NHTSA Interpretation File Search
Overview
NHTSA's Chief Counsel interprets the statutes that the agency administers and the standards and regulations that it issues. Members of the public may submit requests for interpretation, and the Chief Counsel will respond with a letter of interpretation. These interpretation letters look at the particular facts presented in the question and explain the agency’s opinion on how the law applies given those facts. These letters of interpretation are guidance documents. They do not have the force and effect of law and are not meant to bind the public in any way. They are intended only to provide information to the public regarding existing requirements under the law or agency policies.
Understanding NHTSA’s Online Interpretation Files
NHTSA makes its letters of interpretation available to the public on this webpage.
An interpretation letter represents the opinion of the Chief Counsel based on the facts of individual cases at the time the letter was written. While these letters may be helpful in determining how the agency might answer a question that another person has if that question is similar to a previously considered question, do not assume that a prior interpretation will necessarily apply to your situation.
- Your facts may be sufficiently different from those presented in prior interpretations, such that the agency's answer to you might be different from the answer in the prior interpretation letter;
- Your situation may be completely new to the agency and not addressed in an existing interpretation letter;
- The agency's safety standards or regulations may have changed since the prior interpretation letter was written so that the agency's prior interpretation no longer applies; or
- Some combination of the above, or other, factors.
Searching NHTSA’s Online Interpretation Files
Before beginning a search, it’s important to understand how this online search works. Below we provide some examples of searches you can run. In some cases, the search results may include words similar to what you searched because it utilizes a fuzzy search algorithm.
Single word search
Example: car
Result: Any document containing that word.
Multiple word search
Example: car seat requirements
Result: Any document containing any of these words.
Connector word search
Example: car AND seat AND requirements
Result: Any document containing all of these words.
Note: Search operators such as AND or OR must be in all capital letters.
Phrase in double quotes
Example: "headlamp function"
Result: Any document with that phrase.
Conjunctive search
Example: functionally AND minima
Result: Any document with both of those words.
Wildcard
Example: headl*
Result: Any document with a word beginning with those letters (e.g., headlamp, headlight, headlamps).
Example: no*compl*
Result: Any document beginning with the letters “no” followed by the letters “compl” (e.g., noncompliance, non-complying).
Not
Example: headlamp NOT crash
Result: Any document containing the word “headlamp” and not the word “crash.”
Complex searches
You can combine search operators to write more targeted searches.
Note: The database does not currently support phrase searches with wildcards (e.g., “make* inoperative”).
Example: Headl* AND (supplement* OR auxiliary OR impair*)
Result: Any document containing words that are variants of “headlamp” (headlamp, headlights, etc.) and also containing a variant of “supplement” (supplement, supplemental, etc.) or “impair” (impair, impairment, etc.) or the word “auxiliary.”
Search Tool
NHTSA's Interpretation Files Search
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ID: aiam0221OpenJohn S. Cushman, Esq.,Special Assistant Attorney General, Consumer Division, 102 State Capitol, St. Paul, Minnesota 55101; John S. Cushman Esq. Special Assistant Attorney General Consumer Division 102 State Capitol St. Paul Minnesota 55101; Dear Mr. Cushman: Your letter of February 16, 1979, transmitting Mr. John M. Schneider' letter, concerning tire selection for his 25,500-lb. GVW Truck, to the Federal Trade Commission has been referred to the National Highway Safety Bureau for reply.; There are no Federal standards at the present time for Tire Selectio and Rims for trucks. We are currently in the rule making phase to establish such a standard, however, we anticipate the effective date of this standard to be more than a year in the future.; The lack of Federal Standards in no way relieves a vehicle manufacture from his responsibility to design vehicles with equipment that will perform safely. this was evidenced in recent negotiations between General Motors and the National Highway Safety Bureau on a problem concerning three piece Kelsey-Hayes wheels. As you may know, at present, there are no standard covering wheel performance.; Sincerely, Rodolfo A. Diaz, Acting Associate Director, Motor Vehicl Programs; |
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ID: aiam5473OpenMr. Ed Irvine Midwest Conservation Systems P.O. Box 397 Silver Lake, KS 66539; Mr. Ed Irvine Midwest Conservation Systems P.O. Box 397 Silver Lake KS 66539; Dear Mr. Irvine: This responds to your letter asking whether a newl manufactured commercial utility trailer must be equipped with an emergency breakaway system. You state that your customer wishes to purchase a trailer without the battery powered breakaway system that comes with the trailer. Instead, you would like to install your solar energized breakaway system. In a December 7, 1994 telephone conversation with Mr. Marvin Shaw of my staff, you stated that the trailers in question are typically small utility trailers that do not rely on the use of air pressure. I am pleased to have this opportunity to explain the applicable requirements issued by this agency, the National