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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



Displaying 1771 - 1780 of 16506
Interpretations Date
 

ID: aiam0230

Open
David Sugarman, Esq., 119 West 57th Street, New York, New York 10019; David Sugarman
Esq.
119 West 57th Street
New York
New York 10019;

Dear Mr. Sugarman: In response to your letter of April 16 I enclose copies of Federa Motor Vehicle Safety Standards Nos. 107 (Reflecting Surfaces) and 108 (Lamps, Reflective Devices, and Associated Equipment). Copies of the ASTM and SAE standards cross-referenced in the Federal standards are available from the American Society for Testing and Materials and the Society of Automotive Engineers. You may find particularly helpful SAE Handbook Supplement 19, 'SAE Technical Reports Referenced in Federal Motor Vehicle Safety Standards'.; The answer to your first question is that Standard No. 108 require passenger cars manufactured on or after January 1, 1970, to be equipped with a total of 4 side marker lamps and 4 side marker reflectors, one marker and one reflector, amber in color, on each side of the vehicle 'as far forward as practicable', and one marker and one reflector, red in color, on each side of the vehicle, 'as far to the rear as practicable'. Between January 1, 1969 and January 1, 1970 the option of reflectors or markers, or a combination of the two was permitted. Prior to January 1, 1969 the Federal lighting standard did not apply to passenger cars. I will note in passing that the rear marker lamps on the Monteverdi displayed at the recent New York show were amber and must be changed to red before these vehicles are sold. There are no requirements as to size and shape of lamps and reflectors, but the SAE standard applicable to them and incorporated by reference in Standard No. 108 do set forth certain photometric requirements which must be met.; In answer to your second question, Table III of Standard No. 10 requires tail lamps to be red, but permits stop lamps and rear turn signals to be either red or amber. A proposal has been issued however (35 F.R. 106) that stop lamps be red only on passenger cars manufactured on or after January 1, 1971.; You have asked in your third question whether headlamps may be place in the grille. The answer to this is yes, provided that this location meets the lateral spacing and height above road surface requirements of Table IV of Standard No. 108. Also, headlamps must not be covered by a grille or plastic shield when in use.; Standard No. 107 does not specify a particular color for the horn rin and hub of the steering assembly but it does specify a maximum permissible value for specular glass.; Finally, other than Standard Nos. 205 (Glazing Materials) and 21 (windshield Mounting which all passenger cars must meet, there is no 'specific safety requirement as to the windshield' for convertibles, and there is no 'requirement as to a roll bar'.; Sincerely, Lawrence R. Schneider, Chief, Regulations Division

ID: aiam4273

Open
Mr. George Ziolo, 16182 Arena Drive, Ramona, CA 92065; Mr. George Ziolo
16182 Arena Drive
Ramona
CA 92065;

Dear Mr. Ziolo: Thank you for your letter of September 19, 1986, concerning th labeling requirements of Standard No. 209, *Seat Belt Assemblies*. Those requirements provide that each safety belt is to be labeled with the year of its manufacture. You asked whether the year of manufacturer can be shown in code. As explained below, the answer is no, the standard does not provide for showing the year of manufacture in code.; S4.1(j) of the standard requires each safety belt to be permanently an legibly labeled with the name of the manufacturer, distributor, or importer, the model of the safety belt model, and 'the year of manufacture.' The standard specifically requires the date of manufacture to be provided on the belt and does not provide for the use of a code to represent that date.; The purpose of the labeling requirement is to make it possible for th agency and consumers to identify easily the manufacturer of the safety belt for the purpose of noncompliance and safety-related defect investigations and notification and remedy campaigns. In addition, having the date of manufacture clearly marked on the belt assists consumers in determining whether a particular belt complies with the latest requirements of Standard No. 208 or some earlier version of those requirements. It also assistant the agency in compliance testing of aftermarket and other safety belts because it enables the agency to determine easily which version of the standard should be applied to that safety belt. Having the year shown in a code can complicate the easy identification of which safety belts are covered by an investigation or campaign and make it more difficult to determine which version of the standard applies to the safety belt.; If you have any further questions, please let me know. Sincerely, Erika Z. Jones, Chief Counsel

ID: aiam4789

Open
Mr. Robert Roden Roden & Hayes 2015 First Avenue No., Suite 400 Birmingham, AL 35203; Mr. Robert Roden Roden & Hayes 2015 First Avenue No.
Suite 400 Birmingham
AL 35203;

