ID: nht93-3.45

DATE: May 17, 1993

FROM: John Womack -- Acting Chief Counsel, U.S. Department of Transportation, NHTSA (Signature by Stephen P. Wood)

TO: St. F. Steiner -- Consultant, AET Network

TITLE: None

ATTACHMT: Attached to letter dated 5-4-93 from St. F. Steiner to John Womack (OCC 8626)

TEXT: We have received your "Dear Mr. Van Orden" letter of May 4, 1993, which was addressed to me. You wish to import 3- and 4- wheeled vehicles from Europe "for research and exploration", and have asked several questions relating to U.S. laws and D.O.T. requirements.

Your first question is: "Are there any safety standards and regulations for the above mentioned automobiles?"

The answer is yes. All 3-wheeled motor vehicles are considered "motorcycles" for purposes of compliance with the Federal motor vehicle safety standards that apply to motorcycles. Depending upon their configuration, but not upon their weight, 4-wheeled vehicles are either "passenger cars", "multipurpose passenger vehicles", "trucks", or "buses" for purposes of the safety standards.

However, motor vehicles intended solely for purposes of research may be imported without the necessity of conforming them to the safety standards under the terms and conditions that the agency has set out in 49 CFR Part 591.

Your second and third questions are whether there is a minimum speed standard regulation or weight limitations for the vehicles you wish to import. The answer is no. However, a motorcycle with 5-horsepower or less is considered a "motordriven cycle", and some of the motorcycle standards impose lesser requirements for motor-driven cycles, and motor-driven cycles whose speed attainable in 1 mile is 30 mph or less.

Your fourth question relates to the conversions required to meet U.S. specifications and standards. As indicated previously, no conversion is required when the importation is solely for the purpose of research. If you wish to import vehicles that have been originally manufactured to meet the Federal motor vehicle safety, bumper, and theft prevention standards, the manufacturer will find those standards at 49 CFR Parts 571, 581, and 541, respectively. If you wish to import nonconforming vehicles for conversion after importation, then the agency must determine that the vehicles are eligible for entry pursuant to 49 CFR Part 593, and importation and conversion accomplished through a Registered Importer pursuant to 49 CFR Part 592.

Your final question is whether the vehicles will be permitted on highways. This is a question that is not answerable under Federal law. Each State determines the criteria for licensing motor vehicles for use on the roads under its jurisdiction. If a State does not license a vehicle for on-road use (all terrain vehicles, minibikes, golf carts are examples), a basis exists for a manufacturer to determine that its vehicles are not "motor vehicles." If a vehicle is not a motor vehicle, i.e. one manufactured primarily for on-road use, then no Federal safety standards apply to it.

If you have any further questions about the importation process, you should refer them to Mr. Van Orden at our Office of Vehicle Safety Compliance, Office of Enforcement.

ID: 8626

St. F. Steiner
Consultant
AET Network
2190 3rd Street
San Francisco, CA 94107

Dear Sir or Madam:

We have received your "Dear Mr. Van Orden" letter of May 4, 1993, which was addressed to me. You wish to import 3- and 4- wheeled vehicles from Europe "for research and exploration", and have asked several questions relating to U.S. laws and D.O.T. requirements.

Your first question is: "Are there any safety standards and regulations for the above mentioned automobiles?"

The answer is yes. All 3-wheeled motor vehicles are considered "motorcycles" for purposes of compliance with the Federal motor vehicle safety standards that apply to motorcycles. Depending upon their configuration, but not upon their weight, 4-wheeled vehicles are either "passenger cars", "multipurpose passenger vehicles", "trucks", or "buses" for purposes of the safety standards.

However, motor vehicles intended solely for purposes of research may be imported without the necessity of conforming them to the safety standards under the terms and conditions that the agency has set out in 49 CFR Part 591.

Your second and third questions are whether there is a minimum speed standard regulation or weight limitations for the vehicles you wish to import. The answer is no. However, a motorcycle with 5-horsepower or less is considered a "motor- driven cycle", and some of the motorcycle standards impose lesser requirements for motor-driven cycles, and motor-driven cycles whose speed attainable in l mile is 30 mph or less.

Your fourth question relates to the conversions required to meet U.S. specifications and standards. As indicated previously, no conversion is required when the importation is solely for the purpose of research. If you wish to import vehicles that have been originally manufactured to meet the Federal motor vehicle safety, bumper, and theft prevention standards, the manufacturer will find those standards at 49 CFR Parts 571, 581, and 541, respectively. If you wish to import nonconforming vehicles for conversion after importation, then the agency must determine that the vehicles are eligible for entry pursuant to 49 CFR Part 593, and importation and conversion accomplished through a Registered Importer pursuant to 49 CFR Part 592.

Your final question is whether the vehicles will be permitted on highways. This is a question that is not answerable under Federal law. Each State determines the criteria for licensing motor vehicles for use on the roads under its jurisdiction. If a State does not license a vehicle for on-road use (all terrain vehicles, minibikes, golf carts are examples), a basis exists for a manufacturer to determine that its vehicles are not "motor vehicles." If a vehicle is not a motor vehicle, i.e. one manufactured primarily for on-road use, then no Federal safety standards apply to it.

If you have any further questions about the importation process, you should refer them to Mr. Van Orden at our Office of Vehicle Safety Compliance, Office of Enforcement.

Sincerely,

John Womack Acting Chief Counsel

ref:591 d:5/17/93

ID: nht92-6.32

DATE: May 27, 1992

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA

TO: Timothy C. Murphy -- Chairman, TSEI Engineering Committee (Lights), Transportation Safety Equipment Institute

TITLE: None

ATTACHMT: Attached to letter dated 4/30/92 from Timothy C. Murphy to Paul J. Rice (OCC 7252)

TEXT:

This responds to your letter of April 30, 1992, requesting an interpretation of Motor Vehicle Safety Standard No. 108. You have asked "whether the lens leg of various lamp assemblies may be included in the calculation" of the minimum effective projected luminous lens area required of certain lamps by Standard No. 108.

Specifically, you have enclosed "Figure 1" which "shows that the last optic against the lens leg projects light outward beyond the lens leg and yet the light may be beneficial to meeting the twenty degree outward test points for stop, tail, turn lamps." Accordingly you have concluded "that this light, though low in intensity due to its distance from the filament, may be significant as far as meeting the photometric requirements of the lamp."

NHTSA adopted a definition of "effective projected luminous lens area" on May 15, 1990 (55 FR 20158), to mean "that area of the projection on a plane perpendicular to the lamp axis of that portion of the light-emitting surface that directs light to the photometric test pattern. . . ." No exceptions were made to the definition. In rejecting a petition for reconsideration to include lens parts, such as the rim (or leg), in the calculation of lens area in those instances where the rim transmits unobstructed light, NHTSA explained on December 5, 1990 (55 FR 50182), that areas that do not contribute "significantly" to light output should not be included in the lens area calculation. It commented that "the optical parts of the reflector and lens are designed to achieve that purpose", and that "lens rims or legs do not contribute to the optical design" but instead "take up surface area that can reduce the area of the optically designed part of the lens if they are allowed to be included in the computation of minimum lens area."

In the comments that both you and we have quoted above, NHTSA has tried to differentiate between optical parts that are specifically designed to contribute to the optical design of a lamp and those whose contribution is only incidental and secondary. Those comments express clearly the agency's opinion that a lens leg, such as shown in your Figure 1, is an optical part that contributes only incidentally to the optical design of a lamp. However, the agency's opinions, as expressed in the preambles on this subject, are not the most definitive answer to your question. Instead, with reference to Figure 1, whether the additional lens area may be included in the computation of the minimum effective projected luminous lens area is determined by the definition of that term set forth in S4 of Standard No. 108. If the lens leg in Figure 1 meets that definition, it may be included in the computation. If not, it may not be included in the computation.

ID: nht92-1.48

DATE: 12/01/92

FROM: PAUL JACKSON RICE -- CHIEF COUNSEL, NHTSA

TO: T. KOUCHI -- DIRECTOR & GENERAL MANAGER, AUTOMOTIVE EQUIPMENT, DEVELOPMENT & ADMINISTRATION DEPT., STANLEY ELECTRIC CO. LTD.

ATTACHMT: ATTACHED TO LETTER DATED 10-8-92 FROM T. KOUCHI TO PAUL J. RICE (OCC 7857)

TEXT: This responds to your letter of October 8, 1992, with respect to photometric test methods for a center high-mounted stop lamp using light emitting diodes (LEDs) as light sources.

Your letter presents certain procedures and asks for associated revisions in Federal Motor Vehicle Safety Standard No. 108. After review, we have come to the conclusion that your method of proposed testing is allowable under Standard No. 108, but more stringent than what the standard requires.

In the section of your letter called "BACKGROUND", you state that you usually follow the technical guidance of SAE J1889 as a standard practice for LED lighting devices. There is no requirement in Standard No. 108 or in any of the SAE standards incorporated by reference in Standard No. 108 that requires you to follow the test methodology of J1889. Thus, when you say that you "must always allow a margin of the same percentage when designing initial light output of the lamp, which necessitates increase in the number of LEDs used, lamp size, product cost, and, therefore, user's expense", you are placing a burden upon yourself that does exist under J1889, but one which is not necessary for designing for compliance with Standard No. 108.

You have proposed a solution for the problem you have created by following J1889, and you provide three specific reasons in support. The third reason is based upon your interpretation of SAE J575's warpage test, under which you test operating cycles of 5 minutes on and 5 minutes off. However, you reference a version of J575 which does not apply to center high-mounted stop lamps. Paragraph S6.1 of Standard No. 108 specifies that J575e, August 1970, applies to high-mounted stop lamps designed to conform to SAE Recommended Practice J186a. SAE J575, August 1970, simply specifies that the device is to be operated in the test in the same manner as it will be operated in service, far different than the cycle method you employ.

