ID: nht92-7.27

DATE: April 27, 1992

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA

TO: Michael Love -- Manager, Compliance, Porsche Cars North America, Inc.

TITLE: None

ATTACHMT: Attached to letter dated 4/3/92 from Michael Love to Paul J. Rice (OCC 7171)

TEXT:

This responds to your letter of April 3, 1992, requesting concurrence by this Office in your interpretation of the requirements of Standard No. 108 for the location of center highmounted stop lamps.

Porsche wishes to install a center lamp on the movable spoiler of its 911 Carrera, a configuration previously approved by this Office providing that all photometric and visibility requirements are met. However, S5.3.1.8 of Standard No. 108 requires that "If the lamp is mounted below the rear window, no portion of the lens shall be lower than 6 inches below the rear window on convertibles, or 3 inches on other passenger cars." Although Porsche's intended center lamp meets this requirement with the spoiler in the extended position (when the car reaches 45 to 55 mph and slows to 9 to 12 mph), at other times, when the spoiler is lowered, the center lamp would be 7.5 inches below the window on the coupe, and 9.5 inches for the convertible.

Nevertheless, you believe that this may be acceptable. You cite an opinion rendered Mazda in which NHTSA did not object to center lamps mounted on tailgates because, as we advised Mazda, the center lamp is a "supplementary" lamp, and that "Even if the deck, hatch, or tailgate upon which it is mounted should be open, following drivers may still observe the signals of the primary stop lamp lamps..." You further quote NHTSA's frequently repeated advisory that "Compliance of a vehicle is determined with respect to its normal driving position. . . ," and argue that Porsche's design "fulfills the spirit of the height requirements under all conditions" and the height requirement itself "under a majority of 'normal driving conditions.'" You further argue that even in the down position the triangular relationship between the center lamp and the stop lamps is retained. Finally, you argue that the proposed lamp conforms with NHTSA's philosophy to make Standard No. 108 more performance-oriented "by fulfilling the photometric requirements at all positions."

I am sorry that we cannot concur in your interpretation. When we judge whether a vehicle meets the location and visibility requirements of Standard No. 108, we determine compliance of the vehicle in what appears to us to be its normal operating or driving position. The fact that the vehicle may not comply under all conditions of operation is, of course, of concern to us, but we try to weigh the realities of vehicle design and usage against the need of the public for safety. In the Mazda interpretation, there was no question that the vehicle as manufactured would comply with the locational requirement for center lamps when the tailgate was closed. The "normal driving position" of a vehicle with a tailgate is with the tailgate in the closed position, and use of a vehicle with the tailgate not closed is likely to be infrequent compared with its use with the tailgate closed. In another interpretation, rendered years ago, the fact that a vehicle with hydraulic suspension would not

meet the minimum height requirements for headlamps with the vehicle at rest was considered a technical noncompliance only because by the time the vehicle was in its normal operating condition (with the engine running and the car ready to move into the stream of traffic), the suspension had raised the vehicle to a height where the headlamps exceeded the minimum height requirements.

By contrast, the center lamp on the Carerra will not meet the locational requirements from a state of rest up to a minimum of 45 mph, that is to say, under low-speed urban driving conditions where the center lamp is most likely to achieve its purpose of reducing the frequency and severity of rear end impacts. This, to us, is the "normal operating position" of the Carerra with respect to the location of the proposed center lamp.

I would like to close by pointing out that the agency went to a considerable extent in considering the comments of manufacturers before adopting the requirements of S5.3.1.8, in order to minimize design restrictions consistent with safety. NHTSA proposed three alternative locations, and adopted one that was less restrictive than any of the alternatives. Subsequently, pursuant to petitions for reconsideration by vehicle manufacturers, NHTSA relaxed the location requirements of S5.3.1.8 even further.

ID: NCC-240112-Goodyear Tire and Rubber Co.

August 8, 2024

Mark Cherveny
Manager, Global Relations, Standards & Compliance The Goodyear Tire & Rubber Company
200 Innovation Way
Akron, OH 44316-0001 

Dear Mr. Cherveny: 

This letter responds to Goodyear Tire & Rubber Company’s “Letter of Interpretation Request for § 571.139 S5.5(c): maximum inflation pressure,” which states that your company has received requests from original equipment vehicle manufacturers to stamp “350 kPa” on “Extra Load” passenger tires. Your request seeks clarification on whether your company is “permitted to stamp an Extra Load passenger tire with a maximum permissible inflation pressure of 350 kPa.” It then asks: “If this is permitted, then would the minimum breaking energy specified in [49 C.F.R.] § 571.109 Table I-C and the test inflation pressures specified in § 571.109 Table II – Test Inflation Pressures … still apply for strength testing?” 

