Interpretation ID: NCC-230308-001 NelsonMullinsParkingBrakeIndicatorInterp

October 31, 2024

Ms. Christie L. Iannetta
Nelson Mullins Riley & Scarborough LLP
101 Constitution Ave, NW, Suite 900
Washington, DC 20001

Dear Ms. Iannetta:

This interpretation responds to your letter regarding Federal Motor Vehicle Safety Standard (FMVSS) No. 135, Light vehicle brake systems. Specifically, you asked about paragraph S5.5.1 of FMVSS No. 135, which outlines the requirements for when certain brake indicators must be activated. Your question focuses on subparagraph (c), which requires that an indicator be activated when there is “[a]pplication of the parking brake.” You asked the agency to confirm that “a parking brake visual indicator that illuminates when a driver intentionally activates the electronic parking brake via the park brake control meets the requirements of FMVSS No. 135, S5.5.1(c), but that when the same electronic parking brake is automatically applied by the vehicle, the parking brake visual indicator may, but is not required, to illuminate to be considered compliant with this same provision.” Based on the information you have provided, our answer is that this requested confirmation does not provide an accurate understanding of FMVSS No. 135. To comply with FMVSS No. 135, a parking brake indicator must be activated whenever a parking brake is engaged, regardless of how the parking brake is applied.

Background
By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under 49 U.S.C. Chapter 301, manufacturers are required to ensure that their vehicles and equipment meet applicable requirements.

Please also note that our answer below is based on our understanding of the specific information provided in your letter. This interpretation letter does not have the force and effect of law and is not meant to bind the public in any way. This letter is intended only to provide clarity regarding existing requirements under the law and represents the opinion of the agency on the questions addressed in your letter at the time of signature.

FMVSS No. 135
FMVSS No. 135 establishes requirements for light vehicle braking systems. Paragraph S5.5.1 of FMVSS No. 135 requires indicators to be activated when the ignition (start) switch is in the “on” (“run”) position and one or more of seven scenarios occur. Paragraph (c) of S5.5.1 requires an indicator to be activated upon “application of the parking brake.” So if the parking brake is applied and the vehicle’s ignition is in the “on” position, a parking brake indicator must be activated.

Your Question and NHTSA’s Response
In your letter, you describe a manufacturer’s Electronic Parking Brake (EPB) system. You indicate the EPB system is integrated into the rear foundation brake calipers and is not separately serviceable. Your letter states that the EPB can be applied manually by the driver or automatically by the system. When the driver manually applies the parking brake control, upon successful confirmation of engagement of the EPB, a visual indicator appears on the user interface in plain view of the driver. You state that the EPB visual indicator remains illuminated while the EPB is engaged as a reminder to the driver to manually release the parking brake before driving.

In addition to the manual application of the parking brake, your letter indicates that there are scenarios when the EPB automatically engages, even when the driver does not manually activate the EPB, including when the vehicle is shifted into park. You explain that if a driver puts the vehicle in park and does not manually apply the parking brake, the vehicle will automatically apply the EPB. If the vehicle automatically applies the EPB, the parking brake indicator is not activated. Lastly, you indicate that when the driver shifts out of park, the EPB system is automatically deactivated.

In your letter, you assert the manufacturer’s view that this system is compliant with FMVSS No. 135 S5.5.1(c) because the regulation requires display of the parking brake only when the driver manually applies the parking brake. You point to previous interpretations that NHTSA has published, where we explain that the parking brake indicator requirement was promulgated to ensure drivers do not drive with the parking brake engaged. You assert that because the manufacturer’s EPB system eliminates this risk, the system should be considered compliant. Additionally, you assert that the regulatory history and language of the standard point to this system being compliant under paragraph S5.5.1.

After careful consideration of both the standard and the arguments made in your letter, the agency has concluded that the EPB system described in your letter would be considered noncompliant with FMVSS No. 135 S5.5.1(c). As discussed above, FMVSS No. 135 S5.5.1(c) requires that if a vehicle ignition is switched to the “on” position and the parking brake is applied, an indicator must activate to inform the driver of the status of the parking brake. From the details in your letter, there would be scenarios where the vehicle you described would have the ignition switched to the “on” position with the parking brake applied, but the parking brake indicator would not be activated. To use the example from your letter, if a driver puts the vehicle in the park position and does not activate the parking brake manually, the parking brake will automatically apply, but no parking brake indicator will be active. The system you describe in
your letter would be considered noncompliant under FMVSS No. 135 S5.5.1(c). Simply put, if the parking brake is applied, the parking brake indicator must be activated.

