Interpretation ID: nht75-4.26

DATE: 06/10/75

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

TO: Hickman Hampel Corp.

TITLE: FMVSS INTERPRETATION

TEXT: This is in response to your letter of March 10, 1975, petitioning the National Highway Traffic Safety Administration to authorize the use of tempered glass for motorcycle windscreens.

As you know, Standard No. 205 and USAS Z26.1 prohibits the use of tempered glass in motorcycle windscreens. The rationale for this requirement is that tempered glass when impacted either shatters, showering the operator with glass pellets, or crazes, thereby obscuring the operator's vision. Consequently, while there are definite safety advantages to the use of windshield wipers, it is our view that they do not offset the dangers cited above. Your petition, therefore, is denied.

We trust you will be able to find a laminated glass or acrylic which meets both your requirements and our standard, and wish you success in this endeavor.

Sincerely,

ATTACH.

March 10, 1975

Guy Hunter -- Safety Standard Engineer, National Highway Safety Traffic Administration

Re: Petition for Approval of Tempered Glass for Motorcycle Windscreens

Dear Mr. Hunter:

Thank you for your offer of prompt evaluation and assistance. I do hope, based on the overall improvement in safety for the motorcycle rider, you will permit the use of tempered glass in a motorcycle windscreen. My conversations with suppliers of laminated and tempered glass have convinced me tempered glass is probably the best product available for our needs. It apparently will take a great deal of physical abuse, has good transparency, and will tolerate the action of a windshield washer and wiper without undue scratching.

During our phone conversation, you mentioned the energy absorbing characteristic of laminated glass is the main reason it is exclusively specified for the windshields of closed vehicles. On a motorcycle, a windscreen made of acrylic, polycarbonate, or tempered glass can be fastened to the supporting fairing with breakable nylon bolts. The largest fairing manufacturer, Vetter, emphasises this safety feature. All their acrylic windscreens are fastened with nylon bolts which will break if a rider is thrown forward and impacts heavily against the windscreen. My windscreens will all be fastened with identical or comparable nylon bolts.

Please send me a letter giving me approval, at least on an interim experimental basis, to use tempered glass. Also, please initiate action which will hopefully result in formal approval of tempered glass under Code 205 and ANS Z 26.

Very truly yours,

John S. Hickman, President -- HICKMAN HAMPEL CORP.