ID: aiam5475

"Dear Mr. Bonvin: This is in reply to your letter of December 15, 1994 with respect to the relationship of certain DOT regulations to the Cheyenne, a small front-wheel drive utility vehicle that you wish to import and distribute in the United States. You have asked the following questions: 'What are the procedure to follow in order to be categorize Small Volume manufacturer?' Your question assumes that we have a category of 'small volume manufacturer.' We do not, and there is no exclusion from the Federal motor vehicle safety standards (FMVSS) based upon the volume produced by the manufacturer. All motor vehicles must comply with all FMVSS, unless the agency has exempted them from one or more of the standards. We do recognize limited production volume in the regulation under which a manufacturer who produces less than 10,000 motor vehicles of all types may apply for a temporary exemption on the basis that compliance would cause it substantial economic hardship, and must provide production information as part of its application. 'Is there really a big difference on the test in order to certified between small volume and over 10000 vehicles?' As indicated above, if a manufacturer produces less than 10,000 vehicles, that fact is relevant only if that manufacturer wishes to file a hardship exemption application. If a small volume manufacturer has not been exempted, it must comply with the same requirements as apply to those whose yearly production exceeds 10,000. 'Is there any difference between two seaters or four seaters on crash test?' That is a question to be answered by a vehicle manufacturer. If a four-seater is heavier than a two-seater, the difference in weight could make a difference in whether a vehicle with a borderline design passes or fails a crash test. 'Is there a rear crash impact?' Yes. FMVSS No. 301 Fuel System Integrity specifies a 30 m.p.h. moving barrier rear impact test. 'Do we need Air Bags if we have Seat belts?' Currently, vehicles like the Cheyenne are not required to have air bags. However, as explained below, air bags are one means of complying with a the automatic protection requirement which is being phased in for vehicles like the Cheyenne, and eventually the Cheyenne will be required to have air bags for both the driver and right front passenger. Generally, Jeep-type vehicles are considered to be 'multipurpose passenger vehicles' (MPVs). Based on your description, we also assume that the Cheyenne will have a GVWR of 8,500 pounds or less. A requirement in FMVSS No. 208, Occupant Crash Protection, which is being phased in requires a specified percentage (varying by year) of each manufacturer's light trucks (a category which includes MPVs with a GVWR of 8,500 pounds or less) manufactured on or after September 1, 1994 to be equipped with automatic crash protection. The two types of automatic crash protection currently offered are automatic safety belts and air bags. A recent amendment of FMVSS No. 208 will require at least 80 percent of each manufacturer's light trucks manufactured on or after September 1, 1997 and before September 1, 1998 to be equipped with an air bag and a manual lap/shoulder belt at the driver's and right front passenger's seating positions. All light trucks manufactured on or after September 1, 1998 must be equipped with an air bag and a manual lap/shoulder belt at these seating positions. 'Do we need a buzzer for the seat belt?' Yes, an audible warning indicator is required. 'Is the dashboard need to be padded?' We cannot answer your question. That decision is to be made by the manufacturer if its tests show that the dashboard is within the head impact area and that some type of padding is necessary to meet FMVSS No. 201 Occupant Protection in Interior Impact. The FMVSS are performance standards and we do not impose design restrictions on the manufacturer, such as requiring that the dashboard be padded. 'Is there any specific ways on how to install the windshield?' No, because that would be design restrictive and, as noted above, the FMVSS are performance standards. The performance requirement for windshields is in FMVSS No. 212 Windshield Retention which specifies what the windshield mounting must do in a 30 mph frontal barrier crash. However, if the MPV is an open vehicle with a fold-down windshield, FMVSS No. 212 does not apply to it. 'What is the surface of the windshield that need to wiped? As far as Windshield Wipers, how many cycles and how many different speed?' You will find the answers to your questions in FMVSS No. 104 Windshield Wiping and Washing Systems. For a copy of these and all our regulations, you should have a copy of 'Title 49 Code of Federal Regulations Parts 400-999'. This is available from the U.S. Government Bookstore at ARCO Plaza, C-Level, 505 South Flower Street, Los Angeles. Sincerely, Philip R. Recht Chief Counsel";

ID: NCC-231121-001 Autoliv (Veoneer) Spotlight Interpretation 1

June 27, 2024

Richard Seoane 

VP Operations and Business Development 

Thermal Product Area 

Veoneer 

420 South Fairview Avenue Goleta, CA 93117 

Dear Mr. Seoane: 

This responds to your request dated October 10, 2016, concerning the application of Federal Motor Vehicle Safety Standard (“FMVSS”) No. 108, Lamps, reflective devices, and associated equipment, to a lighting system you describe in your letter. As I explain below, based on your description of the system we agree that it is supplemental lighting, but disagree with your assertion that it would not impair the effectiveness of any of the required lighting equipment. 

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. 

Description of the Marking Light and the Request for Interpretation 

In your letter, you request an interpretation of FMVSS No. 108 as applied to an auxiliary light designed to prevent nighttime crashes (the Marking Light). As you describe it, the Marking Light consists of two auxiliary spotlights operated independently of the headlighting system. The spotlights are mounted symmetrically about the vertical centerline of the vehicle, below the headlamps, and pointed down at a fixed angle. The Marking Light operates independently of the upper and lower beam headlamps to produce a narrow, white-light beam pointed down to highlight the path to an object (such as a pedestrian) in or near the forward roadway so that the driver can see it. The Marking Light is activated and controlled by Autoliv’s Night Vision System, which has an infrared camera that detects pedestrian, bicyclist, and animal hazards up to 100 meters in front of the vehicle. The Night Vision System alerts the driver with in-vehicle 

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Richard Seoane 

visual (e.g., head-up display icon and/or dash icon) and audible signals indicating activation of the Marking Light and directs the Marking Light to illuminate the path over the ground to the hazard to visually alert the driver of the presence and location of the hazard. The system does not engage vehicle steering or brakes. The Marking Light cannot be activated manually by the driver or continuously operated; it is activated only by the night vision system when a hazard is detected to assist the driver in seeing the hazard but does not assist the driver in seeing the roadway. You state that the Marking Light is disabled in the presence of oncoming and preceding traffic so that it does not glare drivers on a wet or shiny roadway. 

You explain your position that the Marking Light is a supplemental lamp, not a required lamp such as a headlamp. You then make a variety of different arguments (and provide data) to support your view that the Marking Light does not impair the effectiveness of any of the required lighting. We summarize these arguments in more detail where relevant in the discussion below. 

Applicable Requirements 

FMVSS No. 108, which is codified at 49 C.F.R. § 571.108, sets requirements for vehicle lighting. The standard requires a variety of types of lighting, depending on vehicle type and size, and specifies requirements for these required lighting elements. The standard also sets requirements (referred to as “if equipped” requirements) for some non-mandatory lighting devices, such as daytime running lamps. 

Lighting devices that FMVSS No. 108 does not require or regulate as “if equipped” lighting devices are considered supplemental (or auxiliary) lighting devices. Supplemental lighting is generally permitted as long as it does not impair the effectiveness of any of the lighting equipment required by the standard. See FMVSS No. 108 S6.2.1 (also referred to as the “impairment” provision). 

FMVSS No. 108 applies only to original equipment and lighting equipment manufactured to replace original lighting equipment required by FMVSS No. 108. The standard does not directly apply to supplemental lighting devices sold in the aftermarket. Instead, supplemental lighting offered as an aftermarket accessory is subject to the “make inoperative” prohibition (49 U.S.C. § 301222), which prohibits certain specified commercial entities (such as dealers or repair shops) from taking a vehicle out of compliance with an FMVSS. In applying the “make inoperative” prohibition to aftermarket accessory lighting, NHTSA typically asks whether the accessory lighting would impair the effectiveness of any required lighting. Generally, if an item of accessory lighting would not be permitted as original equipment, commercial entities will not be permitted to install the lighting as an aftermarket accessory for a vehicle in use. 

While the vehicle manufacturer has the legal responsibility under the National Traffic and Motor Vehicle Safety Act (Safety Act) to certify that the vehicle complies with FMVSS No. 108 and all other applicable FMVSS, as a practical matter, vehicle manufacturers generally insist that equipment manufacturers provide assurance that their products meet federal standards. The judgment of impairment is one made, in the first instance, by the person installing the device. That decision, however, may be questioned by NHTSA if it appears clearly erroneous. 

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Richard Seoane 

Discussion 

The threshold issue presented by your request is whether the Marking Light is part of the required headlighting system and thus subject to the requirements applicable to headlighting systems, or supplemental lighting that is regulated by FMVSS No. 108’s impairment provision. We agree with you that the Marking Light would be considered supplemental lighting. 

FMVSS No. 108 requires vehicles to be equipped with one of several permissible headlighting systems.1 Headlighting systems are comprised of headlamps and associated hardware. The purpose of headlamps is primarily to provide forward illumination.2 In determining whether lighting equipment that provides forward illumination is part of the required headlighting system or supplemental lighting, NHTSA looks at several factors. These factors have included, among other things: (1) where the lamp directs its light; (2) whether it uses a headlamp replaceable light source to emit a beam that provides significantly more light flux than supplemental cornering lamps or fog lamps; (3) whether the lamp is intended to be used regularly, or is limited to more narrow driving conditions and situations; or (4) whether there is a manual on/off switch.3 

None of our previous interpretations appear to have addressed a frontal lighting concept precisely like the Marking Light. We agree with you, based on the information you have provided us, that it is supplemental lighting because it is not intended to be used regularly, but is instead a narrow beam that is activated only when there is a hazard forward of the vehicle such as a pedestrian or animal near the roadway. 

Because the Marking Light would be considered supplemental lighting, it is permitted as long as it does not impair the effectiveness of any lighting equipment required by the standard. In its previous interpretation letters, NHTSA has identified a number of different ways that a supplemental lamp could impair the effectiveness of the required lighting.4 

With respect to the Marking Light, there are two types of impairment that are potentially relevant. One is the potential to confuse other drivers arising from the Marking Light’s color, location, or activation pattern.5 The other potentially relevant type of impairment is the potential for glare to other road users due to the intensity of the Marking Light. We address each of these potential types of impairment below. 