"Dear Mr. Roden: This responds to your questions about the requirement for key-locking systems in section S4.2(b) of Federal Motor Vehicle Safety Standard No. 114, Theft Protection (49 CFR 571.114). As explained below, the enclosed copy of the agency's recent final rule amending this provision may be relevant to your inquiry (55 FR 21868, May 30, 1990). By way of background, the National Traffic and Motor Vehicle Safety Act, ('Vehicle Safety Act,' 15 USC 1381 et seq.) requires every new motor vehicle sold in the United States to be certified as complying with all applicable Federal motor vehicle safety standards. The Vehicle Safety Act specifies that the manufacturer must certify that each of its vehicles complies with all applicable safety standards in effect on the date of manufacture. Any person violating the Vehicle Safety Act by manufacturing or selling new noncomplying vehicles may be liable for potential penalties of $1,000 per violation up to $800,000 for a related series of violations. One such Federal safety standard is Standard No. 114, Theft Protection, which applies to passenger cars, and to trucks and multipurpose passenger vehicles having a gross vehicle weight rating of 10,000 pounds or less. Your first question asked whether section S4.2(b) requires key locking systems to prevent removal of the ignition key except when the transmission is in the 'park' position. Section S4.2(b) currently requires such vehicles to have a 'key-locking system that, whenever the key is removed, will prevent...(b) either steering or forward self-mobility of the vehicle, or both.' However, the agency has recently amended section S4.2(b) to read as follows: Each vehicle shall have a key-locking system that, whenever the key is removed, prevents: (a) the normal activation of the vehicle's engine or motor, and (b) either steering or forward self-mobility of the vehicle or both. For a vehicle equipped with an automatic transmission with a 'park' position, the key-locking system shall prevent removal of the key unless the transmission or transmission shift lever is locked in 'park' or becomes locked in 'park' as the direct result of removing the key. You should be aware that this amendment takes effect on September 1, 1992. For vehicles manufactured before September 1, 1992, S4.2(b) merely requires that when the key is removed, the key-locking system must prevent steering or forward self-mobility, or both. This provision does not address the issue of the transmission's position at the time of key removal. In contrast, under the recent amendment applicable to vehicles manufactured on or after September 1, 1992, S4.2(b) requires automatic transmission vehicles to prevent removal of the key unless the transmission or transmission shift lever is locked in 'park' or becomes locked in 'park' as the direct result of removing the key. Your second question asked whether a replacement key-locking system is required to comply with Standard No. 114. Because Standard No. 114 applies to new motor vehicles and not to motor vehicle equipment, the standard does not in itself require aftermarket replacement systems to comply with its requirements. However, you should be aware that section 108(a)(2)(A) of the Vehicle Safety Act prohibits manufacturers, distributors, dealers, or motor vehicle repair businesses from knowingly 'rendering inoperative,' in whole or in part, any device or element of design installed on or in a vehicle to comply with an applicable safety standard. Your third question asked how long the key locking system is required to perform under S4.2(b) of the standard. The Vehicle Safety Act only requires manufacturers to assure that vehicles and equipment comply with applicable safety standards at the time of the first consumer purchase. However, please note that if at any time a manufacturer or the agency determines that a vehicle or item of equipment contains a safety-related defect, which could result from the failure of a system to operate properly, the manufacturer is required to notify all product purchasers of the defect and remedy the defect without charge. See 15 U.S.C. 1411-1414. I hope this information is helpful. If you have any further questions, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosures";

ID: aiam1071

Open
Mr. R. K. Ferwerda, President, Great Southern Equipment Company of Tampa, 1023 South 50th Street, Tampa, FL 33619; Mr. R. K. Ferwerda
President
Great Southern Equipment Company of Tampa
1023 South 50th Street
Tampa
FL 33619;

Dear Mr. Ferwerda: This is in reply to your letter of January 31, 1973, requesting 'a application form and requirements for the mounting of hydraulic cranes behind the cab of . . . trucks'.; Under NHTSA regulations, the operations you perform appear to make yo a final-stage manufacturer who is responsible for the conformity of the completed vehicle to the Federal Motor Vehicle Safety Standards, and for certifying conformity in accordance with NHTSA Certification regulations (49 CFR Part 567), and regulations regarding Vehicles Manufactured in Two or More Stages (49 CFR Part 568). As a manufacturer you are also required to submit certain information required by Part 566, 'Manufacturer Identification'.; Copies of NHTSA regulations may be obtained as indicated on th enclosed. 'Where to Obtain Motor Vehicle Safety Standards and Regulations'. We have no requirements involving application to this agency. If after reviewing the regulations you have specific questions, we will be happy to answer them.; Yours truly, Richard B. Dyson, Assistant Chief Counsel

