Interpretation ID: nht93-6.7

DATE: August 12, 1993

FROM: Dennis G. Moore -- President, Sierra Products Inc.

TO: John Womack -- Acting Chief Council, NHTSA

TITLE: None

ATTACHMT: Attached to letter dated 11/16/93 from John Womack to Dennis G. Moore (A41; FMVSS 108)

TEXT:

The International Marine Trade & Conference Show will be held in Chicago September 9 through September 12 and I would like to use this timely opportunity to clarify to its members the meaning of "to represent the width" used in FMVSS #108 to tell Vehicle Manufacturers where to locate Clearance lights. If at all possible, could you please clarify what this term means in time for this Show using terminology that are clear to all concerned.

LEGAL INTERPRETATION REQUEST

In a June 23, 1992 letter I came across in the files at the D.O.T., you recently used the term "as nearly as possible to indicate the overall width" in response to the same question I am posing. I feel answers like this are leading the Vehicle Industry to continue what is already a wide spread problem....misplaced Clearance lights.

Obviously there exists extreme confusion as to the term "to represent the width" when referring to where Clearance lights should be mounted on Vehicles over 80" in width.

Inadvertently, you have encouraged the rear and front mounting surfaces of large vehicles to be used for Clearance lights by using the "near as possible" term, further propagating the misunderstanding of the original intent of this Law.

From SAE and NHTSA archives, the original purpose of Clearance Lights was "to mark the extreme sides of the vehicle" (1947 SAE Handbook, Page 713, copy attached). Old photographs of trucks in this era show Commercial Trucks and Trailer Manufacturers always mounted the lights to indicate at least the extreme width of the vehicle.

Additionally, as you should know, Federal and State laws put into affect many years ago, have made specific allowances for Clearance Lights to protrude up to 20" (10" on each side) beyond the vehicle's maximum width (96" then...102" today).

In times when NHTSA is trying to improve "conspicuousness" of large vehicles to decrease accidents in which these type vehicles are involved, it is preposterous that the present term, "to represent the width" has come to mean....to represent "somewhere near" the width. Simply observing large vehicles, RV's, etc. on any highway clearly demonstrates this misunderstanding. It only takes a fraction of an inch of interference for one vehicle to "sideswipe" another, thereby causing what can result in a catastrophic accident. Yet, it is not uncommon to see Clearance lights

mounted as much as 6" to 8" "inside" the side extremities of huge vehicles.

I have heard of industry "hearsay" arguments that it is best to mount Clearance Lights so that they're protected from being "knocked off." I ask!....wasn't and isn't it the purpose of these lights to get knocked off instead of allowing "sideswiping" which results in hard contact of two vehicles. Isn't the intent of the 10" Government side "stick out" allowance (on each side) to deliberately sacrifice these lights to avoid accidents?

I've also heard of "hearsay" arguments from "Leaders" in the Boat Trailer and Boat Trailer Lighting Industry say that somewhere "it is written in the law that it's allowable to mount Clearance Lights to "split" the protruding area represented by fenders," whereas I know of no such allowances in the law and I don't believe you do either.

I think widespread deviations from the initial intent of the Law has occurred and Clearance Lights have become decorative rather than functional. The detailed Lighting Rules initiated in 1969 required that a Clearance Light cover both "Outboard" and "Inboard" line of sight areas and that the Vehicle couldn't obstruct the Inboard line of sight.

As a result, it became immediately apparent to Vehicle Manufacturers they couldn't continue to mount a Clearance light on the side of a vehicle as they had been doing to this point and still maintain an "inboard" line of sight. Thus, this 1969 "Inboard" requirement started Vehicle Manufacturers mounting Clearance Lights on the Front and Rears of Vehicles because of corner radiuses, etc. Since they couldn't represent the extreme width easily, they started an "in the ballpark" compromise. This was never challenged by NHTSA and has been unchallenged to this day.

Fortunately, in 1974, the "inboard" visual requirement for Clearance lights was rescinded, but unfortunately, the practice of mounting Clearance Lights on the rear and front well inside of the true width still carried on.

Presently, there are a number of lights in the marketplace specifically designed to be mounted on the sides of Large Vehicles. They are designed to represent slightly beyond the extreme width of the vehicle. In many cases, these lights can second as Sidemarker lights as well and were designed to be used to indeed represent the extreme width (and slightly beyond) of a large vehicle. These lights are used by some Large Vehicle Manufacturers but many other Vehicle Manufacturers still avoid their use because of the confusion in the term "to represent the width."

Any of these lights cost only one to three dollars; therefore if they're ruined in "sideswipe contact," little is lost; however, a possible "bounce off," "cross lane" type "multi-vehicle" accident is avoided. This is the type of accident where inherently no one seems to know what started it, so misplaced Clearance Lights are rarely blamed nor reported nor recorded in government files. I feel common sense would indicate these types of accidents are taking place.

I am requesting a legal clarification detailing where FMVSS 108 requires a Clearance Light to be mounted.