1 FMVSS No. 108 Table I-a; S10.
2 FMVSS No. 108 S4 (“Headlamp means a lighting device providing an upper and/or a lower beam used for providing illumination forward of the vehicle.”).
3 See Letter from Jacqueline Glassman, Chief Counsel, to [Redacted] (Jan. 21, 2004). Prior to the 2004 interpretation letter, NHTSA issued several interpretations concerning auxiliary driving beams in which the agency treated those lamps as supplemental lighting without expressly considering the issue. See, e.g., Letter from Erika Z. Jones, Chief Counsel, to P. Soardo, Instituto Elettrotecnico Nazionale (May 22, 1987). If the lamps in question in those earlier interpretations would be considered supplemental lighting under the factors set forth in the 2004 interpretation, they may be consistent with that later interpretation. There is not, however, sufficient information about the lighting systems at issue in those earlier interpretation letters to allow application of the factors from the 2004 interpretation. In any case, the 2004 interpretation has been, to date, NHTSA’s view of the issue.
4 See, e.g., Letter from Jonathan Morrison, Chief Counsel, to Paul Schaye, Pedestrian Safety Solutions (Sept. 9, 2019).
5 See id. 

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Richard Seoane 

Color and Location 

The impairment provision prohibits auxiliary lamp colors that are likely to confuse other road users.6 For auxiliary lamps located on the front of the vehicle, colors that could cause confusion include red (which could be confused with a tail lamp), green (which could be confused with a traffic signal), and blue (which could be confused with a law enforcement vehicle).7 

You state that because the Marking Light is white, it cannot be confused with a turn signal and would not conflict with the emergency (hazard) lamps or parking lamps. 

We agree that because the Marking Light is white and mounted below the headlamps, it would not likely be confused with the front turn signal (which is amber8) and would not conflict with the vehicle hazard warning (which consists of all required turn signal lamps flashing simultaneously9) or the parking lamps (which must be white or amber10). I therefore agree that the color and location of the Marking Light would not cause confusion with the vehicle’s signal lamps. 

Activation Pattern 

FMVSS No. 108 requires that all auxiliary lamps be steady burning except for auxiliary lamps that supplement required lamps that flash, such as turn signals.11 This requirement means that the lamp must be steady burning when activated, not that it is prohibited from being activated or deactivated automatically.12 However, the (de)activation of the lamp cannot be so frequent or random that the lamp would distract or confuse other road users. For example, a lamp that activates and deactivates on an extremely short time interval due to sensitivity to slight changes in conditions would not be considered steady-burning.13 NHTSA has also interpreted the steady- 

6 Id.
7 Id.
8 FMVSS No. 108 Table I-a.
9 Id. S6.6.2; S4 (definition of vehicle hazard warning signal flasher).
10 Id. Table I-a.
11 See, e.g., Letter from Jonathan Morrison, Chief Counsel, to Paul Schaye, Pedestrian Safety Solutions (Sept. 9, 2019); Letter from Anthony Cooke, Chief Counsel, to Kerry Legg, New Flyer, Inc. (Feb. 21, 2008). Before 2007, FMVSS No. 108 included an explicit requirement that, with certain exceptions (e.g., turn signal lamps), all lamps on a vehicle, including auxiliary lamps, must be steady burning. In 2007, NHTSA implemented an administrative rewrite of FMVSS No. 108 which, among other things, converted the blanket “steady burning” requirement (and its exceptions) into individual activation requirements for each type of required lamp. See 72 FR 68234 (Dec. 4, 2007). Although the reorganized rule no longer includes a blanket “steady burning” requirement, NHTSA stated in the preamble to the reorganized rule that its “rewrite of FMVSS No. 108 is considered administrative in nature because the standard’s existing requirements and obligations are not being increased, decreased, or substantively modified.” Id. Moreover, NHTSA continues to believe that flashing auxiliary lamps would impair the effectiveness of required lamps by distracting or confusing other road users.
12 See Letter from Jonathan Morrison, Chief Counsel, to Paul Schaye, Pedestrian Safety Solutions (Sept. 9, 2019).
13 See id. 

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Richard Seoane 

burning requirement to mean that headlamp intensity may modulate, but only if the changes in intensity are not detectable by the human eye.14 

You state that the Marking Light is steady burning in that it does not flash (cycle on and off). You state that the Marking Light is activated when the night vision system identifies a pedestrian, bicyclist, or large animal in or near the forward roadway as a hazard. When the object is no longer deemed a hazard, the night vision system switches off the Marking Light. We also understand that the intensity of the Marking Light does not modulate. 

We agree that, based on the facts represented to us in your letter, the Marking Light is steady burning and would therefore not violate the impairment provision in this respect. This conclusion assumes that the Marking Light does not activate and deactivate frequently (which could confuse or distract other road users) or change intensity while activated in a way that is detectable to the human eye. 

Brightness (Photometric Intensity) 

Supplemental lighting can also impair the effectiveness of the required lighting if it is so intense that it glares other road users15 or, relatedly, masks any of the required signal lighting.16 As a point of reference, we note that FMVSS No. 108 specifies two upper beam (or high beam) maxima, at H-V and 4D-V.17 The magnitude of the specified maxima depends on the type of upper beam system; for the purposes of this letter, we will compare the Marking Light to the highest specified maxima at each test point, which are 75,000 candela (cd) at H-V and 12,000 cd 

14 See, e.g., Letter from Stephen Wood, Acting Chief Counsel, to Kiminori Hyodo, Koito Manufacturing Co., Ltd. (Nov. 5, 2005); Letter from John Womack, Acting Chief Counsel, NHTSA, to Joe De Sousa (Mar. 10, 1994) (stating, in the context of a modulating motorcycle headlamp, that “there is no failure to conform if the modulating light from the lamp is perceived to be a steady beam”).
15 See, e.g., Letter from John Womack, Acting Chief Counsel, to Yoshiaki Matsui, Stanley Elec. Co., Ltd. (Sept. 20, 1995) (fog lamp supplementing lower beam) (“Finally, as a cautionary note, we believe that Stanley should evaluate the glare potential of the headlamp when the fog lamp and lower beam are operating simultaneously, as it is important to safety that oncoming drivers not be distracted or discomforted in the operation of their vehicles.”). Cf. Letter from Jacqueline Glassman, Chief Counsel, to Rusty Riggin, Willow Development (Aug. 2, 2002) (explaining that a supplemental rear cornering lamp could violate the impairment provision if it was so intense that it “create[d] distracting glare”).
16 See, e.g., Letter from Jonathan Morrison, Chief Counsel, to Paul Schaye, Pedestrian Safety Solutions (Sept. 9, 2019) (“NHTSA has in the past stated that auxiliary lamps that were so bright as to ‘mask’ adjacent required turning signal lamps would be prohibited due to impairment.”); Letter From Samuel Dubbin, Chief Counsel, to Richard Russell (Dec. 22, 1995) (“[W]e would regard the vehicle manufacturer’s certification as negated if the brightness and location of the auxiliary lamps were such as to affect an oncoming driver’s ability to perceive the front turn signals.”).
17 FMVSS 108 Table XVIII. The photometry requirements specified in Table XVIII consist of test points at which the intensity of the light is measured. The requirements at each test point consist of minima and/or maxima. The test points are defined with respect to an angular coordinate system relative to the headlamp. Thus, H-V identifies a test point zero degrees up and zero degrees down relative to the headlamp, and 4D-V identifies a test point 4 degrees down relative to the headlamp. See also Letter from Erika Jones, Chief Counsel, to Byung Soh, Target Marketing Systems (Sept. 13, 1988) (“Effectiveness may be impaired if the device creates a noncompliance in the existing lighting equipment or modifies its candlepower to either below the minima or above the maxima permitted by the standard.”); Letter from Erika Jones, Chief Counsel, to George Ziolo (Sept. 12, 1988) (vehicle equipped with two upper beam headlamp systems would violate the impairment provision because it would exceed the upper beam maxima at H-V and 4D-V). 

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Richard Seoane 

at 4D-V. We consider the upper beam maxima as proper comparators because the Marking Light, like the upper beam, is designed to activate when no other cars are nearby.18 Just as upper beam headlamps are subject to maximum intensity limits, even though they are designed to turn off in the presence of oncoming traffic, the same concerns apply to forward-facing auxiliary lighting. 

You argue in your letter that the Marking Light will not glare other road users or mask any of the required signal lighting. You state that the Marking Light is disabled in the presence of oncoming traffic, so that its downward angle does not glare other drivers on a wet or shiny roadway. You also state that because the Marking Light is low to the ground and produces very little light above the horizontal plane of the headlamps, it cannot glare another driver or pedestrians. You state that because of these features, the Marking Light does not impair an oncoming driver’s ability to perceive the front turn signals. In a meeting with our office, you also indicated that the spotlamps on each side of the vehicle are generally not additive (combined). 

You also provided data on the intensity of the Marking Light (an iso-candela plot) based on on-vehicle measurements at a test laboratory. The photometric testing indicates that the Marking Light’s maximum intensity is 113,440 cd (at approximately four degrees down). You noted that the test setup resulted in higher estimated light intensities than what would be more accurately estimated by a goniometric component test conducted in a properly designed component lamp goniometry facility with appropriate stray light control. 

We believe that the Marking Light would violate the impairment provision because it would exceed—dramatically—the maximum permissible brightness of upper beams at 4D-V. This extreme intensity is a concern even if the Marking Light beam is aimed at a downward angle and the system is designed so that the light is disabled in the presence of oncoming and preceding vehicles, because it could still glare other motorists if the vision system does not correctly detect an oncoming or preceding vehicle and prevent the Marking Light from activating. This glare could happen, for example, if the vehicle crests the top of a hill when another vehicle is approaching, the vehicle encounters another vehicle at an intersection without detecting the other vehicle approaching from the side, or if the Marking Light reflects off wet pavement. 

We recognize that the photometric test setup led to overestimates of the Marking Light’s intensity. Nevertheless, the Marking Light is so intense that a more accurate estimate would likely still greatly exceed the upper beam maximum. We also note that the Marking Light’s intensity dramatically exceeds not only the upper beam maximum at 4D-V (12,000 cd), but also the maximum allowed for any individual upper beam headlamp (75,000 cd at H-V). This intensity presents a risk that other road users could be subject to significant glare. 

