     4. No bystander may be closer than 50 feet from the microphone and the vehicle being tested, except for a witness or trainee who shall be positioned beyond the technician on a line through the technician and the microphone.

     [Dep’t of Motor Veh., Noise Emissions Reg. § VII subsec. A, eff. 1-21-72]—(Substituted in revision for NAC 484.170)