In responding to this request, the National Highway Traffic Safety Administration (NHTSA) notes that the contents of this letter do not have the force and effect of law and are not meant to bind the public in any way. This letter is only intended to provide clarity regarding existing requirements under the law at the time of signature. 

As to your question whether “Extra Load” tires may be labeled as 350 kPa, NHTSA’s Federal Motor Vehicle Safety Standards (FMVSS) have no labeling requirements based on whether a passenger car tire is extra load or standard load. Thus, the FMVSS do not prohibit the proposed labeling on passenger car tires.1 

As to your question about the minimum breaking energy and inflation pressure tests in FMVSS No. 109, the testing requirements in Table I-C and Table II are based on a tire’s maximum inflation pressure and make no reference to whether the tire is labeled as standard load, extra

1 This letter, like your request, focuses solely on the FMVSS. Whether the proposed labeling complies with any other federal or state law or standards is outside the scope of this letter and we take no position on that question.

Page 2
Mr. Mark Cherveny 

load, or XL.2 Thus, passenger car tires with a maximum inflation pressure of 350 kPa are subject to the inflation pressures indicated for 350 kPa tires in the testing requirements set forth in Tables I-C and II. 

We note that your request did not inquire how the testing requirements in FMVSS 139, as opposed to those in FMVSS 109, apply to 350 kPa tires that have been stamped “Extra Load.” Because you did not request an interpretation of the testing standards in FMVSS 139, this letter does not provide such an interpretation. 

Finally, as you note in your letter, FMVSS No. 138—unlike FMVSS 109 and 139—does refer to the maximum inflation pressures for both standard load and extra load tires. The U.S. Tire Manufacturers Association has requested that NHTSA amend FMVSS No. 109 and 139 “to clarify marking and testing based on load classification,” and that it specifically clarify “whether 350 kPa is acceptable as a ‘Maximum Permissible Inflation Pressure’ marking for XL tires.”3 NHTSA is considering that request. However, as they currently stand, the testing requirements in Tables I-C and II of FMVSS 109 make no reference to load classification and are based solely on a tire’s maximum inflation pressure. 

I hope this information is helpful. If you have any further questions, please feel free to contact David Jasinski of my office at (202) 366-2992.

Sincerely,
ADAM RAVIV
Adam Raviv Chief Counsel

Dated: 8/8/24
Ref: Standard No. 109

2 FMVSS No. 109 has never referred to the terms “standard load,” “extra load,” or “reinforced” tires. 58 FR 59227 (Nov. 8, 1993).
3 See Docket No. NHTSA-2019-0011-0017.