Conclusion 

I conclude that the Marking Light would be prohibited by the impairment provision in FMVSS No. 108 with respect to the Marking Light’s intensity at 4D-V.
18 FMVSS No. 108 S4 (upper beam defined as “beam intended primarily for distance illumination and for use when not meeting or closely following other vehicles”). 

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Richard Seoane 

If you have any further questions, please contact John Piazza of my staff at (202) 366-2992. 

Sincerely,
ADAM RAVIV
Adam Raviv Chief Counsel

Dated: 6/27/24
Ref: Standard No. 108

ID: aiam5501

Dear Mr. Daining: This responds to your letter about Federa requirements applicable to an 'on/off switch' for antilock brake systems (ABS). I apologize for the delay in our response. You stated that Chrysler Jeep owners disengage their ABS in response to the 'perceived degraded performance it offers on off-road situations.' You mentioned the possibility of designing a vehicle's gear system so that the ABS function is automatically disengaged when the vehicle is shifted into the four wheel drive-LO configuration. As explained below, while both manual and automatic ABS on/off switches are permitted under the current requirements, neither is required. By way of background information, the National Highway Traffic Safety Administration (NHTSA) is authorized under Title 49, Chapter 301 of the U.S. Code to issue FMVSSs that set performance requirements for new motor vehicles and new items of motor vehicle equipment. NHTSA does not approve or certify any vehicles or items of equipment, as is the practice in Europe. Instead, Chapter 301 establishes a 'self-certification' process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. The agency has used this authority to issue FMVSS No. 105, Hydraulic Brake Systems, which specifies requirements for hydraulic service brake and associated parking brake systems. This Standard does not contain any provision requiring or prohibiting ABS. Likewise, it does not contain any provision requiring or prohibiting either a manual or automatic ABS on/off switch. Accordingly, either type of switch is permitted under the standard, provided the vehicle complies with the standard both when the device is 'on' and when the device is 'off.' FMVSS No. 105 will continue to apply to multipurpose passenger vehicles (MPVs), notwithstanding the agency's recent adoption of FMVSS No. 135 Hydraulic Brake Systems, Passenger Car Brake Systems, which applies only to passenger car brake systems (60 FR 6411, February 2, 1995). Even though FMVSS No. 135 does not apply to MPVs, you should be aware that FMVSS No. 135 prohibits passenger cars from being equipped with ABS disabling switches. The agency stated in a July 1991 notice that 'such a switch could be left off when the ABS is needed, and that therefore, it would be more likely to be harmful than beneficial.' Please note that this prohibition does not become immediately effective, even for passenger cars, since manufacturers can continue to certify compliance to FMVSS No. 105 for five years after FMVSS No. 135 takes effect. If an automatic or manual ABS on/off switch were installed in a used vehicle, such a device must not 'make inoperative' the vehicle's compliance with FMVSS No. 105. Specifically, 49 U.S.C. 30122 prohibits a motor vehicle manufacturer, distributor, dealer or repair business from installing such a device if the installation 'makes inoperative' compliance with any safety standard. For instance, if a vehicle could only comply with the stopping distance or other service brake requirements in Standard No. 105 when the ABS is activated, then installation of the switch would serve to make inoperative compliance with the safety standard. I hope you find this information helpful. If you have any other questions, please contact Marvin Shaw of my staff at this address or by phone at (202) 366-2992. Sincerely, Philip R. Recht Chief Counsel;

ID: aiam3078

Dear Mr. Lyford: This responds to the questions you raised with Ms. Debra Weiner of m office when you telephoned on June 4, 1979, on behalf of your clients who intend to manufacture auxiliary gasoline tanks, to sell the tanks as part of a universal kit with all parts necessary for installation, and in some instances to install the tanks in vehicles. you inquired as to the meaning of the word 'integrity' as used in Federal Motor Vehicle Safety Standard (FMVSS) No. 301-75 (49 CFR 571.301-75) and the applicability of the standard to your clients' proposed activities. You also inquired as to the meaning of the phrase 'render inoperative' as used in section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act, as amended in 1974 (the Act) and its applicability to your clients' proposed activities.; The National Traffic and Motor Vehicle Safety Act, as amended in 1974 (the Act) authorizes the National Highway Traffic Safety Administration (NHTSA) to issue Federal Motor Vehicle Safety Standards (FMVSS's) applicable either to entire vehicles or to equipment for installation in vehicles. FMVSS 301-75, *Fuel System Integrity*, is a vehicle standard that applies to vehicles which use fuel with a boiling point above 32 degrees F. and which are (1) passenger cars or (2) multipurpose passenger vehicles, trucks or buses with a gross vehicle weight rating (GVWR) of 10,000 pounds or less, or (3) school buses with a GVWR greater than 10,000 pounds. The word 'integrity' as used in FMVSS 301-75, refers to the fact that compliance with the standard requires that fuel spillage from a vehicle subjected to a fixed or moving barrier crash not exceed the limits established by FMVSS 301-75, S5.5 and S5.6.; Since FMVSS 301-75 is only a vehicle standard and does not specif performance standards for fuel tanks, it does not directly apply to your clients' proposed manufacturing activities. However, as will be discussed later, it does apply when an auxiliary fuel tank is installed in a vehicle by either the manufacturer of the tank or other persons specified in the Act.; Despite the lack of a specifically applicable safety standard auxiliar fuel tanks must be designed and manufactured for safety. The defect responsibility provisions of the Act (sections 151-153) authorize the Secretary of Transportation (or his delegate the NHTSA Administrator) to make determinations as to whether items of motor vehicle equipment contain defects which relate to motor vehicle safety. If he finds that safety-related defect exists, he may compel the manufacturer of the equipment to remedy the defect and notify purchasers of the hazard. In addition, these provisions also require that a manufacturer who discovers a safety-related defect in his product notify the Secretary of Transportation (or NHTSA Administrator) and then provide notification and remedy to purchasers. Under section 108(a)(1)(D) and 109(A) of the Act, any person who fails to provide notification of or remedy for a safety defect is liable for a civil penalty of up to $1,000 per violation.; Since auxiliary gasoline tanks are items of motor vehicle equipment, a defined in section 102(4) of the Act, your clients as manufacturers of such equipment would be required to provide notification and remedy should their auxiliary gasoline tanks prove to be defective in design, materials, manufacture, or performance. (See 49 CFR Part 597).; FMVSS 301-75 would apply to your client's installation of auxiliar fuel tanks in new motor vehicles. Under section 108(a)(1)(A) and (b)(1) of the Act, new motor vehicles must comply with the safety standrds (sic) applicable to them until they are first purchased by someone, for purposes other than resale. The purchase is completed when the vehicle is delivered to the ultimate customer. Any person who, prior to the first sale of a vehicle for purposes other than resale, alters that vehicle by making more than minor finishing operations, is required by 49 CFR 567.7 to recertify the entire vehicle as complying with all safety standards applicable to it. Should a noncompliance be discovered as a result of an alterer's modification, the alterer would be liable for a civil penalty unless he or she could establish that he or she did not have actual knowledge of the noncompliance, and that he or she did not have reason to know in the exercise of due care that the vehicle did not comply (Section 108(b)(2) of the Act).; Under these provisions, your clients would be considered to be alterer if they installed an auxiliary fuel tank in a new vehicle prior to the vehicle's first purchase for purposes other than resale, and they would be required to recertify the vehicle as complying with applicable safety standards, including FMVSS 301-75. With respect to FMVSS 301-75, the effect of the alterer provisions is that not only must the original gasoline fuel system meet the performance requirements encompassed by the standard but that any auxiliary tank added by an alterer must meet them also.; It should also be noted that the defect responsibilities imposed b Section 151 *et seq*., mentioned earlier with respect to the defective design, composition, manufacture or performance of auxiliary tanks also apply to safety defects in the installation of such tanks in new vehicles. Installation defects include defects in the method and location of installation. Acting, as both manufacturers and installers of the tanks, your clients would be subject to responsibilities for safety defects stemming from both the production and installation of the tanks.; FMVSS 301-75 as well as the 'render inoperative' provisions of sectio 108(a)(2)(A) of the Act would apply to your clients' activities in installing auxiliary gasoline tanks in used vehicles. After the first sale of a vehicle for purposes other than resale, tampering with the vehicle (referred to here as a used vehicle) is limited by section 108(a)(2)(A). Specifically, the section provides:; >>>No manufacturer, distributor, dealer, or motor vehicle repai business shall knowingly render inoperative in whole or part, 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 ....<<<; The words 'render inoperative,' in the context of section 108(a)(2)(A) in essence prohibit certain listed entities and persons from knowingly removing, disconnecting or reducing performance of equipment or elements of design installed on a vehicle in accordance with applicable safety standards.; A listed person or entity found to have violated section 108(a)(2)(A would be liable for a civil penalty of up to $1,000 for each violation.; Should your clients begin producing auxiliary gasoline tanks they woul be encompassed by the term 'manufacturer' as that term is used in section 108(a)(2)(A) and defined in section 102(5) of the Act. Therefore, if your clients added an auxiliary gasoline tank to a used vehicle manufactured in accordance with FMVSS 301-75 and in the process knowingly reduced the performance of the fuel system originally installed in the motor vehicle, they would be deemed in violation of section 108(a)(2)(A). Such reduction of performance could occur for example, if the gasoline from the original system (a fuel system includes the filler pipe, tank, gasoline lines, fuel pump, carburetor, and engine) could be leaked through a rupture in the auxiliary tank and fuel lines, or if the design materials, construction, installation or location of the auxiliary tank and fuel lines made them more susceptible to rupture than the original fuel system.; I hope you will find this response helpful. Sincerely, Frank Berndt, Chief Counsel