Thus, you have requested that we revise Standard No. 108 by adding a new provision that center high-mounted stop lamps shall be energized for a minimum of 5 minutes before measurement of photometric minima. We note that nothing prohibits you from testing in such a manner, but we believe that an amendment of this nature is not required because the present allowable method of testing does not call for it.

You have asked for our comments on four steps of photometric measurement, and our permission to follow them. There is no reason you may not follow them, if you wish, but they are unnecessary to design for compliance under Standard No. 108.

I hope that this is responsive to your questions.

ID: nht91-6.36

DATE: October 23, 1991

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA

TO: Al Lipinski -- President, Mini-Max

TITLE: None

ATTACHMT: Attached to letter dated 9-18-91 from Al Lipinski to Messrs. Hall, Jackson, and Rice, NHTSA (OCC 6509)

TEXT:

This responds to your letter asking what the dynamic testing requirements are for alterers of certified vehicles. You stated that you are a small conversion company of walk in van type light trucks, that you do not alter anything forward of the B pillar of the previously certified vehicle, and that the crash protection system installed by the original manufacturer is not disturbed. You also stated that you affix an additional label stating the vehicle alterations conform to all applicable Federal motor vehicle safety standards.

I am pleased to have this opportunity to explain our regulations to you. Some background information on Federal motor vehicle safety laws and regulations may be helpful. As you are aware, our agency is authorized, under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. S1381 et seq.; Safety Act), to issue safety standards applicable to new motor vehicles and certain items of motor vehicle equipment. NHTSA, however does not approve motor vehicles or motor vehicle equipment, nor do we endorse any commercial products. Instead, the Safety Act establishes a "self-certification" process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards.

Under NHTSA's certification regulation, an alterer is a person who alters previously certified vehicles by means other than the addition, substitution, or removal of readily attachable components, or minor finishing operations, or in such a manner that the vehicle's stated weight ratings are no longer valid, before the first purchase of the vehicle in good faith for purposes other than resale. An alterer is required to certify that every vehicle it alters continues to comply with all applicable safety standards after the alterer has performed its operations on the vehicle. See 49 CFR Part 567.7.

Alterers must have some independent basis for their certification that an altered vehicle continues to comply with all applicable safety standards. This does not, however, mean that an alterer must conduct crash testing, even with respect to standards that include dynamic test requirements. Certifications of continuing compliance for altered vehicles may be based on, among other things, engineering analyses, computer simulations, actual testing, or instructions for alteration voluntarily provided by the original vehicle manufacturer in a "body builder's guide."

Your letter suggests that you are primarily concerned about the dynamic test requirements of Standard No. 208 Occupant Crash Protection. I note that in establishing that standard's dynamic test requirements for light trucks, NHTSA made those requirements optional for walk in van type trucks. See S4.2.2 of Standard No. 208. Thus, the walk in van type

trucks you alter were not required to comply with the Standard No. 208's dynamic test requirements and may not have been designed to do so. You can find out by contacting the original vehicle manufacturer.

I hope this information is helpful.

ID: aiam5082

"Dear Mr. Gould: This responds to your letter asking about th dynamometer requirements of Federal Motor Vehicle Safety Standard No. 121, Air Brake Systems (49 CFR 571.121). You requested clarification of the term 'average deceleration rate' and its tolerance, particularly with respect to the brake power test (S5.4.2). You stated that you view the specified deceleration rate as 'only a target' in order to fade the linings, and believe that it is acceptable to conduct tests at five percent below the specified rate. I am pleased to have this opportunity to explain our regulations to you. Some background information on Federal motor vehicle safety laws and regulations may be helpful. The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq., Safety Act) authorizes this agency to issue safety standards applicable to new motor vehicles and items of motor vehicle equipment. NHTSA, however, does not approve motor vehicles or motor vehicle equipment, nor do we endorse any commercial products. Instead, the Safety Act establishes a 'self-certification' process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. Manufacturers must have some independent basis for their certification that a product complies with all applicable safety standards. This does not necessarily mean that a manufacturer must conduct the specific tests set forth in an applicable standard. Certifications may be based on, among other things, engineering analyses, actual testing, and computer simulations. Whatever the basis for certification, however, the manufacturer must certify that the product complies with a standard as it is written, i.e., that the vehicle will pass all applicable requirements if it is tested exactly according to the standard's test conditions and other specifications. Standard No. 121's dynamometer test requirements are set forth in section S5.4. That section specifies that brake assemblies must meet the requirements of S5.4.1 (brake retardation force- -relevant only to towed vehicles), S5.4.2 (brake power), and S5.4.3 (brake recovery), under the conditions of S6.2. The purpose of the dynamometer test requirements is to help ensure that brakes retain adequate stopping capacity during and after exposure to conditions caused by prolonged or severe use, such as long, downhill driving. With respect to your question about the meaning of 'average deceleration rate,' that term is used in both S5.4.2 and S5.4.3. Section S5.4.2 specifies, for example, that each brake shall be capable of making 10 consecutive decelerations at an average rate of 9 f.p.s.p.s. from 50 mph to 15 mph, and shall be capable of decelerating to a stop from 20 mph at an average deceleration rate of 14 f.p.s.p.s. after the 10th deceleration. In S5.4, the meaning of average deceleration rate is explained as follows: For purposes of the requirements of S5.4.2 and S5.4.3, an average deceleration rate is the change in velocity divided by the decleration time measured from the onset of deceleration. We do not agree with your suggestion that the deceleration rates specified in Standard No. 121 are 'only a target' in order to fade the linings. As indicated above, manufacturers must certify that each vehicle complies with a standard as it is written, i.e., that the vehicle will pass all applicable requirements if it is tested exactly according to the standard's test conditions and other specifications. Thus, if a vehicle was unable to pass Standard No. 121's test requirements at the specified deceleration rates, it would not comply with the standard, notwithstanding the fact that it might be able to pass the standard's requirements at slightly lower deceleration rates. We recognize, however, that it may be difficult to achieve any exact deceleration rate in conducting a brake test. For this reason, the agency's Office of Vehicle Safety Compliance (OVSC) specifies tolerances in its Laboratory Test Procedures developed for use by contractors in conducting compliance tests for the agency. For the brake power and brake recovery tests (S5.4.2 and S5.4.3), the agency's current Laboratory Test Procedure specifies the following tolerances on deceleration rates: +0 to -1 ft/s/s, except for 12 ft/s/s: +0.5 ft/s/s. Enclosed for your information is a copy of the agency's Laboratory Test Procedure for Standard No. 121's dynamometer tests. On the issue of tolerances, I call your attention to the following statement at the beginning of the Laboratory Test Procedure: The OVSC Laboratory Test Procedures, prepared for use by independent laboratories under contract to conduct compliance tests for the OVSC, are not intended to limit the requirements of the applicable FMVSS(s). In some cases, the OVSC Laboratory Test Procedures do not include all of the various FMVSS minimum performance requirements. Sometimes, recognizing applicable test tolerances, the Test Procedures specify test conditions which are less severe than the minimum requirements of the standards themselves. Therefore, compliance of a vehicle or item of motor vehicle equipment is not necessarily guaranteed if the manufacturer limits certification tests to those described in the OVSC Laboratory Test Procedures. If you have any further questions, please feel free to call Mr. Marvin Shaw of my staff at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosure";

