Interpretation ID: aiam3014
Jr
Wagner Electric Corp.
100 Misty Land
Parsippany
New Jersey 07054;
Dear Mr. McGuirk: I regret the delay in responding to your letter regarding Federal Moto Vehicle Safety Standard 127, *Speedometers and Odometers*. You asked which of the following digital speedometer designs was permissible under the standard: (1) A dual display, with one display expressing speeds in mph and the other in km/h, (2) a single display that alternately expresses the speed in mph and km/h, and (3) a single display that, by means of a switch, may be made to express speed in either mph or km/h.; Section 4.1.2 of the standard requires that speedometers be graduate in miles per hour and kilometers per hour. The agency interprets this requirement to mean that both systems of measurement must be simultaneously viewable by the driver. As stated in the March 16, 1978 final rule, the purpose of the dual graduation is to aid motorists in becoming acquainted with the metric system.; Only the firs design meets the requirement. the second design does no show both systems simultaneously. Further, its distracting and potentially confusing nature may draw a driver's attention away from the road for undersirably(sic) long periods of time. The third design might never serve the educational purpose underlying the dual graduations. If left switched to the mph system, as it most likely would be, the speedometer would not contribute at all to the driver;