ID: aiam4950

"Dear Mr. Martin: This is in regard to your letter of December 9, 1991 regarding school buses. Your three questions are addressed below. 1. (W)hat is the general rule to which states need to comply with regarding Federal school bus safety standards? What bus safety modifications would not be restricted by 15 U.S.C. 1392(d)? Section 103(d) of the National Traffic and Motor Vehicle Safety Act (the Safety Act, 15 U.S.C. 1392(d)) provides that: Whenever a Federal motor vehicle safety standard ... 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 ... any State or political subdivision thereof from establishing a safety requirement applicable to motor vehicles or motor vehicle equipment procured for its own use if such requirement imposes a higher standard than that required to comply with the otherwise applicable Federal standard. Section 103(d) preempts state requirements for school buses covering the same aspect of performance as an applicable Federal motor vehicle safety standard (FMVSS) that are different from the applicable FMVSS except to the extent that the requirements impose a higher level of performance and apply only to vehicles procured for the State's use. A state law imposing higher requirement would be preempted under 103(d) to the extent that the law requires all school buses manufactured for use in the state to comply with the law. The law would not be preempted to the extent that it applies to public school buses. The agency has previously interpreted the phrase 'vehicles procured for (the State's) own use' to include public school buses and school buses operated and owned by a private contractor under contract to transport children to and from public school. See, for example, February 20, 1987 letter to Mr. Martin Chauvin (copy enclosed). 2. Would Federal safety standards restrict a state from requiring safety belts on school buses? A state requirement that all school buses be equipped with safety belts regulates the same aspect of performance as the Federal standard for school bus occupant crash protection (FMVSS No. 222, School Bus Passenger Seating and Crash Protection) and would not be identical to that standard for large school buses (those with a gross vehicle weight rating (GVWR) over 10,000 pounds). FMVSS No. 222 requires school buses to provide passenger crash protection through a concept called 'compartmentalization.' Providing compartmentalization entails improving the interior of the school bus with protective seat backs, additional seat padding, and better seat spacing and performance. These interiors are intended to keep occupants in their seating area and protect them during a crash. FMVSS No. 222 requires the additional protection of safety belts at each passenger position in small school buses (10,000 pounds or less GVWR) because these buses experience greater force levels in a crash. A state requirement for safety belts on school buses would be identical to the level of performance required for small school buses, but would specify a different level of performance for large school buses. However, because the state requirement specifies a higher level of performance for large school buses than that required by FMVSS No. 222, Maine may require the installation of safety belts in school buses procured by the State or its political subdivisions, as long as the Federal requirements for compartmentalization are not compromised. 3. Could a school bus fleet modify the rear lighting configuration of their buses (8 light system) to reduce the potential for other vehicles rear-ending buses during poor visibility conditions, e.g., fog? ... The proposed change is to replace the white 8 inch back-up lights with 8 inch red sealed beam warning lights similar to the two at the upper level of the rear end of the bus. These would flash in an alternating criss-cross fashion when the bus is stopped loading or discharging students. The small white lights at the lowest level of the rear end of the bus would each be replaced with white, universal backup lights angled to also direct their beams at 45 degree angles out from the rear of the bus. The answer to your question is yes if the school district or its fleet contractor performs the modification itself. The National Traffic and Motor Vehicle Safety Act (the Safety Act, 15 U.S.C. 1381 et seq.) authorizes this agency to issue FMVSS applicable to new motor vehicles and new items of motor vehicle equipment. Section 108(a)(1)(A) of the Safety Act (15 U.S.C. 1397(a)(1)(A)) prohibits the sale for purposes other than resale of any new motor vehice or item of motor vehicle equipment unless it is in conformity with all applicable FMVSSs. After the first purchase of a vehicle in good faith for purposes other than resale, the only provision in Federal law that affects a vehicle's continuing compliance with an applicable safety standard is set forth in Section 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section provides that: No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or in part, any device or element of design installed on or in a motor vehicle ... in compliance with an applicable Federal motor vehicle safety standard. This provision does not regulate in any manner how a vehicle owner can modify his or her vehicle. I note, however, that this agency encourages vehicle owners not to tamper with their vehicle's safety equipment if the modification would degrade the safety of the vehicle. In addition, it is possible that the modifications you describe could be made by one of the named commercial entities without violating the 'render inoperative' provision. The modification you describe affects two requirements of FMVSS No. 108, Lamps, reflective devices, and associated equipment. FMVSS No. 108 requires buses, including school buses, to have at least one backup light meeting the photometric and height requirements of SAE Standard J593c, February 1968. If the small white lights at the lowest level of the rear end of the bus comply with these requirements, the vehicle would continue to conform with this requirement. Section S5.1.4 of FMVSS No. 108 requires school buses to have a system of either four red or four red and four amber signal lamps which conform to SAE Standard J887, July, 1964. The modification you describe would add an additional two red signal lamps to the existing eight light system. Section S5.1.3 of FMVSS No. 108 states that '(n)o additional lamp, reflective device or other motor vehicle equipment shall be installed that impairs the effectiveness of lighting equipment required by this standard.' It is our opinion that the addition of two red signal lamps would not violate this provision. I hope this information is helpful. If you have further questions, please contact Mary Versailles of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosure";

ID: NCC-230420-001 571.108 Angelina Twardawa Auxiliary Side Lamps Interpretation signed

April 16, 2025

U.S.Department of Transportation
National Highway Traffic Safety Administration
Office of the Chief Counsel
1200 New Jersey Avenue SE. Washington, DC 20590

Ms. Angelina Twardawa 4550 Gustine Ave
St. Louis, MO  63116
angelina@angiestrans.com 

Dear Ms. Twardawa: 

This responds to your letter, received December 5, 2022 in which you requested a letter of interpretation asking whether aftermarket auxiliary trifunctional side marker lights which illuminate red in the rear, amber in the side, and white in the front, and that attach to the rear of a 53-foot trailer on both sides are compliant with Federal Motor Vehicle Safety Standard (FMVSS) No. 108, Lamps, reflective devices, and associated equipment. We apologize for the delay in responding to your inquiry. Based on the information you provided in your letter, we have concluded that installing the device as described may conflict with FMVSS No. 108. However, an alternative color configuration should be permissible under that standard. 

Please note that our guidance below is based on our understanding of the specific information provided in your letter. 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. 

Background 

NHTSA is authorized by the National Traffic and Motor Vehicle Safety Act (Safety Act, 49 U.S.C. Chapter 301) to issue FMVSS that set performance requirements for new motor vehicles and new items of motor vehicle equipment. The Safety Act requires manufacturers to self-certify that their vehicles and equipment conform to all applicable FMVSS in effect on the date of manufacture.
NHTSA also investigates safety-related defects. After first purchase of a motor vehicle or item of motor vehicle equipment other than for resale, section 30122 of the Safety Act requires that a manufacturer, distributor, dealer, rental company, or motor vehicle repair business not knowingly make inoperative any part of a device or element of design installed on or in a motor vehicle or motor vehicle equipment in compliance with an applicable motor vehicle safety standard. This letter represents NHTSA's opinion concerning whether your design, as you describe it, would be permitted under FMVSS No. 108 and section 30122.

In your letter, you state that the device is a trifunctional light that attaches to the side of the rear guard of a 53-foot trailer on both sides with an open-ended connector. The lights have a red light designated at the rear, amber light designated at the side, and a white light designated at the front. You note that the piece that attaches to the trailer is rubber and flexible so it will not break, and that the device is stationary. You state the purpose of the device is to assist drivers with backing up, lane changes, and other maneuvers by providing increased visibility of the trailer at night. You ask whether the described design is permitted (both with regards to the device overall and the described lighting configuration), and if it is how far the devices can extend. 

FMVSS No. 108 specifies requirements for original and replacement lamps, reflective devices, and associated equipment, including for trailers. For auxiliary lamps, the primary restriction imposed by FMVSS No. 108 is by S6.2.1, which states that "[n]o additional lamp, reflective device, or other motor vehicle equipment is permitted to be installed that impairs the effectiveness of lighting equipment required by this standard." Additionally, both original equipment and aftermarket lighting can run afoul of the "make inoperative" provision in 49 U.S.C. § 30122. These prohibitions bar installation by a manufacturer, distributor, dealer, rental company, or motor vehicle repair business of lamps that would impair the effectiveness of required lighting, but do not apply to the owner of a vehicle. We note that whether there is an impairment is determined in the first instance by the manufacturer of the vehicle (or the entity installing the aftermarket lighting) when it is certified as compliant with FMVSS No. 108. 

Typically, the impairment determination is made on a case-by-case basis and looks at four main characteristics of the auxiliary lamp to analyze whether it impairs the effectiveness of required lighting. These are the brightness (photometric intensity), color, location, and activation pattern of the lamp.1 This list is not exhaustive and other considerations may be relevant to the analysis. NHTSA has long stated that highway traffic safety is enhanced by the familiarity of drivers with established lighting schemes, which facilitates their ability to instantly recognize the meaning the lamps convey and respond accordingly.2 Therefore, we have long interpreted the impairment provision to prohibit auxiliary lamps that are colors which are likely to cause confusion to other road users.3 Additionally, auxiliary lamps must be located such that they would not interfere or be confused with the lamps required by our standards. For example, we have stated that two auxiliary 

1 This letter is limited to the information provided in your request. Your request did not state the activation pattern or intensity of the device, which can be relevant to determining if a device causes impairment. For the purposes of this letter, we assume without finding that these aspects of your device do not cause impairment. The following information is provided for your reference regarding these elements. Regarding activation pattern, NHTSA interprets FMVSS No. 108 to require that all auxiliary lamps be "steady burning," with the sole exception being auxiliary lamps that supplement required lamps that flash, such as turn signals. Letter to Paul Schaye (Sept. 9, 2019), available at htqJs://www.nhtsa.gov/interpretations/571108-ama-schaye-front-color-changing-light. Regarding intensity, NHTSA interprets the impairment provision to prohibit auxiliary lamps that are so bright as to obscure or distract from a vehicle's required lamps. For example, NHTSA has in the past stated that supplemental lighting can impair the effectiveness of the required lighting if it is so intense that it glares other road users or masks required signal lamps. See Letter to Rusty Riggin, Aug. 2, 2002, available at htqJs://www.nhtsa.gov/interpretations/24179ztv, (explaining that a supplemental rear cornering lamp could violate the impairment provision if it was so intense that it "create[d] distracting glare"). Letter to Mark Wallach (Oct. 17, 2006) available at htqJs://www.nhtsa.gov/interpretations/wallach3.
2 Letter to Robert Clarke (July 28, 2005), available at htqJs://www.nhtsa.gov/interpretations/gID0255l3.
3 As an example, for auxiliary lamps located on the front of vehicles, these colors include red, which could be confused for a taillamp or stop lamp, and green, which typically conveys the message that one may proceed forward and could therefore impair required lighting that indicates caution. Letter to Paul Schaye (Sept. 9, 2019), available at htqJs://www.nhtsa.gov/interpretations/571108-ama-schaye-front-color-changing-light See also, Letter to Kerry Legg (Oct. 19, 2006), available at htqJs://www.nhtsa.gov/interpretations/leggl.