ID: aiam4623

Open
Mr. Robert V. Potter, Jr. Spalding & Evenflo Companies, Inc. 5750-A North Hoover Blvd. P.O. Box 30101 Tampa, FL 33630; Mr. Robert V. Potter
Jr. Spalding & Evenflo Companies
Inc. 5750-A North Hoover Blvd. P.O. Box 30101 Tampa
FL 33630;

Dear Mr. Potter: This responds to your March 17, 1989, letter askin whether the National Highway Traffic Safety Administration (NHTSA) requires child restraint manufacturers to make spare parts available for their products for a specified amount of time. I regret the delay in responding. NHTSA has addressed the availability issue you raise in a July 31, 1986, letter to Ms. Ziomek of Washington, Michigan, a copy of which is enclosed. As explained in that letter, NHTSA does not specifically require child restraint manufacturers to make replacement parts available for any child restraint. However, manufacturers must be prepared to meet their recall obligations under the National Traffic and Motor Vehicle Safety Act. That law requires that, in the event of a safety-related defect or non-compliance with a safety standard, manufacturers provide a remedy without charge to consumers for eight years after purchase. With regard to your statement about an existing Federal regulation requiring automobile manufacturers to make replacement parts available for 10 years, NHTSA does not have such a requirement. However, automobile manufacturers have the same recall responsibilities described above for safety-related defects and non-compliances. Further, we understand manufacturers commonly follow a voluntary practice of making replacement parts available for vehicle parts likely to become worn or damaged for a 10-year period, which to the best of our knowledge has usually proven adequate to meet general consumer demand. I hope this information is helpful. Sincerely, Stephen P. Wood Acting Chief Counsel Enclosure;

ID: aiam1421

Open
Gorou Utsunomiya,Branch Manager,Toyo Kogyo Co., Ltd.,U.S.A. Representative Office,Detroit Branch,23777 Greenfield Rd. S462,Southfield, Michigan 48075; Gorou Utsunomiya
Branch Manager
Toyo Kogyo Co.
Ltd.
U.S.A. Representative Office
Detroit Branch
23777 Greenfield Rd. S462
Southfield
Michigan 48075;

Dear Mr Utsunomiya:#This responds to your February 1, 1974, request fo interpretation of Standard No. 106, *Brake hoses*, concerning 'collapse' in S9.2.8, an incorrect value in Table VI, and proper labeling format.#Your confusion about the meaning of 'collapse' in S9.2.8 points out that the requirement was inadvertently changed between notices 7 and 8 and that it should require 'no leakage or separation of the inner tube from the fabric reinforcement of the hose'. The language will be amended in the near future.#In our response to petitions for reconsideration of Standard 106, we corrected the 5/64 value (question 2) and we accommodated labeling of short hose by permitting labeling separated by any amount up to 6 inches (question 4). You must use one line for labeling required by Standard 106, but you may interrupt the stripe on the opposite side of the required labeling with labeling for other countries, in accordance with S5.2.1 (question 5). in answer to question 3, the fractions should read 3/16, as your indicate you wish to do it.#Your associate, Mr Hirai, asked our office for an explanation of the certification requirements of S144 of the National Traffic and Motor Vehicle Safety Act of 1966, as they apply to items of motor vehicle equipment to which a standard applies. I have enclosed a notice of clarification. #Yours truly,Richard B. Dyson,Assistant Chief Counsel;

ID: aiam1134

Open
Mr. Doran Rhodes, Assistant to the President, Highway Aircraft Corporation, 909 Fifth Avenue, Box 651, Sidney, NE 69162; Mr. Doran Rhodes
Assistant to the President
Highway Aircraft Corporation
909 Fifth Avenue
Box 651
Sidney
NE 69162;