Your letter asserts that the phrase “application of the parking brake” in paragraph S5.5.1(c) refers to an action that the driver takes via the “parking brake control.” You state that a driver cannot “apply” a parking brake system, but only the control, meaning that the parking brake indicator requirement only applies when the driver manually applies the parking brake. We disagree with this reading, which is inconsistent with both the language and the intent of the standard. Had S5.5.1(c) been intended to cover only manual application of the parking brake control, it would say so. Other parts of FMVSS No. 135 refer to application and activation of the “parking brake control”1; by contrast, S5.5.1(c) refers more generally to the “parking brake.” Moreover, FMVSS No. 135 makes multiple references to manual application, actions, or controls, without doing so in S5.5.1(c).2

As you state in your letter, when FMVSS No. 135 was first promulgated, manual application of the parking brake was the only way a parking brake could be engaged. However, FMVSS No. 135 has been updated multiple times since it was first issued in 1995, including as recently as 2022,3 and it has never been amended to specify that S5.5.1(c) applies only to manual application of the “parking brake control.” This history, and the lack of a manual application requirement or reference to the parking brake control in S5.5.1(c), show the agency intended the parking brake indicator to be active whenever the parking brake is engaged, regardless of how the brake is engaged.

Moreover, if S5.5.1(c) covered only manual application of the parking brake control, then no indicator would be required when a vehicle automatically engages the parking brake, even if nothing prevents the vehicle from driving during this engagement—a circumstance when an indicator would be especially essential because the driver may not have consciously activated the parking brake. In fact, your letter’s description of the manufacturer’s EPB system suggests there may be circumstances where the parking brake in the manufacturer’s vehicle is automatically engaged other than when the driver shifts the vehicle to “Park.”

The distinction your letter makes between a vehicle’s “parking brake” and its “parking brake system” does not change this analysis. “Parking brake system” has no regulatory definition.4 “Parking brake,” which is the term used in S5.5.1(c), is defined as “a mechanism designed to prevent the movement of a stationary motor vehicle.”5 The definition does not distinguish between mechanisms that are activated by a designated manual control and mechanisms that are activated by other means. S5.5.1(c) simply requires activation of the indicator when the parking brake mechanism is engaged.

The agency has also considered the arguments you made in your letter regarding previous interpretations NHTSA has published on the parking brake indicator requirement. NHTSA has indicated in interpretations that the purpose of the parking brake indicator requirement is to prevent drivers from driving their vehicles with the parking brake activated. Doing so could potentially lead to excessive wear on the transmission and parking brake system, which could cause a variety of safety issues.6 However, just because a manufacturer has designed a system that purports to resolve, though other means, a safety concern addressed in an FMVSS does not mean that it is not bound by the requirements of the FMVSS or that it may introduce noncompliant motor vehicles or motor vehicle equipment to the market. If a manufacturer believes that it has developed technology that makes certain regulatory requirements unnecessary, it may petition the agency for a rulemaking to amend the relevant requirements. It may also request an exemption from an applicable standard if it has reason to believe it is eligible.7 Otherwise, the current requirements apply.

Accordingly, the plain meaning and intent of S5.5.1(c) is for the parking brake indicator to be active any time the parking brake is engaged and the vehicle’s ignition is in the “on” position. This requirement applies regardless of whether the parking brake is engaged through the manual application of the designated parking brake control or through other means.

I hope this letter answers all of your questions. If you have any further questions regarding this matter, please feel free to contact Mr. Matthew Filpi of my staff at (202) 366-2992.

Sincerely,
ADAM RAVIV
Adam Raviv Chief Counsel
 

Dated: 10/31/24
Ref: Standard No. 135

1 See FMVSS 135 S.7.12.2(b), (i), (l).
2 See FMVSS 135 S5.3.2, S6.3.5, S6.3.11.2.
3 See 87 FR 34810 (Jun. 8, 2022).
4 The only published definition your letter provides for “parking brake system” is a proposed definition, never implemented, in FMVSS No. 121, which is a separate standard for air brake systems in trucks, buses, and trailers. Your letter also argues that “[t]he driver cannot ‘apply’ the parking brake system, only the control (e.g., using a lever or button).” In fact, FMVSS No. 135 indicates otherwise: it discusses how to test the parking brake “[i]n the case of a parking brake system that does not allow application of the specified force in a single application.” S7.12.2(j).
5 49 C.F.R. § 3(b).
6 See Letter to Headley, May 30, 2002, available at https://www.nhtsa.gov/interpretations/23871jeg#:~:text=We%20noted%20that%20the%20purpose%20of%20the,wa s%20applied%20(and%20hence%20should%20be%20released; see also Letter to Selander, Apr. 29, 2002, available at https://www.nhtsa.gov/interpretations/6992.
7 See, e.g., 49 C.F.R. § 556.