lamps located next to the three-lamp trailer identification lamp cluster would detract from the purpose of the cluster.4    '

For lighting relevant to your inquiry, FMVSS No. 108 requires that trailers have two amber side marker lamps as far to the front as practicable and two red side marker lamps as far to the rear as practicable. Trailers 30 feet or longer must also have amber intermediate side marker lamps and reflex reflectors on each side located at or near the midpoint between the front and rear side marker lamps.5, 6 

Discussion 

We now turn to your inquiry. Your lamp is not required equipment, and you correctly observe that it is auxiliary or supplemental lighting.7 Therefore, we turn to the question of impairment and look to the characteristics discussed. The factors which appear most relevant to your inquiry are the location and color of the lamps, which we analyze together. Due to the color and location of the lamp as described in your letter, it is likely to impair the effectiveness of the side marker lamps required to be installed on trailers by FMVSS No. 108, and, if installed by you or another entity subject to the "make inoperative" prohibition as aftermarket equipment, could make inoperative lighting required by FMVSS No. 108.8 However, an alternative color scheme would be permissible under FMVSS No. 108. 

Regarding side marker lamps, FMVSS No. 108 requires that intermediate side marker lamps be amber, and rear side marker lamps be red. Your design notes that your device will be mounted at the rear and that the side of the device will have amber lights. Therefore, in driving conditions
with poor visibility, such as at night or in heavy weather, your device may impair the effectiveness of the required intermediate side marker lamps by confusing nearby drivers about whether it indicates the rear or middle of the trailer, which could lead to unsafe driving decisions. 

4 Letter to Robert Clarke (July 28, 2005), available at htt;ps://www.nhtsa.gov/inter_pretations/gf00255l3.
5 We also note that S6.l.3.l of FMVSS No. 108 requires that each lamp, reflective device, and item of associated equipment must be securely mounted on a rigid part of the vehicle. The purpose,of this requirement is to ensure that lamps and reflectors do not sway in the wind on rigid hinges or flexible mud flaps when the vehicle is in motion. Letter from Frank Burndt to Dietmar K. Haenchen, (date unavailable), available at https://www.nhtsa.gov/inter_pretations/aiam3320. S6.l.3.1 is organized in S6.1 ofFMVSS No. 108, which contains requirements applicable to required lamps, reflective devices, and associated equipment. Although this provision does not explicitly apply to auxiliary lamps, an auxiliary device that is not securely mounted to a rigid part of the vehicle may impair the effectiveness ofrequired lighting because the motion of the light could distract drivers.  We have assumed for the purposes of this letter that your device is securely mounted to a rigid part of the vehicle and encourage you to ensure that this is the case.
6 49 CFR 571.108 Table 1-b. 49 CFR 393.11, which you referenced in communication with my staff, which requires commercial motor vehicles operated by motor carriers to be equipped with such lighting, contains similar specifications for color and placement of side marker lamps.
7 Your request describes your device as a "side marker lamp." Side marker lamps are a type of required equipment under FMVSS No. 108. Because your device is not required lighting, to avoid confusion this letter does not refer to your device as a side marker lamp.
8 Section 30122 applies to any "manufacturer, distributor, dealer, rental company, or motor vehicle repair business." We assume, for the purposes of this letter, that you are subject to this provision. 

Our opinion is based on the location and color of the lights as described in your letter. An alternative color scheme, with a red light facing the side in place of the amber light, is unlikely to have the same risk of impairing the effectiveness of the side marker lamps because it would
correspond to the color required for the required side marker lamps installed on each side as far to the rear as practicable, close to where you plan to install the device. We also encourage you to consider designs which mitigate any risk that a forward-facing white light could be perceived as a headlamp by other road users. 

Finally, you inquired about how far out the devices may extend from the trailer. NHTSA's regulations do not contain requirements specific to this question. Vehicle width is regulated by the Federal Highway Administration, who's regulation states that no State shall impose a width limitation of more or less than 102 inches (except Hawaii) for vehicles operating on the National Network.9 Five items are excluded regardless of how far they extend beyond the exterior of vehicles; rear view mirrors, turn signal lamps, handholds for cab entry/egress, splash and spray suppressant devices, and load induced tire bulge. Other excluded devices are: all non-property carrying devices or components at the front of a semitrailer or trailer, devices that do not extend more than 3 inches beyond each side or the rear of a vehicle, devices needed for loading or unloading that do not extend more than 24 inches beyond the rear of the vehicle, and aerodynamic devices that do not extend more than 5 feet beyond the rear of a vehicle, provided they have neither the strength, rigidity nor mass to damage a vehicle that strikes a trailer so equipped from the rear and provided also that they do not obscure tail lamps, turn signals, marker lamps, identification lamps, or any other required safety features, such as hazardous materials placards or conspicuity markings.10 

We also note that, because it is an item of motor vehicle equipment subject to the requirements of the Safety Act, it must be designed free from defects regarding motor vehicle safety. Additionally, truck tractors and trailers operated commercially in interstate commerce are subject to the regulations of the Federal Motor Carrier Safety Administration (FMCSA). Finally, States may have laws applicable to certain motor vehicle lighting. We are unable to advise you on those laws, but you should ensure your system complies with any and all applicable State laws.

We hope you find this information helpful. If you have further questions, please contact Eli Wachtel of my staff at (202) 366-2992.

Sincerely,

Peter Simshauser Chief Counsel

Dated: 4/16/25
Ref:  Standard No. 108
 

9 23 CFR 658.15.
1°FHWA Vehicle Size and Weight Q&A, available at https://ops.fhwa.dot.gov/freight/sw/fags/qa.cfin?categ01y=8. For
more excluded devices, see 23 CFR 658.16 and Appendix D to 23 CFR 658.

ID: 571.108 -- AMA -- Schaye--front color changing light

Paul Schaye
CEO, Pedestrian Safety Solutions
245 Park Avenue, 41st Floor
New York, NY 10167

Dear Mr. Schaye:

This responds to your letter requesting an interpretation of whether your auxiliary lamp, the Auto Motion Alert (“your product”), is permissible under Federal Motor Vehicle Safety Standard (FMVSS) No. 108, Lamps, reflective devices, and associated equipment.  Because your product would be installed as aftermarket equipment, not as original equipment, and would not replace original equipment, and because FMVSS No. 108 applies only to equipment installed as original equipment or that replaces original equipment, we have interpreted your request as asking whether the installation of your product is permissible under the “make inoperative” provision of the National Traffic and Motor Vehicle Safety Act of 1966 (the Safety Act).  The Safety Act prohibits most automotive businesses from installing aftermarket lighting equipment if doing so would take the vehicle out of compliance with FMVSS No. 108.  For auxiliary lamps, the primary restriction imposed by FMVSS No. 108 is that the lamps cannot impair the effectiveness of a vehicle’s required lighting equipment.

We have tentatively concluded that your product is unlikely to impair the effectiveness of required lighting equipment, and is therefore unlikely to violate the “make inoperative” provision.  However, we wish to emphasize that the existence of impairment would depend on the context in which your lamp is used, and thus must be determined on a case-by-case basis.  It is the responsibility of the business installing your product to determine whether doing so constitutes a “make inoperative” violation. We explain our reasoning below.

Description of your product
You describe your product as a lamp that is designed to be installed above a vehicle’s front license plate using the two top mounting screws.  You state that the purpose of installing the lamps on a vehicle is to communicate to road users ahead of the vehicle whether the vehicle is decelerating, accelerating, or maintaining a constant speed. You state that your product consists of a strip of amber and white LEDs, although you do not provide the exact photometric intensity.  Either the white or amber LEDs are activated, depending upon the underlying condition.  You state that the white LEDs are activated and steadily burn while the vehicle is accelerating or travelling at a constant speed, and that the amber LEDs are activated and steadily burn while the vehicle is decelerating or stopped.  The LEDs are actuated by a microcontroller that detects the vehicle’s acceleration using internal accelerometers.  We also understand, based on our communications with you, that the brightness of the LEDs, the threshold levels of acceleration or deceleration activating the LEDs can be controlled through software, although it is our understanding that the product will be sold as a sealed unit that is not adjustable by the end user. You state that, although the LEDs activate independently of other vehicle systems (including the braking system), your product is powered by either a direct connection to the vehicle’s battery, or a 12-volt DC wire supply that is live when the vehicle is turned on.  The exterior housing consists of a weather-resistant polymer enclosure with gasket type seal. 

Applicable Requirements
Because you state that you intend to sell your product aftermarket, the primary potential restriction on its installation is the Safety Act’s “make inoperative” provision. 49 U.S.C.           § 30122.  The “make inoperative” provision states that manufacturers, distributors, dealers, rental companies and motor vehicle repair businesses may not “knowingly make inoperative any part of a device or element of design installed on or in a motor vehicle or motor vehicle equipment in compliance with an applicable motor vehicle safety standard” promulgated under the Safety Act.  This means that the businesses subject to the “make inoperative” provision would be prohibited from installing your product on a vehicle if doing so would take the vehicle out of compliance with any FMVSS.  The “make inoperative” provision does not apply vehicle owners, and these owners are not precluded from modifying their vehicle by NHTSA’s statutes or regulations.  State and local laws, however, may impact whether an owner may use a vehicle they have modified in a particular jurisdiction.