ID: aiam4900

Dear Mr. Johannessen: This responds to your letter seeking a interpretation of Standard No. 209, Seat Belt Assemblies (49 CFR 571.209). More specifically, you asked about the meaning of the requirement in S4.1(b) of Standard No. 209 that '...the pelvic restraint shall be designed to remain on the pelvis under all conditions, including collision or roll-over of a motor vehicle.' I am pleased to have this opportunity to explain this provision. You explained that some have asserted that a safety belt fails to comply with S4.1(b) if it actually moves off an occupant's pelvis during a crash. To reach such a conclusion, one must ignore the words 'be designed to' and treat the requirement as though it read '...the pelvic restraint shall remain on the pelvis under all conditions, including collision or roll-over of a motor vehicle.' Such a reading is plainly incorrect, because it reads the phrase 'be designed to' out of the regulation. You explained that you believe S4.1(b) of Standard No. 209 is merely a hortatory phrase that is essentially meaningless. According to your letter, this language first appeared in a standard developed by the Society of Automotive Engineers (SAE), and was subsequently adopted verbatim in the safety belt standard issued bye the Department of Commerce and in Standard No. 209. You asserted that the SAE committee that developed this language included it as a design goal only, since the committee members 'were aware that they had no objective test procedure to confirm compliance with this design goal,' and 'were aware that the seat belt would not necessarily remain on the pelvis during the entire collision event in all of the varied collisions encountered in the field.' We cannot agree with your suggestion that S4.1(b) of Standard No. 209 is merely a hortatory design goal. The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq.) requires each safety standard to meet certain requirements, including, among other things, that the standard be practicable, meet the need for motor vehicle safety, and be stated in objective terms. When NHTSA adopted Standard No. 209 as one of the initial Federal motor vehicle safety standards, the agency concluded that Standard No. 209, including S4.1(b), met all applicable statutory criteria. It is true that there is no compliance test procedure specifically for S4.1(b) of Standard No. 209. However, the meaning of that provision becomes clear when it is viewed in the context of the occupant protection requirements in Standard Nos. 208, Occupant Crash Protection, Standard No. 210, Seat Belt Assembly Anchorages, and the rest of Standard No. 209. Standard No. 208 requires, among other things, that vehicles be equipped with safety belts and that the lap belt portions of those belts adjust to fit persons ranging in size from a 6-year-old child to a 95th percentile adult male (See S7.1.1). Standard No. 209 requires that safety belts meet specified strength, durability, and other performance requirements. Standard No. 210 requires that the anchorage holding the safety belt in the vehicle meet stringent strength requirements, so that the belt will remain attached to the vehicle in a crash, and lap belt location requirements (S4.3.1), including a minimum lap belt mounting angle, to reduce the likelihood of occupant submarining, i.e., having the lap belt move off the pelvis. See the detailed discussion of the minimum lap belt mounting angle at 55 FR 17970, at 17974, April 30, 1990. Viewed in this context, we believe that the requirement of S4.1(b) of Standard No. 209 means that safety belts must be designed to be capable of being properly adjusted and positioned on the pelvis of occupants ranging from 6-year-old children to 95th percentile adult males. The belts must also be capable of remaining on the pelvis of such occupant during collision or roll-over. A belt system that was not capable of being positioned on the pelvis and remaining there during crashes would not comply with S4.1(b). Given this meaning and purpose, we offer the following observations. First, the fact that a lap belt moved off the occupant's pelvis during a collision would not of itself show that the lap belt failed to comply with S4.1(b) of Standard No. 209. Compliance with S4.1(b) of Standard No. 209 is determined by the design of the safety belt system, not the performance of individual safety belts while in service. Second, the actual performance of a safety belt in a vehicle (e.g., a lap belt moving off the occupant's pelvis during a crash) could indicate that the lap belt failed to comply with S4.1(b) of Standard No. 209. If the agency had information indicating that a particular belt design was not capable of being properly positioned on the pelvis or not capable of remaining on the occupant's pelvis when installed in particular vehicles in particular crash modes, the agency might well investigate whether that safety belt design complied with S4.1(b). However, NHTSA has no such information about any safety belt systems at this time. Sincerely, Paul Jackson Rice Chief Counsel;

ID: aiam4434

"Dear Mr. Momboisse: Your letter of May 19, 1988, to the Genera Counsel of the Department of Transportation has been forwarded to this Office for reply. You request a waiver 'exempting the Hummer vehicle from the Federal Motor Vehicle Safety Standards (FMVSS) when purchased directly from the manufacturer, AM General Corporation.' This response is based upon the information contained in your letter, and upon information my staff has obtained in telephone conversations with Ed Butkera of AM General Corporation, manufacturer of the Hummer, relating to its compliance with the Federal motor vehicle safety standards, and Gary Runyon of the Border Patrol, relating to the mission of that agency and the role the Hummer plays in it. According to our information, the Hummer is a vehicle which was developed specifically for, manufactured for, and sold exclusively to, the U.S. Army. The Border Patrol has bought Hummers from the Army because of certain features it finds advantageous in its operations, and its expanded missions involving interdiction of drugs. The principal reasons for your request are (1) that the Border Patrol desires to buy Hummers equipped with an assembly line addition (a central tire inflation system) is not incorporated on the Hummers sold to the Army, and (2) that, by buying directly from AM General Corporation, the Border Patrol will save $5,000 per vehicle, as the price of Army Hummers reflects the added expense of amortized development costs. This agency has jurisdiction over 'motor vehicles' as that term is defined by l5 U.S.C. 139l(3). If a vehicle is not a 'motor vehicle,' then the Federal motor vehicle safety standards do not apply to it. The exclusion of military vehicles from applicability of the safety standards in 49 C.F.R. 57l.7(a), which you quoted, is operative only if those vehicles would otherwise be 'motor vehicles' required to comply with the standards. Under l5 U.S.C. 1391(3), a 'motor vehicle' is 'any vehicle driven or drawn by mechanical power manufactured primarily for use on the public streets, roads, and highways....' The agency has interpreted this definition to exclude such vehicles as minibikes, golf carts, all-terrain vehicles, single seat racing cars used on closed courses, airport crash and rescue vehicles, and farm tractors. On the other hand, the agency has included in the definition farm trailers which haul produce over the public roads to processing centers, stock cars modified for racing unless such modifications are so extensive that the vehicle can no longer be licensed for use on the public roads, and vehicles capable of use both on rails and the public roads. You have informed us that the Hummer will 'generally only be used on public highways to travel between stations and assigned duty areas.' However, you have also informed us that this will constitute approximately 30% of its operational time. Were we to consider this factor alone, we could not conclude that the Hummer was not a 'motor vehicle.' However, there are further factors that make the proper classification of the Hummer a close question. The Hummer was developed as a vehicle for military operations and not for civilian applications, its manufacturer does not advertise or sell it for civilian purposes, and its configuration is such that it probably could not be licensed for use on the public roads without modification of some of its original military specifications. Resolution of this question is not necessary since the mission and method of operation of the Border Patrol provide a separate basis for concluding that the Hummers to be purchased by the Border Patrol are not subject to the FMVSS. We understand that one of the missions of the Border Patrol is to act as an agency of national security in protection of the country's borders to ensure that persons and goods enter and exit only through official Customs and Immigration stations, and that this role has become of paramount importance in the 'war against drugs.' In this enforcement effort, the Hummers of necessity carry firearms such as the M-l4 and M-16 rifles which the Army Hummer carries, can be equipped with military communications equipment enabling them to serve as command posts, and carry certain military equipment used for electronic interception and sensing movement. It further appears that in this mission the Border Patrol is not only equipped like a component of the Armed Forces of the United States, but also is trained and functions in many respects that are similar to such a component. Accordingly, for the purposes of applying the exclusionary phrase of 49 CFR 571.7(a), it is appropriate to regard the Border Patrol as being akin to a component of the Armed Forces of the United States. In consideration of the foregoing, the National Highway Traffic Safety Administration has concluded that AM General Corporation will not be in violation of the National Traffic and Motor Vehicle Safety Act if it manufactures and sells Hummers to the Border Patrol for its use as described in your letter. Sincerely, Erika Z. Jones Chief Counsel";

ID: 2705y

Mr. S. Kadoya
Manager
Safety and Technology
Mazda Research and Development
of North America, Inc.
l203 Woodbridge Avenue
Ann Arbor, Michigan 48l05

Dear Mr. Kadoya:

This responds to your request for interpretations of several safety standards and the Bumper Standard, in connection with a planned "active" suspension system. I regret the delay in responding to your letter. Your questions are responded to below.

By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under the statutes administered by this agency, it is the responsibility of the manufacturer to ensure that its vehicles and equipment comply with applicable standards. The following represents our opinion based on the facts provided in your letter.

According to your letter, Mazda is concerned about the protocol of compliance testing of vehicles equipped with an active suspension system. This concern arises because many standards do not specify a suspension height that is to be used during compliance testing. As you noted, this has not been a concern for conventional suspension systems, since they do not provide for variable height.

Mazda's planned active suspension system would be actuated by hydraulic fluid or compressed air, with control pressure being developed by a hydraulic pump or air compressor driven off the engine. Consequently, the active suspension system would be operational only when the vehicle's engine is operating. At vehicle speeds in excess of "z" mph, where z is greater than 35 mph, the suspension height would be lowered by "x" mm from the nominal or design position for vehicle operation. If the engine/vehicle were not used for several consecutive days, pressure in the control system would fall such that the supension height may be lowered from the nominal or design position for vehicle operation by "y" mm, where y is greater than x. The suspension height would return to the nominal or design position for vehicle operation after such an extended period of inoperation almost immediately after starting the vehicle's engine.

Before discussing your specific questions, I would like to discuss more generally the issue of how compliance is determined in situations where a standard does not specify a particular test condition. In issuing Federal motor vehicle safety standards, NHTSA attempts to specify all relevant test conditions. The agency does this as part of ensuring that its standards are objective and practicable. As a practical matter, however, it is not possible to specify every conceivable test condition. This is particularly true for ones which may only be relevant to as-yet-undeveloped technologies.

In cases where a standard does not specify a particular test condition, we believe there are several relevant factors to consider in interpreting the standard. First, in the absence of specification of a particular test condition, we believe there is a presumption that the requirements need to be met regardless of such test condition, since the standard does not include any language which specifically limits applicability of its requirements to such test condition. For example, where a standard does not specify suspension height, its requirements may need to be met at all heights to which the suspension can be adjusted. Before reaching such a conclusion, however, we also consider the language of the standard as a whole and its purposes. Even if a standard is silent as to a particular test condition, the language of the standard or its purposes may indicate limitations on such test condition. Finally, in situations where a limitation on a particular test condition may appear to be appropriate, we also must consider whether the limitation is sufficiently clear, both with respect to justification and specificity, to be appropriate for interpretation. For example, in a situation where it may appear to be reasonable to limit a particular test condition but it is not obvious what particular limitation should be adopted, it would be inappropriate to select a particular limitation by interpretation. Instead, such a decision should be reached in rulemaking.

I will now address the specific questions asked in your letter.