ID: aiam4756

"Dear Mr. Gill: This responds to your request that this agenc determine that the new antitheft device proposed to be installed on the MY 1991 Honda Acura NS-X car line, represents a de minimis change in the system that was the basis for the agency's previous granting of a theft exemption for the car line beginning in MY 1991, and that therefore the Acura NS-X vehicles containing the new device would be fully covered by that exemption. As you are aware, the Acura NS-X car line was granted an exemption, pursuant to 49 CFR Part 543, from antitheft marking because Honda showed that the antitheft device to be used in lieu of marking on the car line was likely to be as effective as parts marking. This exemption was issued on February 5, 1990, and appeared in the Federal Register on February 9, 1990 (55 FR 4746). The agency granted the exemption from theft marking because the agency found that based on substantial evidence, the agency believed that the antitheft device is 'likely to be as effective in reducing and deterring motor vehicle theft as compliance with the parts-marking requirements of the theft prevention standard (49 CFR Part 541).' In the granting of the exemption from theft marking, the agency stated that it believed that the device will provide the types of performance listed in 49 CFR Part 543.6(a)(3): Promoting activation, attracting attention to unauthorized entries, preventing defeat or circumventing of the device by unauthorized persons, preventing operation of the vehicle by unauthorized entrants, and ensuring the reliability and durability of the device. In your letter, it was stated that beginning from MY 1991, Honda plans improvements in the antitheft device that is standard equipment on the Acura NS-X in two ways: First, the new antitheft system would be armed by using the auto door lock system control to lock either door. Honda states that in the system that was the subject of the exemption from the theft prevention system, it was necessary to use the control on the driver's door in order to arm the system. According to the attachment provided in your letter, this change would make it possible to arm the the theft deterrent system by locking either door even if the other door is left unlocked. Second, the radio would now be included in the alarm system. Thus, the alarm system will be activated if the radio terminal or the coupler is disconnected, or if the radio's wiring is cut. After reviewing the proposed changes to the componentry and performance of the antitheft device on which the exemption was based, the agency concludes that the changes are de minimis. While the new device has enhanced componentry and provides some aspects of performance not provided by the original device, it also continues to provide the same aspects of performance provided by the original device and relies on essentially the same componentry to provide that performance. Therefore, it is not necessary for Honda to submit a petition to modify the exemption pursuant to 49 CFR Part 543.9(c)(2). If Honda does not implement the new antitheft device as described in your letter, or delays implementation until after MY 1991, we request that Honda notify the agency of such decisions. It is my understanding that, in a May 16, 1990, telephone conversation between Brian Tinkler of Honda and Dorothy Nakama of NHTSA's Office of Chief Counsel, Mr. Tinkler confirmed that Honda was not requesting confidential treatment of any information provided in your letter. Therefore, a copy of your letter, and this response, will be placed together in NHTSA's public docket. Sincerely, Barry Felrice Associate Administrator for Rulemaking /";

ID: aiam2245

Dear Mr. Chauvin: This responds to your February 20, 1976, question whether this agenc considers Standard No. 222, *School Bus Passenger Seating and Crash Protection*, preemptive of New York State law or regulations mandating a 28-inch-high back and armrests for school bus passenger seating. Section 103(d) provides (15 U.S.C. S1392(d)):; >>>S 103<<< >>>(d) Whenever a Federal Motor vehicle safety standard under thi subchapter is in effect, no State or political subdivision of a State shall have any authority either to establish, or to continue in effect, with respect to any motor vehicle or item of motor vehicle equipment any safety standard applicable to the same aspect of performance of such vehicle or item of equipment which is not identical to the Federal standard. Nothing in this section shall be construed to prevent the Federal Government or the government of any State or political subdivision thereof from establishing a safety requirement applicable to motor vehicle equipment procured for its own use if such requirement imposes a higher standard of performance than that required to comply with the otherwise applicable Federal standard.<<<; Standard No. 222 specifies a formula for minimum seat back height tha necessitates a heights of at least 20 inches. It is the opinion of the NHTSA that any State requirement relating to seat back height, other than one identical to the Federal formula that establishes a minimum height of 20 inches, is preempted under S 103(d).; The second sentence of S 103(d) clarifies that the limitation on safet regulations of general applicability does not prevent governmental entities from specifying additional safety features in vehicles purchased for their own use. Thus, New York State or its political subdivisions could specify a seat back height higher than 20 inches in the case of public school buses. The second sentence does not, however, permit these governmental entities to specify safety features that prevent the vehicle or equipment from complying with applicable safety standards. A school bus manufacturer must continue to comply with all applicable standards.; There are presently no requirements in Standard No. 222 dealing wit armrests on school bus passenger seating. The question, therefore, becomes whether the Federal safety standards on school bus seating performance were intended generally to cover this aspect of performance, analogously to the situation in which Standard 108 was held to be preemptive in *Motorcycle Industry Council v. Younger*, No. CIV 574-126 (E. D. Cal. 1974). The guiding rule, as set forth by the U.S. Supreme Court in *Florida Lime & Avocado Growers v. Paul*, 373 U.S. 132, 141-142 (1963), is 'whether both regulations can be enforced without impairing federal superintendence of the field.' Under the accepted doctrines as set forth in cases such as *Thorpe v. Housing Authority of Durham*, 393 U.S. 268 (1969), the interpretation of this question by the administering agency is 'of controlling weight unless it is plainly erroneous or inconsistent with the regulation.'; The NHTSA has determined that the requirement for armrests by New Yor State does not conflict with or otherwise impair our present regulation of school bus passenger seating, and that armrests are not within the intended scope of the present Federal safety standards. Therefore, Standard No. 222 is not preemptive of the New York State regulation of armrests.; Yours truly, Frank Berndt, Acting Chief Counsel