NHTSA considers the installation of an aftermarket lamp to violate the “make inoperative” provision if the installation of the same lamp as original equipment would violate FMVSS No. 108.[1]  As a non-required (“auxiliary”) lamp, your product is not required to meet any of the performance requirements in FMVSS No. 108 that it would need to meet if it were installed as original equipment.[2]  However, your product would be prohibited under FMVSS No. 108 (and thus, would violate the “make inoperative” provision) if it would “impair[] the effectiveness of lighting equipment required by this standard.” FMVSS No. 108, S6.2.1.    

Because the existence of impairment is, in part, a function of the context in which an auxiliary lamp is used, impairment must be determined on a case-by-case basis.  If a business subject to the “make inoperative” provision installs an aftermarket auxiliary lamp, that entity is responsible for determining whether doing so causes impairment.  If NHTSA determines that a business to which the “make inoperative” provision applies has impaired the effectiveness of required lamps, that business would be subject to a fine of up to $22,329 per violation.[3]  

Discussion
Based on the information you provided in your interpretation request, we have tentatively concluded that your product, if configured and installed in conformance with the restrictions described in letter, is unlikely to impair the effectiveness of a vehicle’s required lighting, and its installation on a vehicle would be unlikely to constitute a “make inoperative” violation.  There are four aspects of auxiliary lamps that are relevant to impairment: brightness (i.e., photometric intensity), color, location, and activation pattern.  What follows is a brief explanation of NHTSA’s safety concerns for each of these characteristics, along with examples of instances in which the agency would consider an auxiliary lamp to violate the impairment prohibition.  It should be noted that determining whether an auxiliary lamp impairs the effectiveness of required lamps involves a holistic assessment of the context in which the auxiliary lamps are used, and the examples provided are not exhaustive.  Thus, although this letter discusses these four characteristics separately, they should not be considered in isolation, nor should they be considered an exhaustive list of all the considerations that should be taken into account when making an impairment determination.

Brightness (Photometric Intensity)
NHTSA interprets the impairment provision to prohibit auxiliary lamps that are so bright as to obscure or distract from a vehicle’s required lamps.  For example, NHTSA has in the past stated that auxiliary lamps that were so bright as to “mask” adjacent required turning signal lamps would be prohibited due to impairment.[4]   While you do not state the precise brightness of your product, you state that its brightness “is limited and so would not impair or mask the vehicle’s headlamps or turn signals.”  Although the extent to which your product would interfere with a vehicle’s required lighting may vary depending on the design and performance of a particular vehicle’s required lamps, we do not believe your product would impair the effectiveness of a vehicle’s required lamps on the basis of brightness if its photometric intensity is sufficiently limited such that your product’s LEDs are noticeably dimmer than the vehicle’s required head lamps and front turn signal lamps.

Color
NHTSA interprets the “impairment” provision to prohibit auxiliary lamps that are colors the agency believes are likely to cause confusion to other road users.  For auxiliary lamps located on the front of the vehicle, colors that could cause confusion include red (which could be confused for a tail lamp), green (which could be confused for a traffic signal), and blue (which could be confused for a law enforcement vehicle).  By contrast, we have consistently said that amber and white lamps are permissible on the front of the vehicle.[5]  Because your product illuminates as either amber or white, depending on the underlying condition, we do not believe your product would impair a vehicle’s required lamps on the basis of color.

Location
NHTSA interprets the “impairment” provision to prohibit auxiliary lamps that are mounted in locations that cause them to interfere with the ability of a vehicle’s required lamps to achieve their purpose. For example, NHTSA has stated in the past that auxiliary lamps placed too close to FMVSS No. 108-compliant identification lamps would be prohibited because they may confuse other road users.[6]  The agency has long maintained that highway traffic safety is enhanced by the familiarity of drivers with established lighting schemes, which facilitates their ability to instantly recognize the meaning the lamps convey and respond accordingly. Therefore, any auxiliary lighting on the front of a vehicle must be located such that it would not interfere or be confused with other required lamps.  Your product is designed to be no wider than a license plate.  In the case where a license plate holder is mounted at the centerline of the vehicle at a lower mounting height than the vehicle’s required lamps, we think your product would, in most cases, be unlikely to interfere with the required lamps’ ability to achieve their function based on proximity.  However, we note that if a vehicle’s front license plate were located somewhere other than the centerline of the front bumper, and especially if it were located near a vehicle’s required lamps, it would be likely that the installation of your product on the front license plate holder would cause impairment.  Our determination in this letter that your product would be unlikely to impair the effectiveness of required lamps on the basis of mounting location assumes that your product is mounted on front centerline of the vehicle.  If your product were mounted somewhere other than the front centerline of the vehicle, we believe that it would be more likely to impair the effectiveness of the vehicle’s required lamps.

Activation Pattern
NHTSA interprets FMVSS No. 108 to require that all auxiliary lamps be “steady burning,” with the sole exception being auxiliary lamps that supplement required lamps that flash, such as turn signals.[7]  While this requirement has been relatively straight-forward to apply in the past, the introduction of new, programable lighting devices (such as your product) that are intended to communicate driver intent to other road users, has convinced the agency that it is necessary to clarify the meaning of “steady burning.”  To this end, we are clarifying here that the requirement that auxiliary lamps be steady burning does not mean that an auxiliary lamp is prohibited from being activated or deactivated automatically.  Rather, it means that the lamp must be steady burning when activated, and that the event that triggers its activation or deactivation (in this case, the vehicle’s rate of acceleration or deceleration exceeding a certain minimum threshold) cannot be so frequent or random that the lamp would distract or confuse other road users.  For example, a lamp that activated and deactivated on an extremely short time interval due to sensitivity to slight changes in the underlying conditions, would not be considered steady-burning.[8]  More traditional examples of lamps that are not steady-burning include, but are not limited to, strobes and turn signals.  By contrast, an auxiliary lamp that gradually changes in intensity based on ambient lighting conditions may be considered steady burning.[9] 

We have determined that your product would likely be considered steady burning because the event that triggers the activation of the LEDs—the deceleration of the vehicle—is likely not something that occurs so frequently or randomly that it would cause your product to appear to flash, which could confuse or distract other road users.  We note that this determination rests on the assumption that your product’s accelerometer is calibrated not to be overly sensitive to small changes in acceleration.    

We acknowledge that this interpretation supersedes some of our prior, more restrictive interpretations of the concept of “impairment.”  In particular, this letter specifically supersedes our previous interpretation concluding that all auxiliary lamps used to communicate “non-standard signals” (i.e., information other than what is communicated by required lamps) to other drivers would categorically impair the effectiveness of a vehicle’s required lamps.[10]  We reiterate, however, that auxiliary lamps may not be used to communicate non-standard signals (or, in fact, any signals) if doing so impairs the effectiveness of required lighting. 

Other Considerations
You should be aware that, even if your product is permissible under FMVSS No. 108 and the “make inoperative” provision, it is possible that State and local laws or restrictions may apply to your product. You may wish to consult the State and local transportation authorities in the areas you intend to market your product to make sure it is permissible under these laws. 

Finally, regardless of whether your product is subject to the restrictions of FMVSS No. 108 or the “make inoperative” provision, please be aware that if you or this agency finds your product to contain a safety-related defect after you market the product, you are responsible for conducting a notice and recall campaign as required under 49 U.S.C. §§ 30118-30120.

If you have further questions, please contact Daniel Koblenz of my staff at 202-366-2992.

Sincerely,

Jonathan C. Morrison
Chief Counsel

Dated: 9/9/19

Ref: FMVSS No. 108

[1] E.g., Letter to Timothy C. Murphy (Nov. 1, 2004), available at https://isearch.nhtsa.gov/files/GF006332.html.

[2] We note that auxiliary lamps that use plastic optical materials must comply with S14.1.2, and are subject to various other minor restrictions that are not relevant here.

[3] See 49 CFR part 578.

[4] E.g., Letter to Mark Wallach (Oct. 17, 2006), available at https://isearch.nhtsa.gov/files/Wallach.3.htm.

[5] E.g., Letter to Anthony M. Cooke (Oct. 19, 2006), available at https://isearch.nhtsa.gov/files/Legg1.htm.

[6] E.g., Letter to [REDACTED] (Jan. 21, 2004), available at https://isearch.nhtsa.gov/files/GF007705.html.

[7] Prior to 2007, FMVSS No. 108 included an explicit requirement that, with the exception of certain types of required lamps (e.g., turn signal lamps), all lamps on a vehicle, including auxiliary lamps, must be steady burning.  In 2007, NHTSA implemented an administrative reorganization of FMVSS No. 108 which, among other things, converted the blanket “steady burning” requirement (and its exceptions) into individual activation requirements for each type of required lamp.  See 72 FR 68234 (Dec. 4, 2007).  Although the reorganized rule no longer includes a blanket “steady burning” requirement, NHTSA stated in the preamble to the reorganized rule that its “rewrite of FMVSS No. 108 is considered administrative in nature because the standard’s existing requirements and obligations are not being increased, decreased, or substantively modified.” Moreover, NHTSA continues to believe that flashing auxiliary lamps would impair the effectiveness of required lamps by distracting or confusing other road users.

[8] E.g., Letter to Timothy C. Murphy (Nov. 1, 2004), available at https://isearch.nhtsa.gov/files/GF006332.html.

[9] E.g., Letter to Ian Goldstein (July 21, 1998), available at https://isearch.nhtsa.gov/files/18164.ztv.html.

[10] E.g., Letter to Kerry Legg (Feb. 21, 2008), available at https://isearch.nhtsa.gov/files/07-001583as.htm.

ID: 571.108--NCC-230201-001 LED Headlights_ M. Baker

February 13, 2024

Mr. Mark Baker, B.S.E.E. Soft Lights

9450 SW Gemini Drive PMB 44671

Beaverton, OR 97008

mbaker@softlights.org

Dear Mr. Baker:

This responds to your letter and email dated June 27, 2021 and October 31, 2021, respectively, regarding the legal status and safety of motor vehicle headlamps that use light-emitting diode (LED) technology as the light source. Please note that our answer below is based on our understanding of the specific information provided in your letter and email.