Standard No. l08, Lamps, Reflective Devices, and Associated Equipment

In asking about Standard No. l08, you stated the following:

NHTSA has previously issued an interpretation of the requirements of FMVSS No. l08; at the request of a confidential applicant and dated February l2, l985, with respect to active suspension equipped vehicles. This interpretation stated that the requirements of FMVSS l08 must be meet (sic),"...at any time in which..." lamps, reflective devices, and associated equipment are to be,"...operated for its intended purpose." Consequently, headlamps, tailamps, stoplamps, the license plate lamp, and side marker lamps, must comply with the location requirements of FMVSS No. l08 whenever the vehicle's ignition is in the "on" postiion. Conversely, reflex reflectors, and turn signal lamps that also function as hazard warning signal flashers must comply with the location requirements when the vehicle's ignition is in either the "on" or "off" position. However, it is Mazda's interpretation that hazard warning flashers are not intended to be operational for a period of days, but rather for a period of hours, at maximum, only.

You then asked two questions, (l) whether Mazda's understanding of the subject NHTSA interpretation is accurate, and (2) whether Mazda's interpretation of the maximum intended operating duration of hazard warning signal flashers is correct.

I note that the February l985 interpretation was written in the context of a vehicle with a variable height system actuated by hydraulic fluid. In that particular system, the hydraulic pressure relaxed over a period of about three hours after the ignition was turned off, with the result that the vehicle assumed a lower height than it would have during driving. NHTSA stated the following:

We believe that the minimum height requirement should be met for any lamp at any time in which it is operated for its intended purpose. Since vehicles at rest do not require use of headlamps, the minimum height requirement would be measured at the point after the ignition is on and when the car begins to travel (your letter implies that the time lag between turning on the ignition and restoration of a complying mounting height is a matter of seconds). On the other hand, the hazard warning signal lamps are frequently operated when the vehicle is stopped, and therefore the minimum mounting height of turn signal lamps, through which they operate, must be met with the ignition off, even if the system requires three hours to deplete itself and lower the vehicle to its minimum height.

With respect to your question of whether Mazda's understanding of the interpretation is correct, I would like to note two points. First, while you state that "the requirements of FMVSS l08" must be met at any time in which lamps, reflective devices, and associated equipment are to be operated for their intended purpose, our interpretation was limited to standard's minimum height requirement. While we are prepared, if asked, to address other requirements, our interpretations should be understood to be limited to their specific facts and conclusions. Second, while our interpretation only addressed headlamps and hazard warning signal lamps, you applied the interpretation for headlamps to taillamps, stoplamps, the license plate lamp, and side marker lamps, and the interpretation for hazard warning signal lamps to reflex reflectors. We concur with this application, with respect to Standard No. l08's minimum height requirement.

We do not agree with Mazda's suggested interpretation of the maximum intended operating duration of hazard warning signal flashers. You would apparently like us to conclude that Standard No. l08's minimum height requirement for hazard warning signal flashers does not apply after a vehicle's ignition has been turned off for a matter of days.

In addressing how Standard No. l08 applies in the absence of a specification for vehicle height, our February l985 interpretation differentiates between situations where the vehicle is operating and where it is not. Looking at the purposes of the requirements in question, we believe it is obvious that the minimum height requirement for headlamps is only relevant in situations where the vehicle is operating, while the minimum height for hazard warning signal lamps is also relevant to situations where the vehicle is stopped and the ignition turned off. However, we believe that any determination that Standard No. l08's minimum height requirement for hazard warning signal flashers should not apply after a specified number of hours after the ignition has been turned off is one that would need to be addressed in rulemaking.

It is therefore my opinion that the minimum mounting height of hazard warning signal lamps must be met at all heights with the ignition off, even if the system requires days to deplete itself and lower the vehicle to its minimum height. If you believe that a time limitation should be placed on this requirement, I note that you can submit a petition for rulemaking requesting such a change.

Standard No. lll, Rearview Mirrors

You requested an interpretation of section S5.l.l of Standard No. lll, which generally requires a passenger car's rearview mirror to "provide a field of view with an included horizontal angle measured from the projected eye point of at least 20 degrees, and sufficient angle to provide a view of level road surface extending to the horizon beginning at a point not greater than 200 feet to the rear of the vehicle...." You noted that since the specified procedures for determining the location of the driver's eye reference points are made referenced to points with the vehicle's cabin, your active suspension system would not affect these measurements. However, different vehicle heights would be relevant to whether there is a view of level road surface extending to the horizon beginning at a point not greater than 200 feet to the rear of the vehicle. You stated that, based on "intended purpose," Mazda's interpretation of Standard No. lll is that the requirements of this standard are to be met when the vehicle's ignition is in the "on" position as rearview mirrors are not intended to be used when the vehicle's engine is not operating.

You then asked two questions, (l) whether Mazda's interpretation of the requirements of FMVSS No. lll with respect to the state of the vehicle's ignition switch is correct, and (2) for the purposes of compliance testing to the requirements of FMVSS No. lll, what means of maintaining the intended suspension height for a given speed and operating condition would be satisfactory to NHTSA.

We agree that the field of view requirement specified in S5.l.l for rearview mirrors need not be met for vehicle heights that only occur when the engine is not on, since the requirement is only relevant in situations where the vehicle is operating. However, the requirement would need to be at all vehicle heights that occur during vehicle operation, under the loading conditions specified in S5.l.l.

With respect to the issue of how suspension height should be maintained for purposes of compliance testing, you note early in your letter that, for reasons of practicality and safety, a vehicle's engine is not actually operational during compliance testing. However, since the active suspension system derives its power from the vehicle's engine, the system's ability to maintain and regulate suspension height is only possible during engine operation. You therefore indicated that Mazda is seeking guidelines (for several standards) by which Mazda may be able to establish a means to maintain the intended suspension height for compliance testing purposes in the absence of engine operation.

We are not able, in an interpretation, to specify a particular means for maintaining suspension height for compliance testing in the absence of engine operation. However, the basic principle that should be followed in selecting a means for maintaining suspension height is that it should not result in different test results than would occur if testing could be conducted with suspension height being maintained by engine operation, i.e., what would happen in the real world. This should be relatively straightforward for section S5.l.l of Standard No. lll, since the test is static. For a crash test, it is important that a vehicle not be altered in any way that would change the vehicle's crash performance relevant to the aspect of performance being tested.

Standard No. 204, Steering Control Rearward Displacement

In asking about Standard No. 204, you stated the following:

Section S4 of this standard specifies the compliance parameter for this standard. Section S5 specifies the testing conditions to determine compliance with this standard. Section S5.l specifies that the vehicle be loaded to its unloaded vehicle weight. Section S5.5 specifies that the vehicles fuel tank be filled with Stoddard solvent to any capacity between 90 and 95 percent of the total capacity of the tank. Mazda's interpretation of the requirements of this standard is that they are to be met when the vehicle's ignition switch is in the "on" position only. Furthermore, Mazda interprets the vehicles suspension height pursuant to S5.l and S5.5 to be the intended suspension height for the vehicle given the conditions of S4, i.e., 30 mph vehicle speed and steered wheels are positioned straight ahead.

You then asked whether Mazda's interpretation of the requirements of FMVSS No. 204 are correct. As discussed below, we agree that Standard No. 204's requirements need to be met only at the suspension height that occurs at a 30 mph vehicle speed and with steered wheels positioned straight ahead.

Standard No. 204 specifies requirements limiting the rearward displacement of the steering control into the passenger compartment to reduce the likelihood of chest, neck, or head injury. These requirements must be met in a 30 mile per hour perpendicular impact into a fixed collision barrier. While the standard specifies a number of test conditions, it does not specify suspension height.

Looking at the Standard No. 204 as a whole, we believe it is clear that NHTSA explicitly decided to limit the standard's evaluation of steering control rearward displacement to how vehicles perform in 30 mph perpendicular impacts, even though the requirements have relevance at lower and higher speeds. Therefore, we agree that the standard's requirements need to be met only at suspension heights that occur at a 30 mph vehicle speed and with steered wheels positioned straight ahead.

With respect to Mazda's question concerning means of maintaining intended suspension height for compliance testing, please see our discussion provided with respect to Standard No. lll.

Standard No. 208, Occupant Crash Protection

In asking about Standard No. 208, you stated the following:

Section S8.l.l(d), "Vehicle test attitude," specifies the procedure for determining the vehicle test attitude that is to be used for testing. Specifically, this section requires that the vehicle's pretest attitude, "...shall be equal to either the as delivered or fully loaded attitude or between the as delivered and fully loaded attitude." The as delivered attitude is defined by S8.l.l(d) as being, "...the distance between a level surface and a standard reference point on the test vehicle's body, directly above each wheel opening, when the vehicle is in its "as delivered" condition. The "as delivered" condition is the vehicle as received at the test site..." Because it is highly likely that the test vehicle will not have been operated for a period of days prior to arriving at the test site, the suspension height may have fallen by "y" mm. The fully loaded attitude is defined as the attitude of the vehicle when loaded in accordance with S8.l.l(a) or (b) and a determination of the height of the suspension at the fully loaded condition is made from the same level surface, using the same standard reference points, as were used to determine the "as delivered" condition. The definition of the "as delivered" condition is quite clear. However, Mazda interprets the "fully loaded condition" of the vehicle to be the condition when the vehicle's ignition is "on." In this instance it is likely that the height of the standard reference points on the vehicles body when in the "fully loaded condition" relative to the level surface will be greater than for the "as delivered" condition. Conversely, conventional vehicle suspension systems will likely have an "as delivered" height greater than the "full loaded" height. However, this fact is of no importance as S8.l.l(d) states that the pretest vehicle attitude may be, "...between the as delivered and the fully loaded attitude." With respect to the injury criteria specified by section S6 of this standard, Mazda's interpretation is that these criteria must be met with the vehicle's ignition in the "on" position only.