ID: aiam4670

"Dear Mr. Rickert: Thank you for your letter seeking this agency' opinion as to whether the State of Maryland may amend its motor vehicle regulations to permit the installation of aftermarket tinting on motor vehicle windows, for individuals who may desire this for medical reasons. I am pleased to have this opportunity to describe the legal principles that relate to your question. The National Highway Traffic Safety Administration ('NHTSA') is responsible for issuing Federal motor vehicle safety standards that impose requirements for specific levels of safety performance for new motor vehicles and motor vehicle equipment. Federal Motor Vehicle Safety Standard No. 205, Glazing Materials (49 CFR 571.205), which has been in effect since 1968, imposes a minimum level of light transmittance of 70 percent in all areas requisite for driving visibility (which includes all windows on passenger cars). The purpose of this requirement is to ensure adequate visibility through the windows, thereby reducing the risk of a motor vehicle crash. Although Federal motor vehicle safety standards apply directly only to new vehicles and equipment, Federal law also imposes limits on the addition of tinting materials to motor vehicle glazing after vehicles have been purchased by consumers. Pursuant to section 108(a)(2) of the National Traffic and Motor Vehicle Safety Act, 15 U.S.C. 1397(a)(2), manufacturers, distributors, dealers, or motor vehicle repair businesses may not 'render inoperative' any equipment or element of design installed in compliance with a Federal safety standard. Thus, those businesses may not install tinting that reduces the light transmittance of windows covered by Standard 205 to a level below the Federal requirement of 70 percent, since that would make the windows 'inoperative' within the meaning of Standard 205. This Federal prohibition is similar to that imposed by section 22-104 of the Maryland Vehicle Law, which provides: A person may not willfully or intentionally remove or alter any safety device or equipment that has been placed on any motor vehicle . . . in compliance with any law, rule, regulation, or requirement of . . . the United States or of this State . . . unless the removal or alteration is permitted by rule or regulation adopted by the Maryland Motor Vehicle Administrator. The 'render inoperative' provision of Federal law does not apply to actions by individual vehicle owners. Therefore, each State may regulate the extent to which aftermarket tinting may be applied by vehicle owners to their own vehicles. Thus, although section 22-104 appears to preclude aftermarket tinting by any person if the result would be to reduce the level of light transmittance below 70 percent, Maryland may amend its rules or regulations to permit such tinting by individuals, for medical or any other reasons deemed valid by the State. However, Maryland has no authority to grant any exemptions, including medical exemptions, from the 'render inoperative' prohibition of Federal law that applies to commercial entities. Hence, regardless of any provisions of Maryland law, no manufacturer, distributor, dealer, or motor vehicle repair business may legally install window tinting film on a vehicle, unless the vehicle continues to comply with the Federal light transmittance requirements. In adopting Standard 205, NHTSA determined that a minimum light transmittance of 70 percent is necessary to meet the need for motor vehicle safety. This is the same level of light transmittance contained in the Safety Code of the American National Standards Institute. If, as your letter suggests, Maryland is considering permitting vehicle owners to modify their vehicles such that their windows will have a lower level of light transmittance, we would urge you to carefully consider the safety consequences of such an exemption. Please let me know if you need any further information on this subject. Sincerely, Paul Jackson Rice Chief Counsel";

ID: 8807

Ms. Gail Lindsey
Hillsborough County Public Schools
Risk Management and Safety Department
707 East Columbus Drive
Tampa, FL 33602

Dear Ms. Lindsey:

Your letter of June 23, 1993, to Mr. Ron Engle of the office of Transportation Safety Programs, this agency, was referred to this office for reply.

You explained in your letter and in a telephone conversation with Walter Myers of this office that it has been your School Board's policy to prohibit the use of mini-vans to transport school children to and from special events, requiring instead the use of school buses. You stated that the policy is controversial among parents, however, resulting in the School Board reconsidering the issue. You therefore requested information on "crash safety standards" of mini-vans or any other recommendations we can provide to assist the school board in making a safe and fair determination in the matter.