You ask about the “legality of LED headlights.” You state your belief that Federal Motor Vehicle Safety Standard (FMVSS) No. 108 does not regulate “peak luminance, absolute spectral power distribution or flicker” and that the standard “only applies to spherical emitters such as tungsten- filament and gas-discharge and is not applicable to non-uniform luminance flat-source emitters such as LED chips.” You ask whether it is “NHTSA’s position that FMVSS No. 108 is only applicable to uniform luminance emitters which can be regulated by setting maximums for luminous intensity without the need of setting peak luminance maximums” and whether “NHTSA [has] approved the use of spatially heterogeneous visible radiation for use as the light source used in vehicle headlights.” You state your concerns about adverse health impacts due to the performance characteristics of LEDs, such as high peak luminance, high-color temperature, high-energy blue wavelength light, and flicker. You request NHTSA’s opinion about the “sufficiency” of FMVSS No. 108 regarding these health concerns.

We understand you to use “uniform luminance emitters” to refer to filament (halogen/tungsten) and high-intensity discharge (HID) light sources, and “non-uniform” or “heterogenous emitter” to refer to LED light sources. We therefore understand you to be asking whether LEDs are legal as a light source in motor vehicle headlamps under FMVSS No. 108, and, if they are legal, what is NHTSA’s position on the safety of LED light sources in headlamps with respect to “eye safety, mental safety, and visual performance.”

Background

NHTSA is authorized by the National Traffic and Motor Vehicle Safety Act (Safety Act, 49 U.S.C. Chapter 301) to issue FMVSS that set performance requirements for new motor vehicles and new items of motor vehicle equipment. The Safety Act requires manufacturers to self-certify that their vehicles and equipment conform to all applicable FMVSS in effect on the date of manufacture. NHTSA also investigates safety-related defects.

FMVSS No. 108, “Lamps, reflective devices, and associated equipment,” applies to “[p]assenger cars, multipurpose passenger vehicles, trucks, buses, trailers (except pole trailers and trailer converter dollies), and motorcycles” and covers, among other things, “original and replacement lamps, reflective devices, and associated equipment” for motor vehicles. The standard specifies performance requirements for headlamps. The most common types of headlamps are integral beam (S10.14) and replaceable bulb (S10.15, S11) headlamps.

NHTSA has stated that LED light sources are permitted as part of an integral beam headlamp if they are wired in series such that a failure of one LED would cause all the LEDs to cease functioning, and they otherwise comply with all relevant FMVSS.1 Paragraph S4 of FMVSS

No. 108 defines an integral beam headlamp as “a headlamp … comprising an integral and indivisible optical assembly including lens, reflector, and light source, except that a headlamp conforming to paragraph S10.18.8 or paragraph S10.18.9 may have a lens designed to be replaceable.” The standard does not contain performance requirements for a light source that is part of an integral beam headlamp, but instead specifies performance requirements for the complete headlamp. These include (among other things) photometry, through minimum and maximum candela at specified test points,2 color, which must remain within specified boundaries,3 and that the headlamp be steady burning.4

While LED light sources that are part of an integral beam headlamp are permitted as noted above, no LED light source is currently permitted to be used in a replaceable bulb headlamp. FMVSS No. 108 contains specific requirements for the replaceable light sources (i.e., bulbs) used in replaceable bulb headlamps. These requirements are intended to support light source interchangeability. Paragraph S11 of the standard requires that “[e]ach replaceable light source must be designed to conform to the dimensions and electrical specifications furnished with respect to it pursuant to part 564 of this chapter[.]”5 Part 564 requires that replaceable bulb manufacturers submit to NHTSA for review and acceptance various design specifications for the bulb. If accepted, this design information is then placed in a publicly available docket to facilitate the manufacture and use of those light sources. As of the date of this letter, no submission that includes LEDs as the light source for a replaceable bulb headlamp has been listed in the docket. Therefore, no LED replaceable light source may be used in a replaceable bulb headlamp.

Discussion

Pursuant to FMVSS No. 108, paragraphs S4 and S10.14, LEDs are allowed to be used as a light source in integral beam headlamps as long as the headlamp conforms to all applicable headlamp requirements in FMVSS No. 108. However, LEDs are not currently permitted in a replaceable bulb headlamp. Nevertheless, illegal LED headlamp replaceable light sources may be available for purchase on the internet, and although these lights do not conform to the requirements of FMVSS No. 108, some consumers purchase and install these LED light sources in their replaceable bulb headlamps. While NHTSA regulates the manufacture and sale of light sources, it generally does not regulate the modifications individuals make to their own vehicles. It is therefore left to State law to address installation of an LED replaceable light source in a headlamp.

FMVSS No. 108 does not directly regulate what you describe as peak luminance as measured in nits or the spectral power distribution of the headlamp light source. However, this is indirectly regulated through the headlamp performance requirements, such as the photometry and chromaticity requirements. Additionally, flicker is regulated through the requirement that lower beam headlamps be steady burning. We also note that, although FMVSS No. 108 requires that the light emitted by headlamps be white, the permissible boundary of white includes colors that may be perceived by the human eye as white with a yellow tint and white with a blue tint.6

In your communications, you raise concerns about the health impacts of LED headlamps. We are aware of concerns raised about possible adverse effects of certain LED devices, particularly as used in street lighting that emits excess blue light.7 NHTSA’s focus is on automotive safety, but the agency recognizes that separate expertise resides in sister agencies that are health-focused, such as the Food and Drug Administration.

I hope this information is helpful. If you have any further questions, please feel free to contact Eli Wachtel of my staff at this address or at (202) 366-2992.

Sincerely,
 

John Donaldson
Acting Chief Counsel

1 Letter from Stephen Wood, Acting Chief Counsel, NHTSA, to Takayuki Amma, Manager, Koito Manufacturing Co. (Dec. 21, 2005). Letter from O. Kevin Vincent, Chief Counsel, NHTSA, to Junichi Hasegawa, Stanley Electric Co. (Apr. 8, 2013). Interpretation letters are available on NHTSA’s online interpretations database at https://www.nhtsa.gov/nhtsa-interpretation-file-search.

2 Photometry requirements for headlamp systems can be found in FMVSS No. 108, Tables XVIII and XIX.

3 See FMVSS No. 108, Table I-a (headlamp color). Chromaticity requirements are pursuant to FMVSS No. 108 S14.4.

4See FMVSS No. 108 Tables I-(a and c). NHTSA has stated that “steady burning” means “light that is essentially unvarying in intensity.” See Letter from Frank Berndt, Chief Counsel, NHTSA, to United Sidecar Association, Inc. (Feb. 9, 1982). A device may fail to meet this requirement where the driver “would not see a signal that was consistent or reliable in its meaning.” See Letter from Paul Jackson Rice, Chief Counsel, NHTSA, to Bob Abernathy, Idea’s Inc. (Sept. 7, 1990) (applying steady burning in a taillamps context). In the context of a modulating motorcycle headlamp, we have stated that “there is no failure to conform if the modulating light from the lamp is perceived to be a steady beam.” Letter from John Womack, Acting Chief Counsel, NHTSA, to Joe De Sousa (March 10, 1994).

5 See Letter from John Womack, Acting Chief Counsel, NHTSA, to Nancy Tavarez, Beitrix Industries (Aug. 30, 1995) (clarifying application of Part 564 to replaceable headlamp bulbs).

6 Letter from Frank Seales, Jr., Chief Counsel, NHTSA, to Richard Hodson, (July 4, 2000) (stating that “SAE J578c defines white by blue, yellow, green, red, and purple boundaries within a chromaticity diagram. Thus, it is possible to design a headlamp that emits a light that approaches the blue boundary and is perceived as having a blue tint but which nevertheless remains within the boundaries that define "white." These headlamps would comply with the color requirements of Standard No. 108.”).

7 See “AMA adopts guidance to reduce harm from high intensity street lights,” American Medical Association, June 14, 2016, available at https://www.ama-assn.org/press-center/press-releases/ama-adopts-guidance-reduce-harm-high- intensity-street-lights.

ID: aiam3852

Dear Mr. Nakaya: This responds to your letter dated January 20, 1984, concerning Federa Motor Vehicle Safety Standard (FMVSS) No. 101, *Controls and Displays*. You asked whether the standard would allow 'a secondary, redundant control placed in the rear seat area facilitating operation of the heating/ventilation and audio system functions by rear seat passengers.' As explained below, the answer to your question is yes.; By way of background information, the National Highway Traffic Safet Administration (NHTSA) does not pass approval on the compliance of any vehicle or equipment with a safety standard before the actual events that underlie certification. Under the Vehicle Safety Act, it is your responsibility as a manufacturer to determine whether your vehicles and equipment comply with all applicable safety standards and regulations, and to certify your products in accordance with that determination. The following interpretation only represents the agency's opinion based on the information provided in your letter.; Your letter indicates that controls for the heating and ventilatio unit would be placed in the rear seating area. You stated that these controls would be 'redundant' and 'secondary.' NHTSA assumes that there will be additional controls for the various functions of the units that are operable by and visible to the driver of the vehicle which meet all applicable requirements of Standard No. 101.; Section 5.2.1 requires identifications of any hand-operated contro listed in column 1 of Table 1 of that section to be visible to the driver. Listed in column 1 are 'Heating and/or Air Conditioning Fan,' and 'Heating and Air Conditioning System.'; You asked about illumination requirements in section 5.3 of FMVSS No 101 that might apply. Again, this section is intended to regulate the controls and displays operable by and visible to the driver, not the controls located in the rear seating area.; In requiring properly located and effectively identified controls an displays under FMVSS No. 101, the agency sought to reduce the safety hazards caused by the diversion of the driver's attention from the road. Locating secondary controls for passengers in the rear seating area for the heating and ventilation system would not distract the driver from the operation of the motor vehicle. The identification and illumination requirements of sections 5.2 and 5.3 were intended to apply only to the controls operable by and visible to the driver.; You should be aware, however, that section 5.3.3 of FMVSS No. 10 provides that '(t)he intensity of any illumination that is provided in the passenger compartment when and only when the headlights are activated shall also be variable in a manner that complies with this paragraph.' This section applies to all illumination in the passenger compartment that is dependent on activation of the headlights regardless of whether it shines upon a control display, to enable drivers to reduce the glare in the passenger compartment. Items such as radios and clocks which are not regulated by the location and identification requirements of FMVSS No. 101 are subject to the variable intensity requirements of section 5.3.3 if illuminated when, and only when, the headlights are activated. If the controls located in the rear seating area that operate the heating and ventilation unit are illuminated in this way, the standard requires that the light intensity for such controls must be continuously variable as described in section 5.3.3. You should further note that where you provide a control for the illumination intensity, section 5.1 of FMVSS No. 101 requires that it be operable by the driver, and its identification visible to the driver. We interpret this section to require at least one such control to be operable by and its identification visible to the driver. If a manufacturer separately meets the requirement of S5.1 by a properly located and identified control, additional controls that are added voluntarily by the manufacturer are not prohibited.; You indicated in your letter that Mazda is considering placin secondary controls for the audio system in the rear seating area. Controls and displays for audio systems are not regulated by FMVSS No. 101. The location and identification of these controls and displays are left to the discretion of the manufacturer. Once again, however, if the controls are illuminated when, and only when, the headlights are activated, then the same analysis discussed above applies. At least one control for the illumination intensity must be operable by the driver, with its identification visible to the driver.; In conclusion, FMVSS No. 101 does not prohibit placing the secondar controls for the heating and ventilation unit and audio system in the rear seating area. We would like to point out that there are other safety standards which may apply to your proposal that you should consider when you design these features for your automobiles, such as FMVSS No. 201, *Occupant Protection in Interior Impact*.; Sincerely, Frank Berndt, Chief Counsel