You then asked three questions, (l) whether Mazda's interpretation of the definition of the "fully loaded condition" is correct with respect to the condition of the ignition switch, (2) whether Mazda's interpretation of the irrelevance of the relative relationship between the "as delivered" and "fully loaded" conditions is correct, and (3) whether Mazda's interpretation of the meaning of "between the as delivered and the fully loaded attitude" is correct.

In addressing your questions, I will begin by noting that Standard No. 208 specifies occupant protection requirements which must be met in specified crash tests at any impact speed up to and including 30 mph. While the standard specifies a number of test conditions, it does not specify suspension height. However, the standard does specify vehicle attitude, which is closely related to suspension height. In addressing how Standard No. 208 applies in the absence of a specification for vehicle height, the relationship between the standard's attitude specification and vehicle height must be considered.

Section S8.l.l(d) specifies the attitude of the vehicle during testing, i.e., the angle of the vehicle relative to the ground. This test condition ensures that the vehicle is not overly tilted toward the front or back, or to one side. The section accomplishes this purpose by specifying that, during a compliance test, the height of the vehicle at each wheel is within a specified range. This range, which may be somewhat different for each wheel, is determined by looking at the vehicle in the "as delivered" condition and the "fully loaded" condition. A vehicle must meet the requirements of Standard No. 208 when its height at each wheel is anywhere within the specified ranges.

On first glance, one might read section S8.l.l(d) to create a height requirement, since ranges of height are determined under that section (at each wheel). This would be incorrect, except in a very narrow sense, since Standard No. 208 does not specify, for vehicles with variable height suspension systems, what suspension height should be used in the two conditions ("as delivered" and "fully loaded") where the specified ranges of height are determined under section S8.l.l(d).

Looking at the Standard No. 208 as a whole, we believe it is clear that NHTSA explicitly decided to limit the standard's evaluation of occupant crash protection in frontal impacts to how vehicles perform in impacts of 30 mph or less, even though the requirements also have relevance at higher speeds. It is our interpretation that the frontal crash test requirements need to be met at all suspension heights that can occur at speeds of 30 mph or less, with the vehicle operational. It is also our interpretation that the crash test requirements need to be met only at suspension heights that can occur at the speed used in the crash test.

A remaining issue is how section S8.l.l(d) applies for vehicles with variable height suspension systems. As discussed below, vehicle attitude should be determined under this section using the actual suspension setting (or equivalent, if the setting is automatic) to be used in a crash test.

For purposes of illustration, I will assume a vehicle with two very different suspension height settings. It would not be appropriate to conclude that the ranges of height determined under section S8.l.l(d) should simultaneously cover both suspension heights. Such ranges would be very large, and would not ensure that the vehicle is not overly tilted toward the front or back, or to one side. Moreover, such ranges would not be relevant to the real world, with respect to vehicle attitude.

Traditional vehicles can be viewed as having a single suspension "setting." This single suspension condition is used in determining vehicle attitude under section S5.8.8.l. The ranges of height result from the differences in loading under the "as delivered" and "fully loaded" conditions.

A single suspension "setting" (or equivalent, if the setting is automatic) should similarly be used in determining vehicle attitude for vehicles with variable height suspension systems. The "setting" should be the one to be used in a crash test.

With respect to Mazda's question concerning means of maintaining intended suspension height for compliance testing, please see our discussion provided with respect to Standard No. lll.

You also asked for an interpretation of section S8.2.7 of Standard No. 208. That section specifies additional conditions to be used for lateral moving barrier crash testing. Section S8.2.7(a) states that the vehicle is at rest in its "normal attitude." You stated that Mazda interprets the meaning of "normal attitude" to be that vehicle attitude which is intended when the vehicle's ignition is in the "on" condition, with the vehicle loaded pursuant to S8.l.l(a) or (b), and while the vehicle is at rest.

Standard No. 208 provides manufacturers the option of either equipping their vehicles with safety belts or meeting certain alternative requirements, including lateral moving barrier crash test requirements. These requirements are relevant at all vehicle heights that can occur during vehicle operation, regardless of speed. Moreover, NHTSA has not decided to limit the standard's evaluation of this aspect of safety performance to how vehicles perform at certain limited speeds. It is our interpretation that the lateral moving barrier crash test requirements, if applicable, must be met at all suspension heights that can occur with the vehicle operational. "Normal attitude" is the attitude determined under section S8.l.l(d). As discussed above, attitude for vehicles equipped with variable height suspension systems is determined under section S8.l.l(d) using the actual suspension setting (or equivalent, if the setting is automatic) to be used in a crash test. Standards No. 2l2, Windshield Mounting; No. 2l9, Windshield Zone Intrusion; No. 30l, Fuel System Integrity

In asking about Standards No. 2l2, No. 2l9, and No. 30l, you noted that NHTSA has previously issued an interpretation to Mazda about how these standards apply to adjustable height suspension systems. In a letter dated August l0, l982, the agency addressed a vehicle equipped with a suspension system having two height positions, one for normal highway driving and another for off-road driving, which could be selected by the driver. NHTSA stated the following:

[Safety Standards No. 2l2, No. 2l9, and No. 30l] do not specify a height adjustment because almost all vehicles have a single, set adjustment. . . . After careful consideration, it is the agency's position that such a vehicle capable of variable height adjustment would have to comply with the vehicle adjusted to any position that is possible. This is true because the vehicle could be driven on the highway, for example, even if it were adjusted to the off-road position. Consequently, it is important that the vehicle comply with the standards in all positions.

You noted that while suspension height could be adjusted by the driver for the system discussed in the agency's previous interpretation, the active suspension system you are currently considering would use an on-board electronic controller to select suspension height, and suspension height would not be adjustable by the driver. Consequently, according to your letter, only one unique set of suspension height parameters is possible for a given vehicle speed and loading condition as is the case with conventional suspension systems. You stated that because it is possible to determine exactly what the intended suspension height should be for a given situation, it is Mazda's opinion that the test vehicle should be tested at the intended suspension height given the specified speed and loading conditions. You also stated that, using an "intended purpose" argument, Mazda concludes that the requirements of the three standards are to be met only when the vehicle's ignition is "on." You then asked whether these suggested interpretations are correct.

Standard No. 2l2 specifies windshield retention requirements that must be met in a specified frontal crash test at any impact speed up to and including 30 mph. Similarly, Standard No. 2l9 specifies windshield zone intrusion requirements that must be met in a specified frontal crash test at any impact speed up to and including 30 mph. Standard No. 30l specifies fuel system integrity requirements for several specified crash tests. These include a frontal crash test similar to those in Standards No. 2l2 and No. 2l9. Requirements for this test must be met at any impact speed up to and including 30 mph. Other tests include a rear moving barrier crash test, a lateral moving barrier crash test, and a static rollover test.

We agree that the requirements of Standards No. 2l2, No. 2l9, and No. 30l need not be met for vehicle heights that only occur when the engine is not on, since the requirements are only relevant in situations where the vehicle is operating. Looking at the three standards as a whole, we believe it is clear that, for the frontal tests specified by the three standards, NHTSA decided to limit the standards' evaluation of safety performance to how vehicles perform in impacts of 30 mph or less, even though the requirements have relevance at higher speeds. It is our interpretation that the frontal crash test requirements specified by these standards need to be met at all suspension heights that can occur at speeds of 30 mph or less, with the vehicle operational. It is also our interpretation that the crash test requirements need to be met only at suspension heights that can occur at the speed used in the crash test.

We reach a different conclusion for Standard No. 30l's other crash test requirements. These requirements are relevant at all vehicle speeds and suspension heights. Moreover, NHTSA has not decided to limit the standard's evaluation of these aspects of safety performance to how vehicles perform at certain limited speeds. It is our interpretation that these crash test requirements must be met at all suspension heights that can occur with the vehicle operational.

Part 58l Bumper Standard

In asking about the Part 58l Bumper Standard, you noted that NHTSA has previously issued several interpretations of how the standard applies to vehicles with adjustable height suspension systems. In a letter to Subaru dated May 6, l986, NHTSA stated the following:

Given the absence of a specific test condition concerning suspension height, it is our interpretation that a vehicle must be capable of meeting the standard's damage criteria at any height position to which the suspension can be adjusted. There is no language in the test requirements of the standard limiting their applicability to "the manufacturer's nominal design highway adjusted height position."

This interpretation is consistent with the purpose of the Bumper Standard, set forth in section 58l.2, to reduce physical damage to the front and rear ends of a passenger motor vehicle from low speed collisions. If a vehicle's suspension could be adjusted so that its bumper height resulted in bumper mismatch with other vehicles in the event of low speed collisions, the reduction in physical damage attributable to the Bumper Standard would be defeated in whole or part.

In another letter, dated February l2, l985, NHTSA stated that a vehicle is "required to meet the pendulum test of Part 58l in any vehicle use scenario in which the vehicle operates, and the barrier test of Part 58l when the engine is idling."

You suggested, for the barrier test, that the agency's May l986 interpretation may be inappropriate for your active suspension system, since your system provides for only one suspension height when the engine is idling. You also suggested, for the pendulum test, that these interpretations seem to be in conflict with the Bumper Standard's stated purpose to reduce physical damage to motor vehicles in low speed collisions. We assume that you are referring to the fact that your suspension system has heights that occur only at speeds greater than 35 mph. You then requested that NHTSA provide an interpretation of Part 58l with respect to your system.

In addressing how Part 58l applies to vehicles equipped with an active suspension system, I will address separately the standard's barrier and pendulum tests. For the barrier test, a vehicle must meet specified damage criteria after an impact into a fixed barrier that is perpendicular to the line of travel of the vehicle, at 2.5 mph. Section 58l.6 sets forth conditions applicable to bumper testing. Under section 58l.6(c), at the onset of a barrier impact, the vehicle's engine is operating at idling speed.