Dear Mr. Rhodes: This is in reply to your letter of April 24, 1973, to Mr. Schneide asking for an interpretation that the Fascination vehicle your company proposes to manufacture is 'an automobile.' You state that you 'are currently testing both a single wheel and a dual wheel arrangement in the front, and it is not clear yet which one will prevail.'; If the final configuration of the Fascination were that of four-wheeled vehicle it would be categorized as a 'passenger car' under the Federal Motor Vehicle Safety Standards. Currently all three-wheeled vehicles are classified under our regulations as 'motorcycles.' Under a recent rule making proposal, a copy of which I enclose, the definition of a motorcycle with three wheels would be restricted to those lacking a full or partial enclosure for the driver, clearly excluding the Fascination. If the proposal is adopted, and you choose the three-wheel configuration for the Fascination, then the vehicle would probably be classified as a passenger car. It is possible that some adjustments would be made in the standards applied to three-wheeled or other lightweight vehicles, on petitions received from those interested.; Yours truly, Richard B. Dyson, Assistant Chief Counsel

ID: aiam3109

Open
Mr. C. J. Newman, Vice President, Engineering, The Grote Manufacturing Company, State Rt. 7 - P.O. Box 766, Madison, IN 47250; Mr. C. J. Newman
Vice President
Engineering
The Grote Manufacturing Company
State Rt. 7 - P.O. Box 766
Madison
IN 47250;

Dear Mr. Newman: This is in reply to your letter of August 23, 1979, to the former Chie Counsel Joseph J. Levin, Jr. You have asked whether a double-faced turn signal front side marker lamp 'meets the intent' of Motor Vehicle Safety Standard No. 108, and you enclosed a sample of the lamp for our inspection.; You have quoted paragraph 3.4 of SAE Standard J588e, September 1970 which states 'the flashing signal from a double faced signal lamp shall not be obliterated when subjected to external light rays from either in front or behind at any and all angles.' It is not possible to make a definitive statement about your lamp without actually subjecting it to a representative external light source such as the headlamps of a vehicle in proximity to the vehicle to which the lamp is mounted, but its design appears adequate to meet the intent of paragraph 3.4. Any changes in design of the lenses or baffling from that of the sample lamp submitted, however, might transmit more light from external sources and may not meet paragraph 3.4.; We would also like to observe that since the side marker signal use the front and rear lenses of the turn signal in a single compartment a high intensity ratio of turn signal to side marker signal will be needed if the steady burning light from the side marker lamp is not to obscure the darker portion of the turn signal lamp.; Sincerely, Frank Berndt, Chief Counsel