Highway Traffic Safety Administration (NHTSA). You may also wish to request an interpretation of 49 CFR 393.43 from the Federal Highway Administration (FHWA), which is the agency that issued that regulation. By way of background information, NHTSA and FHWA are both part of the United States Department of Transportation. Each agency has the authority to issue regulations related to your question. NHTSA, which regulates newly manufactured vehicles, has the authority to issue Federal motor vehicle safety standards (FMVSS) which apply to new motor vehicles and new items of motor vehicle equipment. FHWA, which regulates the use of commercial motor vehicles, has the authority to issue Federal Motor Carrier Safety Regulations (FMCSRs), which are applicable to commercial motor vehicles and their operators. We have referred your letter to the Federal Highway Administration's (FHWA) Office of Motor Carrier Standards, since that agency issued 49 CFR 393.43. While NHTSA has the authority to issue FMVSSs, the agency has not issued any FMVSS that would directly affect the braking performance of a small utility trailer, unless the trailer relies on air pressure. Therefore, if the trailers in question are not air braked vehicles, then you would not need to certify that such a trailer's braking performance complies with an FMVSS, since no applicable FMVSS exists. Please note that your solar energized trailer breakaway system would be considered 'motor vehicle equipment' within the meaning of the statute administered by NHTSA. If this system contained a defect (either in manufacture, design, or performance) that relates to motor vehicle safety, the manufacturer would be required to conduct a recall campaign to notify owners and to remedy the defect free of charge. I hope this information is helpful. If you have any questions about NHTSA's safety standards, please feel free to contact Marvin Shaw at this address or by telephone at (202) 366-2992. If you wish to contact someone in the FHWA's Office of Chief Counsel concerning the motor carrier standards, please call Charles Medalen at (202) 366-1354. Sincerely, Philip R. Recht Chief Counsel; |
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ID: aiam1963OpenMr. Gary W. Walters, 152 Westwood Drive, Clarion, Pennsylvania 16214; Mr. Gary W. Walters 152 Westwood Drive Clarion Pennsylvania 16214; Dear Mr. Walters: This is in response to your letter requesting information concernin standards that relate to the construction of a pick-up camper.; Although your letter is unclear on this point, we assume that you questions relate to the building of a single slide-in camper for your own use. If this is the case, the only standards with which you must comply are Standard No. 126, *Truck-camper loading*, and Standard No. 205, *Glazing materials*. In addition, your camper should be certified in accordance with 49 CFR Part 567.; The NHTSA can provide no information concerning methods of constructio of these or other items of motor vehicle equipment.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5189OpenMr. Ray Kesler Kesler Research Enterprises 5508 Cahuenga Blvd. North Hollywood, CA 91601; Mr. Ray Kesler Kesler Research Enterprises 5508 Cahuenga Blvd. North Hollywood CA 91601; "Dear Mr. Kesler: This responds to your follow-up letter to the agenc in which you request further interpretation of the requirements in Standard No. 111 relating to convex mirrors. Specifically, you asked about how section S5.4.1, which limits the radii of curvature's permissible variance, relates to S12, which specifies the procedures for determining a convex mirror's average radius of curvature. I am pleased to have this opportunity to respond to your request. As Marvin Shaw of my staff informed your associate Lawrence Hufstedler in a telephone conversation, section S12 sets forth a detailed multi-step procedure for calculating a convex mirror's average radius of curvature. The first step is to take ten readings on the mirror surface with a 3-point linear spherometer as specified in Figure 1 of the Standard. (See S12.1.) The second step is to convert each of the ten readings to a 'radius of curvature calculation' using Table 1. (See S12.5.) The third step is to calculate the 'average radius of curvature' by adding all 10 radius of curvature calculations and dividing by 10. (See S12.6.) Mr. Hufstedler asked how S5.4.1 affects the calculations. That section states 'none of the radii of curvature readings shall deviate from the average radius of curvature by more than 12.5 percent.' This means that some of the radii of curvature readings may be up to 12.5 percent different than the average radius of curvature. In numerical terms, this means that if a mirror had an average radius of curvature of 36 inches a given radii of curvature reading could be as low as 31.5 inches and as high as 40.5. I hope this information is helpful. Please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992 if you have any further questions or need additional information. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0671OpenMr. George C. Nield, Engineering Advisor, Messrs. Busby Rivkin Sherman Levy and Rehm, 816 Connecticut Avenue, N.W., Washington, DC 20006; Mr. George C. Nield Engineering Advisor Messrs. Busby Rivkin Sherman Levy and Rehm 816 Connecticut Avenue N.W. Washington DC 20006; Dear Mr. Nield: In your letter of April 5, you ask whether certain items of lightin equipment that you listed must be certified as conforming to applicable Federal standards, even though the assemblies of which they are a part may require certification.; This will confirm your understanding that the listed items need not b certified. The items of lighting equipment requiring certification are those equipment items specified in Tables I and III of Standard No. 108.