For your information, enclosed are copies of letters to Senator Jim Sasser dated July 7, 1992; Rep. John J. Duncan, Jr. dated May 29, 1992; Mrs. Alice Collins, dated August 1, 1988; a pamphlet issued by this agency entitled Federal Motor Vehicle Safety Standards and Regulations; a fact sheet issued by this office entitled Where to Obtain NHTSA's Safety Standards and Regulations; and a copy of Highway Safety Program Guideline No. 17, Pupil Transportation Safety, referred to in the letter to Mr. Duncan.

The enclosed materials should answer your concerns in this matter. I would like to emphasize that, as explained in the materials, it is NHTSA's position that a vehicle meeting Federal school bus regulations is the safest way to transport students. Despite the additional cost of these vehicles, I encourage Hillsborough County to give its most careful consideration to the possible consequences of transporting students in vehicles, such as mini-vans, that do not comply with school bus regulations.

Should you have any further questions or need any additional information, please feel free to contact Mr. Myers at this address or at (202) 366-2992.

Sincerely,

John Womack Acting Chief Counsel

Enclosures

ref:571 d:8/5/93

ID: nht88-3.94

TYPE: INTERPRETATION-NHTSA

DATE: 11/03/88 EST

FROM: ERIKA Z. JONES -- CHIEF COUNSEL NHTSA

TO: RICHARD W. WARD -- V. P; K-D LAMP COMPANY

TITLE: NONE

ATTACHMT: LETTER DATED SEPTEMBER 14, 1988 TO ERIKA Z. JONES, NHTSA ADMIN., FROM RICHARD W. WARD, V.P., K-D LAMP CO.; OCC 2555

TEXT: This is in reply to your letter of September 14, 1988, asking for a clarification of Federal requirements for the minimum lens area for turn signal lamps and stop lamps.

The understanding expressed in your letter is correct. The SAE materials for turn signal lamps and stop lamps for wide vehicles incorporated by reference in Table I apply to original equipment on vehicles currently being manufactured, and to equipment i ntended to replace such original equipment. These standards were expressly incorporated to supersede earlier versions of SAE standards for turn signal lamps and stop lamps. However, in recognition that original equipment lamps made to earlier SAE speci fications might not be compatible with the electrical systems of vehicles designed to conform to later SAE specifications, the agency adopted paragraphs S4.1.1.6 and 4.1.1.7, allowing the continued manufacture for replacement purposes only, of turn signa l lamps and stop lamps designed to conform to earlier specifications. Both sections incorporate in their text portions of the earlier SAE standards. Because the earlier specification for turn signal lamps, J588d, required an effective projected luminou s area not less than 12 square inches for turn signal lamps on wide vehicles, this requirement is also specified in S4.1.1.7 for replacement lamps manufactured in conformance with J588d.

In short, your interpretation is correct with respect to turn signal lamps manufactured for installation on vehicles whose overall width is 80 inches or more. Single compartment turn signal lamps designed to conform to SAE J588e need meet only a minimum luminous lens area of 8 square

inches. But if a turn signal lamp is manufactured to replace a turn signal lamp that was designed to conform to SAE J588d, its minimum luminous lens area is 12 square inches.

I hope this clarifies the matter for your customer.

ID: 1985-04.35

TYPE: INTERPRETATION-NHTSA

DATE: 11/25/85

FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA

TO: Mr. John L. O'Connell

TITLE: FMVSS INTERPRETATION

TEXT:

November 25, 1985 Mr. John L. O'Connell Public Transportation Administrator Department of Motor Vehicles State of Connecticut State Street Wethersfield, CT 06109-1896 Dear Mr. O'Connell: This is in reply to your letter of October 8, 1985, to Jeffrey Miller, former Chief Counsel of this agency. You have asked whether a new style school bus warning lamp system developed by the Whelen Engineering Company meets the requirements of Motor Vehicle Safety Standard No. 108 and referenced SAE standards, and whether such a system can be installed and used on school buses in compliance with Federal regulations. Pursuant to paragraph S4.1.4 of Standard No. 108, a school bus must be equipped with a system of red lamps, or red and amber lamps meeting SAE Standard J887 School Bus Red Signal Lamps, July 1964 (copy enclosed). The Whelen system is said to comply with SAE J887 May 1982, with the possible exception of dimensions. The requirements that the Whelen system must meet are those of the 1964 version of J887. Dimensional specifications are not included in the 1964 version, however, the minimum effective projected luminous lens area requirement of 19 square inches must be met. The test report indicates that the Whelen lamp meets the minimum photometrics of both the 1982 and 1964 versions of J887 and its dimensions, 7" x 2.75", indicate that the minimum luminous lens area requirement may also be met. However, the test report indicates that the light flashes at a rate of 55 cycles per minute. The Whelen lamp therefore does not comply with the 1964 requirement that school bus warning lamps flash at a rate of 60-120 cycles per minute (nor the 1982 SAE specifications of 1-2 H which is 60-120 cycles per minute). For this reason, the Whelen system does not meet Federal requirements and cannot be installed on school buses certified as meeting all applicable Federal motor vehicle safety standards. Sincerely, Original Signed By Erika Z. Jones Chief Counsel Enclosure