ID: aiam4336

Open

Dear Mr.: Thank your for your letter requesting an interpretation of how Standar No. 205, *Glazing Materials*, would apply to your proposed 'head-up display.' You described your head-up display as a system consisting of components located in the instrument panel and windshield that are capable of optically projecting instrument readings so that they appear forward of the lower part of the windshield. You stated that having the readings projected in this manner places them closer to the driver's line of sight and thus allows the driver to view the information more readily and clearly than if the driver had to look for the information on the instrument panel. As discussed below, the agency has conclude that the standard does not prohibit the use of your proposed display.; Before discussing the substantive question you asked, I want to addres your request that the agency not publicly release two types of information contained in your letter. First, you requested the agency to provide confidential treatment to the detailed description of the technology used in your head-up display. Second, you requested that the agency not disclose the name of your company. You explained in your letter requesting confidential treatment that while the device has been installed on a car displayed at a public automobile show, the technical details of the device are not a matter of public knowledge. You subsequently provided the agency with a copy of your letter in which the proprietary technical details have been deleted. Because the technical details of your proprietary device have not been publicly disclosed, we will treat the technical details as confidential. In addition, we will not disclose the name of your company. However, since all for the agency's interpretations are a matter of pubic record, we will place a copy of your letter, which has been purged of the confidential information and your company name, and our response in the agency's public interpretation file.; In the copy of your letter that has been purged of confidentia information, you explain that your head-up display uses a small membrane that is attached to the windshield to reflect certain information from the instrument panel. You explained that the area of the windshield on which the membrane is attached can meet all of the applicable requirements of Standard No. 205 set for glazing materials used in a windshield, except the requirement that the light transmittance through the glazing material be at least 70 percent. You further explained that the membrane is not opaque, but does have a light transmittance that is less than 70 percent.; Based on your analysis of the requirements of Standard No. 205 and th requirements of the American National Standard 'Safety Code for Safety Glazing Materials for Glazing Motor Vehicles Operating on Land Highways,' (ANS Z26) incorporated by reference in Standard No. 205, you stated that the 70 percent transmittance requirement does not apply to all window areas. You noted that ANS Z26, a manufacturer can place a shade band on the upper edge of a windshield that has a light transmittance of less than 70 percent. You further noted that Standard No. 205 and ANS Z26 do not define the boundaries of the shadeband or set a minimum light transmittance level for the glazing materials used in the shadeband. Futhermore, you pointed out that Standard No. 205 and ANS Z26 do not specifically define what areas of the glazing are requisite for driving visibility.; In support of your position that the area of the windshield affected b your head-up display is not requisite for driving visibility, you noted that the membrane used in the display system covers a small area of the glazing that is located toward the lower left edge of the windshield. To demonstrate that the membrane is not within an area requisite for driving visibility, you examined the effect of the membrane's location on the ability of the car to comply with the requirements of Standard No. 103, *Windshield Defrosting and Defogging*, and 104, *Windshield Wiping and Washing*. Standards No. 103 and 104 define three different areas on the windshield and require the wiping system and the defrosting/defogging system of a car to wipe or defrost/defog a prescribed minimum percentage of each of the three areas. Based on your evaluation of a windshield that has a head-up display membrane, you demonstrated that the area of the windshield covered by the membrane represent only a minimal portion of the three areas of the windshield that are required by those standards to be wiped or defrosted/defogged. You further demonstrated that a car could comply with the requirements of Standard Nos. 1-3 and 104 even though the membrane slightly projects into the areas regulated by those standards.; In further support of your position that the head-up display is no located in an area requisite for driving visibility, you provided a comparison of the effects of the head- up display versus the effects of a vehicle's hood design or unretracted head lamp on a driver's forward and downward visibility. In this comparison, you presented information that measure, from the driver's eyepoint, the locations and amount of the driver's forward visibility that would be obstructed by portions of the hood design and by an unretracted head lamp. You then compared the obstruction caused by those design features with the effects of the head-up display on the driver's visibility. The information you provided shows that a vehicle's hood design or an unretracted head lamp can extend as far up in the driver's field of view as the head-up display and provide more obstruction to a driver's forward visibility than the head- up display.; You are correct that while Standard No. 205 and ANS Z26 apply a 7 percent light transmittance requirement to areas of the glazing that are 'requisite for driving visibility,' neither Standard No. 205 nor ANS Z26 specifically defines what areas of the glazing are requisite for driving visibility. In fact, as you pointed out in your letter ANS Z26 specifically defines what areas of the glazing are requisite for driving visibility. In fact, as you pointed out in your letter, ANS Z26 specifically provides, in a footnote to S4.2 of ANS Z26, an exception to the 70 percent light transmittance requirement. The footnote explains that a manufacturer can provide an area on the glazing, such as a shade band, that has a light transmittance of less than 70 percent as long as the areas requisite for driving visibility have a light transmittance of 70 percent. In interpreting the requisite for driving visibility requirement, the agency has not specified a minimum area of the windshield that is requisite for driving visibility. Instead, the agency has said, such as in a letter of February 15, 1974, to Mr. George Nield, that in determining what areas are requisite for driving visibility, the agency will use an approach of determining those areas by reference to vertical heights in relation to the driver's eyes.; (I believe it is important to note that the agency's decision, in th context of shade bands, not to adopt proposed specific size limits on areas of the windshield which could have less than 70 percent transmittance, was based on the conclusion that such a requirement was not necessary because of the voluntary practices of the industry. Thus, although the agency has not adopted a specific requirement, it has been relying on the good faith adherence of the industry to that voluntary practice on shade bands. The agency first proposed a limit on the size and light transmittance of shade bands in a notice published in November 1978(43 FR 51677). In commenting on the notice, several vehicle manufacturers said that such a requirement was not needed since the industry was voluntarily following a Society of Automotive Engineers Recommended Practice (SAE J100, 'Passenger Car Glazing Shade Bands') that established boundaries for shade bands used on glazed surfaces in passenger cars. As NHTSA explained in a notice published in January 1981 (46 FR 40), the agency decided to defer further action on the proposed shade band limit until it gathered additional data on the adequacy of the voluntary industry practice.); After reviewing the information you have submitted, the agency ha concluded that the membrane used in your system is located in an area of the glazing that is not requisite for driving visibility. The agency reached this conclusion based on the specific fact of your particular design and the following considerations. The membrane used in your system is small in size, is located near the bottom edge of the glazing area and toward the corner of the glazing area, and although the membrane has a light transmittance that is less than 70 percent, it is not opaque.; In determining that your head-up display is not located in an are requisite for driving visibility, the agency also considered the effect of the display on a car's ability to meet the requirements of Standard Nos. 103 and 104. Although Standard Nos. 103 and 104 do not define the limits of what areas are requisite for driving visibility, the areas of the windshield covered by the performance requirement of those standards do indicate the agency's concern that, at a minimum, specified portions of those areas of the windshield be clear during inclement weather inclement weather to provide the driver with a view of the road. The information provided with your letter shows that a small portion of the head-up display in your vehicle partially falls within the defined areas, but the vehicle still meets the performance requirements of the standards.; Another factor in the agency's decision was the information in you letter showing a comparison of the effects of the membrane versus the effects of a vehicle's hood design or unretracted head lamp on a driver's forward visibility. The information you provided shows that a vehicle's hood design or an unretracted head lamp can intrude as far up into the driver's field of view as the head-up display and provide more obstruction to a driver's forward visibility than head-up display. This information is an additional indication that the head-up display is not located within an area that is requisite for driving visibility.; Although the agency has concluded that in your particular case you head-up display is not in an area requisite for driving visibility, the agency believes that with the advent of new glazing and other technologies using the windshield, such as the head-up display, it is appropriate to again re-examine the issue for whether to specify the size of the area of the windshield that are requisite for driving visibility. It is apparent that there will be a number of new technologies using the windshield. For example, the March 30, 1987 issue of *Automotive News* carried a news article announcing the development, by PPG Industries and Flight Dynamics, of a 6 inch square holographic display on the windshield.; NHTSA believes that the issues associated with these devices should b addressed in a comprehensive manner. In particular, the agency believes that it needs further information on such issues as whether the areas on the windshield used by these display devices need to have a lower light transmittance value and, if so, what that value should be, where on the windshield the devices can be located, and what limitations should be placed on their size. Addressing these issues in a comprehensive manner by setting general performance requirements applicable to all such devices, regardless of the technology used, will avoid the inconsistencies and possible design specific limitations that might arise if the agency attempts to provide case-by-case interpretations for each specific design. For all these reasons, NHTSA has concluded that it will address these issues through a comprehensive rulemaking action.; You raised one final issue in your letter. You asked that if the agenc concluded that your head-up display does not comply with Standard No. 205, it should regard the noncompliance as a technical one which does not warrant enforcement. Since the agency has concluded that your head-up display does not violate the requirements of Standard No. 205, it should regard the noncompliance as a technical one which does not warrant enforcement. Since the agency has concluded that your head-up display does not violate the requirements of Standard No. 205, the issue is moot.; If you have any further questions, please let me know. Sincerely, Erika Z. Jones, Chief Counsel