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4632OpenMr. Mike Sazio S.C. Manufacturing, Inc. 11879 Woodbury Avenue Garden Grove, CA 92643; Mr. Mike Sazio S.C. Manufacturing Inc. 11879 Woodbury Avenue Garden Grove CA 92643; "Dear Mr. Sazio: This responds to your letter concerning th application of our regulations and Federal motor vehicle safety standards to your company's manufacture of 'convertible vinyl tops for Jeeps and similar vehicles.' I regret the delay in responding. You asked which Federal safety standards apply to these convertible tops that you sell in both the new vehicle market and the aftermarket. You were especially interested in standards for 'windows and door handles.' There are two Federal safety standards (copies enclosed) that would apply to your product: (1) Standard No. 205, Glazing Materials, and (2) Standard No. 302, Flammability of Interior Materials. While the brevity of the description of your product makes it difficult for us to determine whether our standard for door handles (Standard No. 206, Door Locks and Door Retention Components) applies, we believe that the standard does not apply to your product because the tops, which apparently incorporate doors, are readily removable. By way of background information, the National Highway Traffic Safety Administration (NHTSA) has the authority under the National Traffic and Motor Vehicle Safety Act (copy enclosed) to establish Federal motor vehicle safety standards for new motor vehicles and items of motor vehicle equipment. NHTSA, however, does not approve motor vehicles or motor vehicle equipment. 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. This process requires each manufacturer to determine in the exercise of due care that its products meet all applicable Federal requirements. The agency periodically tests vehicles and equipment for compliance with the standards, and also investigates other alleged safety-related defects. If you or the agency determines that a noncompliance or safety-related defect exists, you are obligated to notify purchasers of your product and remedy the problem without charge. Manufacturers who fail to provide notification of or remedy for a defect or noncompliance may be subject to a civil penalty of up to $1,000 per violation. (A general information sheet describing manufacturers' responsibilities under the Safety Act is enclosed.) The Safety Act defines the term 'motor vehicle equipment' as follows: 'Motor vehicle equipment' means any system, part, or component of a motor vehicle as originally manufactured or any similar part or component manufactured or sold for replacement or improvement of such system, part, or component or as any accessory or addition to the motor vehicle ...' (/102(4)) This definition includes the product your company manufactures since the convertible tops are components manufactured and sold either as a replacement or improvement of the convertible top or as an addition to vehicles that have no existing top. Since your product is considered an item of motor vehicle equipment, S.C. Manufacturing Inc., as the manufacturer of the equipment, must ensure that the convertible tops comply with all applicable Federal motor vehicle safety standards and contain no safety-related defects. If your product contains glazing material, Standard No. 205 (49 CFR /571.205, Glazing Materials) directly applies to that glazing material. Standard No. 205 is an equipment standard which sets performance requirements for glazing materials used in new motor vehicles and glazing materials sold as items of motor vehicle equipment, including glazing used in convertible tops. Any glazing in the convertible tops that your company manufactures for new or used vehicles must therefore conform to the applicable specifications set forth in Standard No. 205. The standard establishes both performance requirements, including those regulating the light transmittance and abrasion resistance of glazing, and labeling requirements applicable to the glazing used in your product. If your convertible top is added to a new vehicle, i.e., before the vehicle is sold for the first time to a consumer, then it must comply with Standard No. 302, Flammability of Interior Materials (49 CFR /571.302). Standard No. 302 applies to certain vehicle occupant compartment components, including convertible tops, on new completed motor vehicles. Persons selling new vehicles equipped with your convertible top must ensure that the vehicles, including your top, conforms to Standard No. 302. Generally speaking, while the requirements of Standard No. 302 apply to convertible tops incorporated in new vehicles, they do not apply to convertible tops added to used vehicles, i.e., vehicles which have been sold for the first time to a consumer. Under this general rule, you are permitted to sell aftermarket convertible tops that do not comply with Standard No. 302 to vehicle owners who will add them to their used vehicles even if the addition of the top by the vehicle owners caused the vehicles to no longer comply with Standard No. 302. This general rule is, however, limited by the application of the provisions of /108(a)(2)(A) of the Vehicle Safety Act. That section specifies: 'No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative ... any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard ...' This section requires manufacturers, distributors, dealers or motor vehicle repair businesses (i.e., any person holding him or herself out to the public as in the business of repairing motor vehicles or motor vehicle equipment for compensation) installing your top on new or used vehicles to ensure that the addition of the apparatus would not negatively affect the compliance of any component