ID: 8088

Mr. Frank E. Timmons
Rubber Manufacturers Association
1400 K St., N.W.
Washington, DC 20005

Dear Mr. Timmons:

This responds to your letter about our November 1992 letter to the Under Secretary, Kuwait Ministry of Commerce. In that letter, NHTSA discussed Federal requirements for tires sold in the United States for passenger cars and other "motor vehicles." You wish to ensure that the Under Secretary understands that the term "motor vehicles" only refers to vehicles "manufactured primarily for use on highways."

We are glad to clarify the meaning of the term "motor vehicle." "Motor vehicle" is defined in 102(3) of the National Traffic and Motor Vehicle Safety Act as "any vehicle driven or drawn by mechanical power manufactured primarily for use on the public streets, roads, and highways, except any vehicle operated exclusively on a rail or rails." (Emphasis added.) Thus, a motor vehicle is a vehicle that the manufacturer expects will use public highways as part of its intended function.

This agency has issued many interpretations of what is and what is not a "motor vehicle." In general, vehicles that are equipped with tracks or are otherwise incapable of highway travel are not motor vehicles. Likewise, vehicles that are designed and sold solely for off-road use (e.g., airport runway vehicles and underground mining vehicles) are not motor vehicles even if operationally capable of highway travel. They would, however, be considered motor vehicles if the manufacturer knew that a substantial proportion of its customers actually would use them on the highway.

Vehicles that use the public highways on a necessary and recurring basis are considered motor vehicles. Furthermore, even if the majority of a vehicle's use will be off-road but it will spend a substantial amount of time on-road, this agency has interpreted that to be a motor vehicle.

We appreciate your interest in this matter and will provide the Under Secretary with a copy of this letter. Please contact us if we can be of further assistance.

Sincerely,

John Womack Acting Chief Counsel

cc: Under Secretary, Kuwait Ministry of Commerce ref:109#119#571#574 d:2/11/93

ID: 3133o

Mr. Richard W. Ward
Vice President
K-D Lamp Company
1910 Elm Street
Cincinnati, OH 45210

Dear Mr. Ward:

This is in reply to your letter of September 14, l988, asking for a clarification of Federal requirements for the minimum lens area for turn signal lamps and stop lamps.

The understanding expressed in your letter is correct. The SAE materials for turn signal lamps and stop lamps for wide vehicles incorporated by reference in Table I apply to original equipment on vehicles currently being manufactured, and to equipment intended to replace such original equipment. These standards were expressly incorporated to supersede earlier versions of SAE standards for turn signal lamps and stop lamps. However, in recognition that original equipment lamps made to earlier SAE specifications might not be compatible with the electrical systems of vehicles designed to conform to later SAE specifications, the agency adopted paragraphs S4.l.l.6 and 4.l.l.7, allowing the continued manufacture for replacement purposes only, of turn signal lamps and stop lamps designed to conform to earlier specifications. Both sections incorporate in their text portions of the earlier SAE standards. Because the earlier specification for turn signal lamps, J588d, required an effective projected luminous area not less than 12 square inches for turn signal lamps on wide vehicles, this requirement is also specified in S4.1.1.7 for replacement lamps manufactured in conformance with J588d.

In short, your interpretation is correct with respect to turn signal lamps manufactured for installation on vehicles whose overall width is 80 inches or more. Single compartment turn signal lamps designed to conform to SAE J588e need meet only a minimum luminous lens area of 8 square inches. But if a turn signal lamp is manufactured to replace a turn signal lamp that was designed to conform to SAE J588d, its minimum luminous lens area is 12 square inches.

I hope this clarifies the matter for your customer.

Sincerely,

Erika Z. Jones Chief Counsel

/ref: 108 d:ll/3/88