Looking at the Bumper Standard as a whole, we believe it is clear that NHTSA decided to limit the barrier test's evaluation of bumper performance to how vehicles perform in 2.5 mph frontal impacts, even though the requirements have relevance at lower and higher speeds and when the vehicle is nonoperational. It is our interpretation that the barrier test requirements specified by this standard need to be met at all suspension heights that can occur at 2.5 mph.

We reach a different conclusion for the pendulum test, which serves the purpose of creating a bumper height requirement. This requirement is relevant at all vehicle speeds and suspension heights, and when the vehicle is nonoperational. I note that while Mazda is correct that the Bumper Standard's stated purpose is to reduce physical damage to motor vehicles in low speed collisions, NHTSA has justified the bumper height requirement on safety concerns related to "higher speed collisions." In proposing Standard No. 2l5, the predecessor of Part 58l, the agency stated:

. . . in higher speed collisions the tendency of a bumper to override another or to ride under or over a guardrail creates hazards for vehicle occupants. Vehicles with interlocking bumpers block traffic and expose their occupants to considerable danger, particularly if they attempt to get out to unlock bumpers. By overriding or underriding a guardrail, a bumper may strike a supporting post, or similar fixed object, with serious consequences for the vehicle and its occupants. 35 FR l7999, November 24, l970.

The relevance of the bumper height requirement to nonoperational situations is also clear, e.g., to help protect parked cars.

Moreover, NHTSA has not decided to limit the bumper height requirement to how vehicles perform at certain limited speeds. It is our interpretation that the pendulum test requirements must be met at all suspension heights that can occur, regardless of vehicle speed or whether the ignition is turned on.

This interpretation is consistent with an October l8, l978 letter to Nissan, in which NHTSA addressed how the pendulum test applies to vehicles equipped with height control systems, including automatic height control systems. Among other things, the agency stated the following:

. . . There is no language in the pendulum test requirements of the standard which would limit their applicability to only the ignition-on or ignition-off situation or to the recommended driving position for normal roadways. The vehicle must be capable of meeting the pendulum test requirements at all stable bumper heights possible at unloaded vehicle weight.

Thus, in the situations described in Question l and 2 of your letter, in which an automatic height control system is employed, the vehicle must comply with the pendulum test requirements in both the ignition-on and ignition-off positions . . . .

I note that one of our past letters, a December 24, l984 letter addressed to Porsche, appears to suggest that the pendulum test must be met in any setting in which the system operates "when the engine is idling." This might be read to suggest that the pendulum test need not be met when the vehicle is nonoperational. However, this interpretation cited section 58l.6(c) in concluding that the engine is idling during Part 58l testing. Section 58l.6(c) applies only to the barrier test and not the pendulum test. We therefore consider this interpretation to be incorrect to the extent that it is inconsistent with the analysis presented above.

Sincerely,

Paul Jackson Rice Chief Counsel

ref:l08#lll#204#208#2l2#2l9#30l#58l d:l0/2/90

ID: nht90-4.30

TYPE: Interpretation-NHTSA

DATE: October 2, 1990

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA

TO: S. Kadoya -- Manager, Safety and Technology, Mazda Research and Development of North America, Inc.

TITLE: None

ATTACHMT: Attached to letter dated 11-7-89 from S. Kadoya to S.P. Wood

TEXT:

This responds to your request for interpretations of several safety standards and the Bumper Standard, in connection with a planned "active" suspension system. I regret the delay in responding to your letter. Your questions are responded to below.

By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under the statutes administered by this agency, it is the responsibility of the manufac turer to ensure that its vehicles and equipment comply with applicable standards. The following represents our opinion based on the facts provided in your letter.

According to your letter, Mazda is concerned about the protocol of compliance testing of vehicles equipped with an active suspension system. This concern arises because many standards do not specify a suspension height that is to be used during complianc e testing. As you noted, this has not been a concern for conventional suspension systems, since they do not provide for variable height.

Mazda's planned active suspension system would be actuated by hydraulic fluid or compressed air, with control pressure being developed by a hydraulic pump or air compressor driven off the engine. Consequently, the active suspension system would be opera tional only when the vehicle's engine is operating. At vehicle speeds in excess of "z" mph, where z is greater than 35 mph, the suspension height would be lowered by "x" mm from the nominal or design position for vehicle operation. If the engine/vehicl e were not used for several consecutive days, pressure in the control system would fall such that the supension height may be lowered from the nominal or design position for vehicle operation by "y" mm, where y is greater than x. The suspension height w ould return to the nominal or design position for vehicle operation after such an extended period of inoperation almost immediately after starting the vehicle's engine.

Before discussing your specific questions, I would like to discuss more generally the issue of how compliance is determined in situations where a standard does not specify a particular test condition. In issuing Federal motor vehicle safety standards, N HTSA attempts to specify all relevant test conditions. The agency does this as part of ensuring that its standards are objective and practicable. As a practical matter, however, it is not possible to specify every conceivable test condition. This is p articularly true for ones which may only be relevant to

as-yet-undeveloped technologies.

In cases where a standard does not specify a particular test condition, we believe there are several relevant factors to consider in interpreting the standard. First, in the absence of specification of a particular test condition, we believe there is a presumption that the requirements need to be met regardless of such test condition, since the standard does not include any language which specifically limits applicability of its requirements to such test condition. For example, where a standard does n ot specify suspension height, its requirements may need to be met at all heights to which the suspension can be adjusted. Before reaching such a conclusion, however, we also consider the language of the standard as a whole and its purposes. Even if a s tandard is silent as to a particular test condition, the language of the standard or its purposes may indicate limitations on such test condition. Finally, in situations where a limitation on a particular test condition may appear to be appropriate, we also must consider whether the limitation is sufficiently clear, both with respect to justification and specificity, to be appropriate for interpretation. For example, in a situation where it may appear to be reasonable to limit a particular test condit ion but it is not obvious what particular limitation should be adopted, it would be inappropriate to select a particular limitation by interpretation. Instead, such a decision should be reached in rulemaking.

I will now address the specific questions asked in your letter.

Standard No. 108, Lamps, Reflective Devices, and Associated Equipment

In asking about Standard No. 108, you stated the following:

NHTSA has previously issued an interpretation of the requirements of FMVSS No. 108; at the request of a confidential applicant and dated February 12, 1985, with respect to active suspension equipped vehicles. This interpretation stated that the requirem ents of FMVSS 108 must be meet (sic),"...at any time in which..." lamps, reflective devices, and associated equipment are to be,"...operated for its intended purpose." Consequently, headlamps, tailamps, stoplamps, the license plate lamp, and side marker lamps, must comply with the location requirements of FMVSS No. 108 whenever the vehicle's ignition is in the "on" postiion. Conversely, reflex reflectors, and turn signal lamps that also function as hazard warning signal flashers must comply with the lo cation requirements when the vehicle's ignition is in either the "on" or "off" position. However, it is Mazda's interpretation that hazard warning flashers are not intended to be operational for a period of days, but rather for a period of hours, at max imum, only.

You then asked two questions, (1) whether Mazda's understanding of the subject NHTSA interpretation is accurate, and (2) whether Mazda's interpretation of the maximum intended operating duration of hazard warning signal flashers is correct.

I note that the February 1985 interpretation was written in the context of a vehicle with a variable height system actuated by hydraulic fluid. In that particular system, the hydraulic pressure relaxed over a period of

about three hours after the ignition was turned off, with the result that the vehicle assumed a lower height than it would have during driving. NHTSA stated the following:

We believe that the minimum height requirement should be met for any lamp at any time in which it is operated for its intended purpose. Since vehicles at rest do not require use of headlamps, the minimum height requirement would be measured at the point after the ignition is on and when the car begins to travel (your letter implies that the time lag between turning on the ignition and restoration of a complying mounting height is a matter of seconds). On the other hand, the hazard warning signal lamps are frequently operated when the vehicle is stopped, and therefore the minimum mounting height of turn signal lamps, through which they operate, must be met with the ignition off, even if the system requires three hours to deplete itself and lower the v ehicle to its minimum height.

With respect to your question of whether Mazda's understanding of the interpretation is correct, I would like to note two points. First, while you state that "the requirements of FMVSS 108" must be met at any time in which lamps, reflective devices, and associated equipment are to be operated for their intended purpose, our interpretation was limited to standard's minimum height requirement. While we are prepared, if asked, to address other requirements, our interpretations should be understood to be limited to their specific facts and conclusions. Second, while our interpretation only addressed headlamps and hazard warning signal lamps, you applied the interpretation for headlamps to taillamps, stoplamps, the license plate lamp, and side marker lam ps, and the interpretation for hazard warning signal lamps to reflex reflectors. We concur with this application, with respect to Standard No. 108's minimum height requirement.

We do not agree with Mazda's suggested interpretation of the maximum intended operating duration of hazard warning signal flashers. You would apparently like us to conclude that Standard No. 108's minimum height requirement for hazard warning signal fla shers does not apply after a vehicle's ignition has been turned off for a matter of days.

In addressing how Standard No. 108 applies in the absence of a specification for vehicle height, our February 1985 interpretation differentiates between situations where the vehicle is operating and where it is not. Looking at the purpose of the require ments in question, we believe it is obvious that the minimum height requirement for headlamps is only relevant in situations where the vehicle is operating, while the minimum height for hazard warning signal lamps is also relevant to situations where the vehicle is stopped and the ignition turned off. However, we believe that any determination that Standard No. 108's minimum height requirement for hazard warning signal flashers should not apply after a specified number of hours after the ignition has be en turned off is one that would need to be addressed in rulemaking.

