Interpretation ID: nht79-1.47

DATE: 10/22/79

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Mack Trucks, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: I regret the delay in responding to your letter of July 19, 1979, which requested an interpretation of Federal Motor Vehicle Safety Standard 101-80, Controls and Displays. You asked whether placing the turn signal symbol on the turn signal control shown in your illustration so that the arrows are vertical would comply with the standard.

The answer is no. Section 5.2.1 of the standard requires that the turn signal symbol appear perceptually upright to the driver. The purpose of that requirement is to ensure quick and accurate indentification of the vehicle controls. The upright position of a symbol is determined by referring to column 3 of Table 1 of Safety Standard 101-80. That table shows that the upright position for the turn signal symbol is with the arrows pointing horizontally. Thus, the arrows must point essentially horizontally in the motor vehicle.

Since the symbols required by Safety Standard 101-80 were selected in order to facilitate international standardization and harmonization, it is important that they not be significantly altered from one vehicle to another. This is particularly important in order to ensure that drivers become familiar with the meaning of various symbols including the turn signal symbol.

However, Safety Standard 101-80 does permit manufacturers to supplement the symbols designated in Table 1 of the standard with additional words or symbols for the purpose of clarity. Therefore, nothing in the standard would prevent your company from adding additional symbols, such as curved thinner arrows next to the turn signal symbol, to indicate mode of operation.

SINCERELY,

9/11/79 - SECOND REQUEST

MACK TRUCKS, INC.

July 19, 1979

Administrator, National Highway Traffic Safety Administration U.S. Department of Transportation

Dear Sir:

Subject: Request for Interpretation Turn Signal Control Identification FMVSS 101-80, Controls and Displays

Mack Trucks, Inc. will be introducing a new truck model later this year. The vehicle has been designed to comply with the current requirements of FMVSS 101-80, Controls and Displays. The attached photograph illustrates the instrument panel layout in a prototype vehicle. Since this vehicle is assembled in France, several features differ from current U.S. vehicle designs.

The turn signal control is located on the instrument panel to the lower left of the speedometer. This is a two function control in that horizontal movement switches the headlamps from low to high beam, while vertical movement activates the turn signals.

FMVSS 101-80 requires that this turn signal control be identified by a specified symbol and that the symbol appear perceptually upright to the driver. As we interpret the regulation, the symbol must be rotated 90 degrees from the position shown in the photograph in order to comply with the requirement. However, we feel that this could be confusing because the operation of the turn signal control is vertical. Although we realize that the symbol is there to indicate the function, not the operation, we question whether a driver will understand what the symbol indicates. We believe it is more appropriate to orient the symbol as shown in the photograph so as to reduce the possibility of confusion. (Note: Please disregard the headlamp symbol next to the turn signal symbol on the control since it will not be there on production vehicles.)

We would appreciate your comments and/or recommendations on the orientation of the turn signal symbol as soon as possible since production of these vehicles is scheduled to begin September 1, 1979.

Thomas F. Brown Executive Engineer-Vehicle Regulations and Standards

ATTACH.

bcc: L. F. DONNELLY; L. F. KASACZUN; E. PASCUAL; S. ROBSON; C. D. TREXLER

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