or design on a vehicle with applicable Federal safety standards. For example, the commercial entity must ensure that the addition of the top does not degrade from the safety provided by flammable-resistant materials in the vehicle's interior compartment which have been installed in accordance with Standard No. 302. Installation of rapidly burning materials could vitiate the compliance of the materials which were present in the vehicle at the time of its sale to the first consumer and were certified as meeting FMVSS No. 302. Section 109 of the Act specifies a civil penalty of up to $1,000 for each violation of section 108. You should note that section 108(a)(2)(A) is not limited to Standard No. 302, but applies also to any modification of Federally-required safety systems or devices on new or used vehicles. Section 108(a)(2)(A) prohibits rendering inoperative the compliance of devices or elements of design with any applicable Federal safety standard. Thus, a commercial entity would be permitted to install your product only if the modification would not destroy or degrade from a vehicle's compliance with any applicable Federal requirements, such as those for lamps and reflective devices (Standard No. 108). Standard No. 206 applies to new vehicles, but not to new aftermarket motor vehicle equipment. Therefore, the doors on aftermarket Jeep top covers would not have to meet the standard. Further, doors on new Jeep vehicles would not have to meet the standard if they are 'designed to be easily attached to or removed from' the vehicle, as provided in paragraph S4 of Standard No. 206. To summarize the above discussion, any glazing in the convertible tops you manufacture must meet applicable requirements of Standard No. 205 regardless of whether the tops are sold in the aftermarket or to new vehicle purchasers. The effect of Standard No. 302 on your product depends on the circumstances surrounding installation of the product in new and used motor vehicles. If the convertible top does not meet Standard No. 302, the top cannot be installed in vehicles by any commercial business listed in /108(a)(2)(A) of the Safety Act. However, these convertible tops may legally be installed in vehicles by the owners of the vehicles. Your company would still have the responsibility under the Vehicle Safety Act to recall and remedy its products which are determined to contain a defect relating to motor vehicle safety, even if the convertible tops were installed by vehicle owners themselves. I hope this information is helpful. In addition to the materials described above, I have also enclosed an information sheet describing generally your responsibilities under the Vehicle Safety Act. Please contact my office if we can be of further assistance. Sincerely, Stephen P. Wood Acting Chief Counsel Enclosures"; |
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ID: aiam1430OpenMessrs. Nebe and Gartner, Continental Gummi-Werke, Aktiengeselischaft, Postfach 169, 3 Hannover, Germany; Messrs. Nebe and Gartner Continental Gummi-Werke Aktiengeselischaft Postfach 169 3 Hannover Germany; Gentlemen: This is in reply to your letter of January 29, 1974, raising certai questions about the effective date (September 1, 1974) of the Uniform Tire Quality Grading regulation. You pose two hypothetical questions, asking whether tires must be quality graded when they are to be placed on vehicles manufactured or imported after September 1, 1974. In the first situation, the tires are manufactured in July 1974, while the vehicle is manufactured in August 1974 and imported in October 1974. In the second, the tires are manufactured in August 1974, the vehicle is manufactured in September 1974 and imported in November 1974.; The Quality Grading regulation applies to tires rather than vehicles Its effective date of September 1, 1974, means that all passenger-car tires manufactured on or after that date must be graded in accordance with the regulation. There is no requirement, however, that vehicle manufacturers must use tires manufactured after that date. In each hypothetical question you present, the tires are manufactured before September 1, 1974, and therefore are not required to be graded. The date of manufacture or importation of the vehicle is immaterial.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4262OpenMr. Pete Cameron-Nott, 90 Horace Street, Startford, CT 06497; Mr. Pete Cameron-Nott 90 Horace Street Startford CT 06497; Dear Mr. Cameron-Nott: This is in reply to your letter of December 7, 1986, with respect t kit cars. Your first question concerns a 1965 Jaguar that has been rebodied but carries its original mechanical components, title, and identification number. The National Traffic and Motor Vehicle Safety Act does not require conformance with the Federal motor vehicle safety standards applicable to passenger cars if the passenger car to be imported into the United States was manufactured before January 1, 1968. However, certain of these standards cover vehicle components, and if the relevant components have been manufactured on or after January 1, 1968, these components would be subject to the applicable Federal safety standard. These components include brake hoses, lighting equipment, tires, retreaded tire, glazing materials (most importantly, the windshield must be marked AS-1), seat belt assemblies, and wheel coves (which may not incorporate winged projections). Although the 1965 Jaguar would have a new body, by retaining its original mechanical components, title, and identification number, it would be considered a 1965 model and not subject to the Federal motor vehicle safety standards applicable to passenger cars. But if any of the equipment listed above has been manufactured after January 1, 1968, those items must comply