It is therefore my opinion that the minimum mounting height of hazard warning signal lamps must be met at all heights with the ignition off, even if the system requires days to deplete itself and lower the vehicle

to its minimum height. If you believe that a time limitation should be placed on this requirement, I note that you can submit a petition for rulemaking requesting such a change.

Standard No. 111, Rearview Mirrors

You requested an interpretation of section S5.1.1 of Standard No. 111, which generally requires a passenger car's rearview mirror to "provide a field of view with an included horizontal angle measured from the projected eye point of at least 20 degrees, and sufficient angle to provide a view of level road surface extending to the horizon beginning at a point not greater than 200 feet to the rear of the vehicle...." You noted that since the specified procedures for determining the location of the driver 's eye reference points are made referenced to points with the vehicle's cabin, your active suspension system would not affect these measurements. However, different vehicle heights would be relevant to whether there is a view of level road surface exte nding to the horizon beginning at a point not greater than 200 feet to the rear of the vehicle. You stated that, based on "intended purpose," Mazda's interpretation of Standard No. 111 is that the requirements of this standard are to be met when the vehi cle's ignition is in the "on" position as rearview mirrors are not intended to be used when the vehicle's engine is not operating.

You then asked two questions, (1) whether Mazda's interpretation of the requirements of FMVSS No. 111 with respect to the state of the vehicle's ignition switch is correct, and (2) for the purposes of compliance testing to the requirements of FMVSS No. 1 11, what means of maintaining the intended suspension height for a given speed and operating condition would be satisfactory to NHTSA.

We agree that the field of view requirement specified in S5.1.1 for rearview mirrors need not be met for vehicle heights that only occur when the engine is not on, since the requirement is only relevant in situations where the vehicle is operating. Howe ver, the requirement would need to be at all vehicle heights that occur during vehicle operation, under the loading conditions specified in S5.1.1.

With respect to the issue of how suspension height should be maintained for purposes of compliance testing, you note early in your letter that, for reasons of practicality and safety, a vehicle's engine is not actually operational during compliance testi ng. However, since the active suspension system derives its power from the vehicle's engine, the system's ability to maintain and regulate suspension height is only possible during engine operation. You therefore indicated that Mazda is seeking guideli nes (for several standards) by which Mazda may be able to establish a means to maintain the intended suspension height for compliance testing purposes in the absence of engine operation.

We are not able, in an interpretation, to specify a particular means for maintaining suspension height for compliance testing in the absence of engine operation. However, the basic principle that should be followed in selecting a means for maintaining s uspension height is that it should not result in different test results than would occur if testing could be conducted with suspension height being maintained by engine operation,

i.e., what would happen in the real world. This should be relatively straightforward for section S5.1.1 of Standard No. 111, since the test is static. For a crash test, it is important that a vehicle not be altered in any way that would change the vehi cle's crash performance relevant to the aspect of performance being tested.

Standard No. 204, Steering Control Rearward Displacement

In asking about Standard No. 204, you stated the following:

Section S4 of this standard specifies the compliance parameter for this standard. Section S5 specifies the testing conditions to determine compliance with this standard. Section S5.1 specifies that the vehicle be loaded to its unloaded vehicle weight. Section S5.5 specifies that the vehicles fuel tank be filled with Stoddard solvent to any capacity between 90 and 95 percent of the total capacity of the tank. Mazda's interpretation of the requirements of this standard is that they are to be met when the vehicle's ignition switch is in the "on" position only. Furthermore, Mazda interprets the vehicles suspension height pursuant to S5.1 and S5.5 to be the intended suspension height for the vehicle given the conditions of S4, i.e., 30 mph vehicle speed and steered wheels are positioned straight ahead.

You then asked whether Mazda's interpretation of the requirements of FMVSS No. 204 are correct. As discussed below, we agree that Standard No. 204's requirements need to be met only at the suspension height that occurs at a 30 mph vehicle speed and with steered wheels positioned straight ahead.

Standard No. 204 specifies requirements limiting the rearward displacement of the steering control into the passenger compartment to reduce the likelihood of chest, neck, or head injury. These requirements must be met in a 30 mile per hour perpendicular impact into a fixed collision barrier. While the standard specifies a number of test conditions, it does not specify suspension height.

Looking at the Standard No. 204 as a whole, we believe it is clear that NHTSA explicitly decided to limit the standard's evaluation of steering control rearward displacement to how vehicles perform in 30 mph perpendicular impacts, even though the require ments have relevance at lower and higher speeds. Therefore, we agree that the standard's requirements need to be met only at suspension heights that occur at a 30 mph vehicle speed and with steered wheels positioned straight ahead.

With respect to Mazda's question concerning means of maintaining intended suspension height for compliance testing, please see our discussion provided with respect to Standard No. 111.

Standard No. 208, Occupant Crash Protection

In asking about Standard No. 208, you stated the following:

Section S8.1.1(d), "Vehicle test attitude," specifies the procedure for determining the vehicle test attitude that is to be used for testing. Specifically, this section requires that the vehicle's pretest attitude,

"...shall be equal to either the as delivered or fully loaded attitude or between the as delivered and fully loaded attitude." The as delivered attitude is defined by S8.1.1(d) as being, "...the distance between a level surface and a standard reference point on the test vehicle's body, directly above each wheel opening, when the vehicle is in its "as delivered" condition. The "as delivered" condition is the vehicle as received at the test site..." Because it is highly likely that the test vehicle wil l not have been operated for a period of days prior to arriving at the test site, the suspension height may have fallen by "y" mm. The fully loaded attitude is defined as the attitude of the vehicle when loaded in accordance with S8.1.1(a) or (b) and a determination of the height of the suspension at the fully loaded condition is made from the same level surface, using the same standard reference points, as were used to determine the "as delivered" condition. The definition of the "as delivered" condi tion is quite clear. However, Mazda interprets the "fully loaded condition" of the vehicle to be the condition when the vehicle's ignition is "on." In this instance it is likely that the height of the standard reference points on the vehicles body when in the "fully loaded condition" relative to the level surface will be greater than for the "as delivered" condition. Conversely, conventional vehicle suspension systems will likely have an "as delivered" height greater than the "full loaded" height. H owever, this fact is of no importance as S8.1.1(d) states that the pretest vehicle attitude may be, "...between the as delivered and the fully loaded attitude." With respect to the injury criteria specified by section S6 of this standard, Mazda's interp retation is that these criteria must be met with the vehicle's ignition in the "on" position only.

You then asked three questions, (1) whether Mazda's interpretation of the definition of the "fully loaded condition" is correct with respect to the condition of the ignition switch, (2) whether Mazda's interpretation of the irrelevance of the relative re lationship between the "as delivered" and "fully loaded" conditions is correct, and (3) whether Mazda's interpretation of the meaning of "between the as delivered and the fully loaded attitude" is correct.

In addressing your questions, I will begin by noting that Standard No. 208 specifies occupant protection requirements which must be met in specified crash tests at any impact speed up to and including 30 mph. While the standard specifies a number of tes t conditions, it does not specify suspension height. However, the standard does specify vehicle attitude, which is closely related to suspension height. In addressing how Standard No. 208 applies in the absence of a specification for vehicle height, th e relationship between the standard's attitude specification and vehicle height must be considered.

Section S8.1.1(d) specifies the attitude of the vehicle during testing, i.e., the angle of the vehicle relative to the ground. This test condition ensures that the vehicle is not overly tilted toward the front or back, or to one side. The section accom plishes this purpose by specifying that, during a compliance test, the height of the vehicle at each wheel is within a specified range. This range, which may be somewhat different for each wheel, is determined by looking at the vehicle in the "as delive red" condition and the "fully loaded" condition. A vehicle must meet the requirements of Standard No. 208 when its height at each wheel is

anywhere within the specified ranges.

On first glance, one might read section S8.1.1(d) to create a height requirement, since ranges of height are determined under that section (at each wheel). This would be incorrect, except in a very narrow sense, since Standard No. 208 does not specify, for vehicles with variable height suspension systems, what suspension height should be used in the two conditions ("as delivered" and "fully loaded") where the specified ranges of height are determined under section S8.1.1(d).

Looking at the Standard No. 208 as a whole, we believe it is clear that NHTSA explicitly decided to limit the standard's evaluation of occupant crash protection in frontal impacts to how vehicles perform in impacts of 30 mph or less, even though the requ irements also have relevance at higher speeds. It is our interpretation that the frontal crash test requirements need to be met at all suspension heights that can occur at speeds of 30 mph or less, with the vehicle operational. It is also our interpret ation that the crash test requirements need to be met only at suspension heights that can occur at the speed used in the crash test.

A remaining issue is how section S8.1.1(d) applies for vehicles with variable height suspension systems. As discussed below, vehicle attitude should be determined under this section using the actual suspension setting (or equivalent, if the setting is a utomatic) to be used in a crash test.

For purposes of illustration, I will assume a vehicle with two very different suspension height settings. It would not be appropriate to conclude that the ranges of height determined under section S8.1.1(d) should simultaneously cover both suspension he ights. Such ranges would be very large, and would not ensure that the vehicle is not overly tilted toward the front or back, or to one side. Moreover, such ranges would not be relevant to the real world, with respect to vehicle attitude.

Traditional vehicles can be viewed as having a single suspension "setting." This single suspension condition is used in determining vehicle attitude under section S5.8.8.1. The ranges of height result from the differences in loading under the "as deliv ered" and "fully loaded" conditions.

