Interpretation ID: nht87-3.30

TYPE: INTERPRETATION-NHTSA

DATE: 11/19/87

FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA

TO: M.B. Mathieson -- Director of Engineering, Thomas Built Buses L.P.

TITLE: FMVSS INTERPRETATION

ATTACHMT: 3/20/87 letter from Erika Z. Jones to M.B. Mathieson (Std. 301)

TEXT: Mr. M.B. Mathieson Director of Engineering Thomas Built Buses L.P. P.O. Box 2450 High Point, NC 27261

Dear Mr. Mathieson:

This is in reply to your letter of April 27, 1987, asking for a clarification of my letter of March 20.

In that letter I answered your question as to whether the results of frontal barrier impact tests that occurred at 30.1 mph with a vehicle that exceeded the test height limits would constitute either a noncompliance with Standard No. 301 or a safety rela ted defect. Because the test has not conducted in accordance with Standard No. 301's conditions I replied that this would not be a noncompliance, and further, that those results "do not constitute a safety related defect regardless of the use of the vehi cle." This statement appears unclear to you.

By my earlier statement I intended to explain that we do not use a safety standard's compliance test results (particularly if the test was not conducted in accordance with the prescribed procedures) as the sole basis for a determination of a safety-relat ed defect in the same aspect of performance governed by that standard. For example, having determined through rulemaking that a particular level of vehicle performance is expected in a 30 mph crash test, it would be inappropriate to use the results from an otherwise identical crash test conducted at 35 mph to form the sole basis for a determination of a safety-related defect in the tested vehicles. To do so would constitute, in effect, rulemaking to raise the impact speed in the standard to 35 mph. We c ompletely agree, however, with your statement that "there can be safety-related defects that are not addressed by the standards." We also agree that the manufacturer has the responsibility to address safety defects that become apparent to him through test data or otherwise.

With this background, we will turn to your question. You have now posed a hypothetical in which your tests indicate that a fully-loaded school bus may encounter a severe leakage exceeding 4.1 ounces of fuel per minute in a head-on impact of 30 m.p.h. Thi s may be evidence that could lead you to believe that there would be a significant number of failures if a school bus, in its normal operation with full complement of students, encounters a head-on collision at what appears to be a reasonable operating s peed. This combination of factors might appear to pose an unreasonable risk to safety and afford the basis for the determination that a safety related defect exists.

Sincerely,

Erika Z. Jones Chief Counsel

April 27, 1987

Ms. Erika Z. Jones, Chief Counsel, National Highway Traffic Safety Administration 400 Seventh St., S.W. Washington, D.C. 20590

Dear. Ms. Jones,

This letter is in reference to yours of March 20, 1987, regarding Thomas Built Buses, L.P. questions resulting from crash tests performed on a proposed vehicle utilizing a Thomas school bus body and a Chevrolet Model #G31303 chassis.

We understand from your letter that since the test parameters of vehicle velocity and vehicle test weight did not meet the "letter of the law" in that the test impact velocity exceeded 30 mph by 1.333%, and the vehicle test weight exceeded the manufactur ers limits as defined in @7.1.6(b) of FMVSS 301, that your office has found the test to be invalid as far as determining the requirements of compliance to the standard are concerned.

We further understand from your letter that final stage manufacturers are not prohibited from manufacturing a vehicle that falls outside the limits of the chassis manufacturer's guidelines for maximum unloaded vehicle weight. However, those final stage m anufacturers who build and offer for sale such a vehicle bear full responsibility for certification to FMVSS 301 for such completed vehicles.

We do not understand the basis of the statement in your letter, i.e. "Further, those results do not constitute a safety related defect regardless of the use of vehicle".

Our interpretation of P.L.8g-563 regarding "failure to comply" and "safety related defects" is that these two possible situations are not necessarily coincident or correlated. In other words, while "failure to comply" will possibly always be considered a safety related defect, there can be safety related defects that are not addressed by the Standards but which carry the full responsibility and associated penalties for report and failure to report when they have become apparent to a vehicle manufacturer .

April 24, 1987 Ms. Erika Z. Jones

In light of the above, we would appreciate your consideration of the following:

Thomas Built Buses, L.P., is contemplating the manufacture of a school bus in the "10,000 lbs. or less" GVWR class. We expect the vehicle to operate frequently at the maximum design GVWR of 10,000 lbs., carrying school children in the normal fulfillment of its' purpose. Our tests have indicated that if this fully and legally loaded vehicle encounters a severe head-on impact of 30 mph there will be a significant fuel system "failure" resulting in a fuel leak exceeding 4.1 ounces of fuel per minute.

Question: Does this condition constitute a safety defect in a school bus completed and offered for sale by Thomas Built Buses, L.P.? Thomas Built Buses currently has two prototype vehicles operating in public service.

Your prompt reply would be most helpful to this Company. Sincerely yours,

THOMAS BUILT BUSES, L.P.

M. B. MATHIESON, Director of Engineering

MBM/jm

cc: J. W. Thomas, Jr. J. E. Thomas Roger Chilton Morris Adams Roddey Ligon Tom Mitchell Dale Guthrie