in order to be imported into this country.; You have asked how the situation would differ were the bodied Jaguar 1972 model, the other facts being identical. We would consider this car a 1972 model, and required to conform to all Federal motor vehicle safety standards that applied on the date of its original manufacture. Conformity could be achieved either before or after its importation into this country.; Your second question concerns 'a kit car consisting of both new an used components i.e. new body/chassis and used mechanicals from various sources including Ford/Triumph and M.G.' You have reported EPA's position that the year of the engine determines what standards are to be met, and you have asked if these are also DOT's requirements. The age of the engine is not the determining factor with us. Generally, the agency considers a kit car consisting of new body and new chassis to be a new motor vehicle, and required to meet all Federal motor vehicle safety standards applicable to new passenger cars as of the date of its assembly, even if some of its mechanical components have been used previously. This means that such components must not prevent the assembled vehicle from meeting those standards.; If you have further questions we would be pleased to answer them. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam4798OpenMr. S. Kadoya Manager Safety and Technology Mazda Research and Development of North America, Inc. 1203 Woodbridge Avenue Ann Arbor, MI 48105; Mr. S. Kadoya Manager Safety and Technology Mazda Research and Development of North America Inc. 1203 Woodbridge Avenue Ann Arbor MI 48105; Dear Mr. Kadoya: This responds to your request for interpretations o 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. NOTE: THIS IS PART II OF AN INTERPRETATION LETTER TOO LONG TO BE ACCEPTED INTO THE DATABASE AS IS. PART I COVERS COMPLIANCE ISSUES (PART 571), AND STANDARDS 108, 211 AND 204. ITS KEY NUMBER IS 5023. 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 test 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 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 S8.1.1(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' 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 S8.1.1(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 interpretation 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 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 you 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 S8.1.1(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 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 an 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 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 S8.1.1(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 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 S8.1.1(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 S5.8.8.1. 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. 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 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 S8.1.1(d). As discussed above, attitude for vehicles equipped with variable height suspension systems is determined under section S8.1.1.(d) using the actual 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 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. 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 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. 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 is situations where the vehicle is operating. Looking at the three standards as a whole, were 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 thought 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. 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 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 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 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 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 adjusted so that its bumper height resulted in bumper mismatch with other vehicles in the event of low speed collision, 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 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 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 fixed 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 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, event 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 collision, 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 occupant 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 requirements 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 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 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 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 pendulum 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. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam1060OpenMr. R. E. Jones, Product Engineer, The Flxible Co., Loudonville, OH 44842; Mr. R. E. Jones Product Engineer The Flxible Co. Loudonville OH 44842; Dear Mr. Jones: This is in reply to your letter of February 21, 1973, requesting tha you be permitted to affix the Certification label for buses manufactured by your company on the right side of the dash panel, as illustrated in a picture (your serial; B72-4375-2) you have enclosed. As pictured, the label in the location you have chosen is easil readable without moving any part of the vehicle except an outer door, as required by section 567.4(c) of the Certification regulations, and your request that you be permitted to affix the label for these vehicles in that location is hereby approved.; Sincerely, Francis Armstrong, Director, Office of Standard Enforcement, Motor Vehicle Programs; |
Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.