ID: aiam1564

Open
Mr. P.K. Kamath, Oshkosh Truck Corporation, P.O. Box 2566, Oshkosh, WI 54901; Mr. P.K. Kamath
Oshkosh Truck Corporation
P.O. Box 2566
Oshkosh
WI 54901;

Dear Mr. Kamath: This responds to your July 2, 1974, question whether a truck complie with the dynamometer requirements of S5.4 of Standard No. 121, *Air brake systems*, if its brakes are actuated by smaller slack adjusters and brake chambers than those specified by the brake manufacturer to establish torque levels which comply with the standard. Your question arises under the interim requirements of S5.3.1.2 and the full requirements of S5.4.2 and S5.4.3 as they apply to the on/off-highway category.; Standard No. 121 is a vehicle requirement, and the NHTSA will conduc compliance testing for dynamometer requirements using the force levels applied to the brakes on the particular vehicle it is testing. This means that if you use 5.5-inch slack adjusters and 30-inch brake chambers on your truck, the NHTSA would use the force applied by these components in its compliance testing. There is no prohibition to your modifying the brake manufacturer's 'recommended package' to suit your needs. However, you should be able to show that, in the exercise of due care, the brake assembly meets the requirements of S5.4 as modified.; If you believe that the established dynamometer requirements conflic with optimum handling and stopping performance, you may, under NHTSA procedural rules (49 CFR 563, copy enclosed) petition to modify the standard.; In response to your July 10, 1974, letter asking whether a air-over-hydraulic front brake is subject to certain requirements of Standard No. 105a, I enclose a preamble to that standard which states that air-over-hydraulic systems are regulated only by Standard No. 121.; Yours truly, Richard B. Dyson, Acting Chief Counsel

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.