A single suspension "setting" (or equivalent, if the setting is automatic) should similarly be used in determining vehicle attitude for vehicles with variable height suspension systems. The "setting" should be the one to be used in a crash test.

With respect to Mazda's question concerning means of maintaining intended suspension height for compliance testing, please see our discussion provided with respect to Standard No. 111.

You also asked for an interpretation of section S8.2.7 of Standard No. 208. That section specifies additional conditions to be used for lateral moving barrier crash testing. Section S8.2.7(a) states that the vehicle is at rest in its "normal attitude." You stated that Mazda interprets the meaning of "normal attitude" to be that vehicle attitude which is intended

when the vehicle's ignition is in the "on" condition, with the vehicle loaded pursuant to S8.1.1(a) or (b), and while the vehicle is at rest. Standard No. 208 provides manufacturers the option of either equipping their vehicles with safety belts or meeti ng certain alternative requirements, including lateral moving barrier crash test requirements. These requirements are relevant at all vehicle heights that can occur during vehicle operation, regardless of speed. Moreover, NHTSA has not decided to limit the standard's evaluation of this aspect of safety performance to how vehicles perform at certain limited speeds. It is our interpretation that the lateral moving barrier crash test requirements, if applicable, must be met at all suspension heights that can occur with the vehicle operational. "Normal attitude" is the attitude determined under section S8.1.1(d). As discussed above, attitude for vehicles equipped with variable height suspension systems is determined under section S8.1.1(d) using the ac tual suspension setting (or equivalent, if the setting is automatic) to be used in a crash test.

Standards No. 212, Windshield Mounting; No. 219, Windshield Zone Intrusion; No. 301, Fuel System Integrity

In asking about Standards No. 212, No. 219, and No. 301, you noted that NHTSA has previously issued an interpretation to Mazda about how these standards apply to adjustable height suspension systems. In a letter dated August 10, 1982, the agency address ed a vehicle equipped with a suspension system having two height positions, one for normal highway driving and another for off-road driving, which could be selected by the driver. NHTSA stated the following:

(Safety Standards No. 212, No. 219, and No. 301) do not specify a height adjustment because almost all vehicles have a single, set adjustment. . . After careful consideration, it is the agency's position that such a vehicle capable of variable height adj ustment would have to comply with the vehicle adjusted to any position that is possible. This is true because the vehicle could be driven on the highway, for example, even if it were adjusted to the off-road position. Consequently, it is important that the vehicle comply with the standards in all positions.

You noted that while suspension height could be adjusted by the driver for the system discussed in the agency's previous interpretation, the active suspension system you are currently considering would use an on-board electronic controller to select susp ension height, and suspension height would not be adjustable by the driver. Consequently, according to your letter, only one unique set of suspension height parameters is possible for a given vehicle speed and loading condition as is the case with conve ntional suspension systems. You stated that because it is possible to determine exactly what the intended suspension height should be for a given situation, it is Mazda's opinion that the test vehicle should be tested at the intended suspension height g iven the specified speed and loading conditions. You also stated that, using an "intended purpose" argument, Mazda concludes that the requirements of the three standards are to be met only when the vehicle's ignition is "on." You then asked whether thes e suggested interpretations are correct.

Standard No. 212 specifies windshield retention requirements that must be

met in a specified frontal crash test at any impact speed up to and including 30 mph. Similarly, Standard No. 219 specifies windshield zone intrusion requirements that must be met in a specified frontal crash test at any impact speed up to and including 30 mph. Standard No. 301 specifies fuel system integrity requirements for several specified crash tests. These include a frontal crash test similar to those in Standards No. 212 and No. 219. Requirements for this test must be met at any impact speed up to and including 30 mph. Other tests include a rear moving barrier crash test, a lateral moving barrier crash test, and a static rollover test.

We agree that the requirements of Standards No. 212, No. 219, and No. 301 need not be met for vehicle heights that only occur when the engine is not on, since the requirements are only relevant in situations where the vehicle is operating. Looking at th e three standards as a whole, we believe it is clear that, for the frontal tests specified by the three standards, NHTSA decided to limit the standards' evaluation of safety performance to how vehicles perform in impacts of 30 mph or less, even though th e requirements have relevance at higher speeds. It is our interpretation that the frontal crash test requirements specified by these standards need to be met at all suspension heights that can occur at speeds of 30 mph or less, with the vehicle operatio nal. It is also our interpretation that the crash test requirements need to be met only at suspension heights that can occur at the speed used in the crash test.

We reach a different conclusion for Standard No. 301's other crash test requirements. These requirements are relevant at all vehicle speeds and suspension heights. Moreover, NHTSA has not decided to limit the standard's evaluation of these aspects of s afety performance to how vehicles perform at certain limited speeds. It is our interpretation that these crash test requirements must be met at all suspension heights that can occur with the vehicle operational.

Part 581 Bumper Standard

In asking about the Part 581 Bumper Standard, you noted that NHTSA has previously issued several interpretations of how the standard applies to vehicles with adjustable height suspension systems. In a letter to Subaru dated May 6, 1986, NHTSA stated the following:

Given the absence of a specific test condition concerning suspension height, it is our interpretation that a vehicle must be capable of meeting the standard's damage criteria at any height position to which the suspension can be adjusted. There is no la nguage in the test requirements of the standard limiting their applicability to "the manufacturer's nominal design highway adjusted height position."

This interpretation is consistent with the purpose of the Bumper Standard, set forth in section 581.2, to reduce physical damage to the front and rear ends of a passenger motor vehicle from low speed collisions. If a vehicle's suspension could be adjust ed so that its bumper height resulted in bumper mismatch with other vehicles in the event of low speed collisions, the reduction in physical damage attributable to the Bumper Standard would be defeated in whole or part.

In another letter, dated February 12, 1985, NHTSA stated that a vehicle is "required to meet the pendulum test of Part 581 in any vehicle use scenario in which the vehicle operates, and the barrier test of Part 581 when the engine is idling."

You suggested, for the barrier test, that the agency's May 1986 interpretation may be inappropriate for your active suspension system, since your system provides for only one suspension height when the engine is idling. You also suggested, for the pendu lum test, that these interpretations seem to be in conflict with the Bumper Standard's stated purpose to reduce physical damage to motor vehicles in low speed collisions. We assume that you are referring to the fact that your suspension system has heigh ts that occur only at speeds greater than 35 mph. You then requested that NHTSA provide an interpretation of Part 581 with respect to your system.

In addressing how Part 581 applies to vehicles equipped with an active suspension system, I will address separately the standard's barrier and pendulum tests. For the barrier test, a vehicle must meet specified damage criteria after an impact into a fix ed barrier that is perpendicular to the line of travel of the vehicle, at 2.5 mph. Section 581.6 sets forth conditions applicable to bumper testing. Under section 581.6(c), at the onset of a barrier impact, the vehicle's engine is operating at idling s peed.

Looking at the Bumper Standard as a whole, we believe it is clear that NHTSA decided to limit the barrier test's evaluation of bumper performance to how vehicles perform in 2.5 mph frontal impacts, even though the requirements have relevance at lower and higher speeds and when the vehicle is nonoperational. It is our interpretation that the barrier test requirements specified by this standard need to be met at all suspension heights that can occur at 2.5 mph.

We reach a different conclusion for the pendulum test, which serves the purpose of creating a bumper height requirement. This requirement is relevant at all vehicle speeds and suspension heights, and when the vehicle is nonoperational. I note that whil e Mazda is correct that the Bumper Standard's stated purpose is to reduce physical damage to motor vehicles in low speed collisions, NHTSA has justified the bumper height requirement on safety concerns related to "higher speed collisions." In proposing Standard No. 215, the predecessor of Part 581, the agency stated:

. . . in higher speed collisions the tendency of a bumper to override another or to ride under or over a guardrail creates hazards for vehicle occupants. Vehicles with interlocking bumpers block traffic and expose their occupants to considerable danger, particularly if they attempt to get out to unlock bumpers. By overriding or underriding a guardrail, a bumper may strike a supporting post, or similar fixed object, with serious consequences for the vehicle and its occupants. 35 FR 17999, November 24, 1970.

The relevance of the bumper height requirement to nonoperational

situations is also clear, e.g., to help protect parked cars.

Moreover, NHTSA has not decided to limit the bumper height requirement to how vehicles perform at certain limited speeds. It is our interpretation that the pendulum test requirements must be met at all suspension heights that can occur, regardless of ve hicle speed or whether the ignition is turned on.

This interpretation is consistent with an October 18, 1978 letter to Nissan, in which NHTSA addressed how the pendulum test applies to vehicles equipped with height control systems, including automatic height control systems. Among other things, the age ncy stated the following:

. . . There is no language in the pendulum test requirements of the standard which would limit their applicability to only the ignition-on or ignition-off situation or to the recommended driving position for normal roadways. The vehicle must be capable of meeting the pendulum test requirements at all stable bumper heights possible at unloaded vehicle weight.

Thus, in the situations described in Question 1 and 2 of your letter, in which an automatic height control system is employed, the vehicle must comply with the pendulum test requirements in both the ignition-on and ignition-off positions . . . .

I note that one of our past letters, a December 24, 1984 letter addressed to Porsche, appears to suggest that the pendulum test must be met in any setting in which the system operates "when the engine is idling." This might be read to suggest that the p endulum test need not be met when the vehicle is nonoperational. However, this interpretation cited section 581.6(c) in concluding that the engine is idling during Part 581 testing. Section 581.6(c) applies only to the barrier test and not the pendulum test. We therefore consider this interpretation to be incorrect to the extent that it is inconsistent with the analysis presented above.