Interpretation ID: nht71-1.10

DATE: 06/04/71

FROM: AUTHOR UNAVAILABLE; R. L. Carter; NHTSA

TO: Voevodsky Associates, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of May 19 concerning installation by vehicle manufacturers of your Cyberlite system as original equipment on motor vehicles.

You ask two questions:

"(1) Is the installation . . . of the Voevodsky-Cyberlite System . . . permissible under Motor Vehicle safety Standard No. 108?"

"(2) If the installation . . . is permissible . . . does a state have the authority to (a) require the system, (b) permit the system, or (c) prohibit the system.

Section 103 (d) of the National Traffic and Motor Vehicle Safety Act of 1966 in effect permits the States to regulate any aspect of performance that is not covered by a Federal motor vehicle safety standard. As discussed in your meeting with NHTSA representatives on May 13, Standard No. 108 permits the installation of additional lighting equipment that does not impair the effectiveness of the required lighting equipment. It does not appear that the Cyberlite system, with the performance characteristics and location on the vehicle as you have described it, would impair the effectiveness of other vehicle lamps, and its installation is considered permissible under Standard No. 108. Since Standard No. 108 does not prescribe requirements for this aspect of performance, the States are free to require, permit, or prohibit the use of your warning system.

Sincerely,

VOEVODSKY ASSOCIATES, INC.

May 19, 1971

Laurance R. Schneider National Highway Traffic Safety Agency

Dear Mr. Schneider:

On 13 May 1971 I met with Richard Dyson, Lewis Owen, and Mike Esposito and on 14 May 1971 I met with Robert H. Cannon, Jr. As a result of these meetings I was directed to write to you for an opinion from the National Highway Traffic Safety Agency on the following legal questions.

(1) Is the installation on motor vehicles of the Voevodsky-Cyberlite System as described in the submission under Docket No. 69-19; Notice 1, permissible under Motor Vehicle Safety Standard No. 108?

(2) If the installation on motor vehicles of the Voevodsky Cyberlite System is permissable under Motor Vehicle Safety Standard No. 108, does a state have the authority to (a) require the system, (b) permit the system, or (c) prohibit the system?

The Voevodsky - Cyberlite System is an intervehicular deceleration warning communications system in which a red or amber warning light is center mounted on the rear of the leading vehicle at the same height as existing stop lights to communicate a component of deceleration initiated by the driver of the leading vehicle to the driver of a following vehicle. A device for measuring the deceleration of the leading vehicle is rigidly attached to this vehicle. The warning light is pulsed in a controlled fashion at a rate which varies exponentially with a component of deceleration. This component of decelaration will take into account the intensity of break action, the deceleration caused by all other frictional forces including aerodynamic, which vary from vehicle to vehicle and lastly, the deceleration caused by the component of gravitational forces parallel to the slope of the road. The exponential variation compensates for the neural response of the following driver to the pulsed coded light. The "on" time per cycle of the light pulse is also shortened with increasing frequency rate to provide a redundant warning. In practice, the maximum delay time for the driver in the following vehicle to obtain the knowledge of the degree of deceleration of the lead vehicle is 1/2 second while the deceleration is minimum; and the minimum delay time is approximately 1/14 second when the deceleration is maximum, thereby defining the band width of the information system. A 50% increase in frequency of the light pulses from 1.0 pulses per second to 7.6 pulses per second for each 0.1 "g" increase in deceleration from 0 to 0.5 g's provides the desired exponential relationship and the 50% duty cycle provides the necessary information band width.

Sincerely yours,

Dr. John Voevodsky

cc: Robert H. Cannon,

Richard Dyson;

Mike Esposito;

Lewis Owen