ID: 571.108--HELP System--Powers

Mr. Stephen T. Powers

Emergency Safety Solutions, Inc. (ESS)

825 Town & Country Lane

Houston, TX 77024

Dear Mr. Powers:

This letter responds to your request for an interpretation of whether your company’s product, the Hazard Enhanced Lighting Package (HELP) system, would be permitted under Federal Motor Vehicle Safety Standard (FMVSS) No. 108, Lamps, reflective devices, and associated equipment.  As explained below, our answer is yes, but only if the product is automatically activated following a crash that disabled the vehicle on which it is installed, or if manual activation of the system is restricted to when the vehicle is not moving and the parking brake is engaged.

By way of background, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment.  Instead, manufacturers are required to self-certify that their products conform to all applicable FMVSS that are in effect on the date of manufacture, before the product can be offered for sale. Manufacturers must also ensure their products are free of safety-related defects.  This letter represents NHTSA’s opinion concerning whether your product would be permitted under FMVSS No. 108.  It is not an approval of your product, nor is it an endorsement of the safety claims made in your initial interpretation request and supplemental submission.

Description of the HELP system

ESS describes the HELP system as an “added functionality” to the vehicle’s turn signal[1] which causes the lamps to flash at an accelerated rate of between 2-6 hertz to create “a strobing effect.”  According to ESS, this function could be activated in two ways: automatically when the vehicle is in “a significant crash,” or manually by pressing the hazard button while the hazard warning system is active and the vehicle is stopped.  In ESS’s supplemental submission, it clarified that, once the HELP system is manually activated, pressing the hazard button would switch the vehicle back to the hazard warning system, and pressing the hazard button again would turn both systems off.  ESS states that if the vehicle starts moving while the HELP system is activated, the system will deactivate, but does not specify whether this deactivation would be in the form of switching to the hazard warning system, or both systems deactivating.  ESS states that the system would use the vehicle’s required turn signal lamps, and that  the lamps would continue to comply with photometric and other requirements when the HELP system is activated.

Discussion

We view the HELP system as an auxiliary vehicular hazard warning signal flasher that is separate from the required vehicular hazard warning signal flasher, and which is activated under certain limited conditions.  Because it is not required equipment, the primary restriction that FMVSS No. 108 imposes on the HELP system is that the system may not impair the effectiveness of the vehicle’s required lighting equipment.[2] 

As discussed below, we have determined that there are two aspects of the HELP system that could potentially impair the effectiveness of a vehicle’s required lighting equipment. The first relates to the manner in which the driver manually activates the system using the hazard button. The second relates to the actual operation of the HELP system once it is activated.   

System Activation

FMVSS No. 108 requires that a vehicle’s hazard warning system be operated by a switch (or set of switches) that can be actuated with a single action by the driver.[3]  Although this requirement is technically met by the manual switch described in your supplemental submission, since the hazard warning system could be activated with one action both when the HELP system is activated and when it is not activated, we believe that the method of activation you describe would impair the effectiveness of the hazard warning system, as it would confuse a driver who is not familiar with the HELP system.  Since most vehicles are designed in a way that a second press of the hazard button deactivates the hazard warning system, it is reasonable to foresee a scenario in which a driver of a vehicle equipped with the HELP system presses the hazard button intending to turn both systems off, and not realizing that doing so would require two additional presses. 

Given the risk of accidental activation of both the HELP system and the required hazard warning system due to confusion over the activation of the two systems using a single button, we have concluded that incorporating manual activation of the HELP system into the hazard button would impair the effectiveness of lighting equipment required under FMVSS No. 108.

System Operation

In an interpretation letter analyzing impairment under FMVSS No. 108, NHTSA explained that there are, in essence, four ways that a lamp could impair effectiveness: brightness, color, location, and activation pattern.[4]  Since the HELP system operates through the use of the vehicle’s existing required turn signal lamps, and does not purport to alter the brightness, color, or location of those lamps, we do not believe use of the HELP system would impair the effectiveness of the vehicle’s lighting system on the basis of brightness, color, or location. 

However, there are concerns regarding the fourth criterion: the activation pattern of the turn signal lamps.  When a required turn signal lamp is activated using either the required turn signal flasher or the required vehicular hazard warning signal flasher, the vehicle’s turn signal lamps must flash at a rate of 1-2 hertz.[5]­­,[6] ­ ­­­­However, when the turn signal lamps are activated using the HELP system, they would flash at a rate that could be as much as three times higher (2-6 hertz).  Ultimately, the question of whether the HELP system is permitted under FMVSS No. 108 depends on whether this higher flash rate would impair the effectiveness of the vehicle’s required lighting equipment.

We have considered this impairment issue by analyzing the HELP system as it would be used in two separate circumstances.   

First is its capability of automatically activating following a serious crash.  FMVSS No. 108 requires that a hazard warning operating unit be “driver controlled.”  However, as NHTSA explained in letters to Mr. Timothy Bartlett[7] and Mr. Brian Latouf,[8] automatic activation of the hazard warning system is permitted in certain, limited situations in which there was no ambiguity regarding the reason for the hazard system’s activation.  In the Bartlett letter, we stated the hazard warning system could activate automatically following a crash.  In the Latouf letter, we said the hazard warning signals could activate when a vehicle operated using GM’s “Super Cruise” partial automation system comes to a stop after finding the driver unresponsive.  In both situations, the purpose for which the hazard warning system is being used—to warn other road users of the disabled or stopped vehicle—is unambiguous.  

Applying this reasoning to your system, we likewise conclude that the HELP system would not impair a vehicle’s required lighting equipment when limited to automatic activation following a crash that disables the vehicle, such as one in which the air bags are triggered.  As you indicated in your request, the purpose of the HELP system’s 2-6 hertz flash rate is to increase conspicuity of a vehicle in an emergency.  We believe the risk of impairment is low if activated when the vehicle is disabled following a crash, since the crash would almost certainly create an emergency in which conspicuity of the vehicle’s lamps is of primary importance.[9] 

The second circumstance involves the manual activation of the HELP system.  While the HELP system is an auxiliary system that is not subject to the requirements that apply to the hazard warning system, NHTSA has the same concern about the ambiguity of the meaning of the HELP system’s operation that it expressed in the letters to Mr. Bartlett and Mr. Latouf.  Unlike an automatic activation when the vehicle is disabled following a crash, if the system can be manually activated, NHTSA is concerned that the HELP system could be activated in a wide array of non-emergency situations that could confuse other road users.  Given that there is a higher risk of impairment if the vehicle allows manual activation of the HELP system, we have concluded that if it is possible to activate the system manually, your system is permissible under the impairment prohibition only if its activation is restricted to when the vehicle is not moving and either the vehicle is in park or the parking brake is engaged.  Moreover, consistent with our determination in the previous section, the switch that activates the HELP system must be separate from the hazard button, and must be designed so that it is not easily confused with the hazard button.  

Please note that, while this letter finds that the HELP system does not necessarily violate the prohibition on impairment, it is the responsibility of the certifying vehicle manufacturer to ensure that the particular implementation of the system in a vehicle would not impair the effectiveness of required lighting equipment.

Sincerely,

Jonathan C. Morrison

Chief Counsel

Dated: 1/19/21

Ref: FMVSS No. 108

[1] You state in your letter that the system would activated the “hazard warning lamps.”  Hazard warning lamps are not a type of lamp that NHTSA regulates.  Rather, vehicles are required to be equipped with a “Vehicular hazard warning signal flasher,” which is a device that, when activated, causes all the vehicle’s turn signal lamps to flash simultaneously.

[2] See FMVSS No. 108, S6.2

[3] See FMVSS No. 108, S9.6.2

[4] https://isearch.nhtsa.gov/files/571.108%20--%20AMA%20--%20Schaye--front%20color%20changing%20light.htm

[5] See FMVSS No. 108, S14.9.3.5.3, S14.9.3.9.3, and Figure 2

[6] Although you were correct when you stated in your supplemental submission that this flash rate was chosen in large part due to the limitations of incandescent light sources that existed at the time the standard was adopted, the maximum flash rate is specified in Standard 108, and cannot be changed except through the rulemaking process.

[7] https://isearch.nhtsa.gov/files/23695.ztv.html

[8] https://isearch.nhtsa.gov/files/16-1289%20(GM%20hazard%20innovative)%20--%2028%20Apr%2016%20rsy.htm

[9] To be clear, NHTSA is unable to agree with your assertions that the HELP system would provide the safety benefits you describe in your request and supplemental submission. Our letter today does not endorse or concur with such statements.