Federal Motor Vehicle Safety Standards; Pedestrian Head Protection, Global Technical Regulation No. 9; Incorporation by Reference

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Summary

A. This Proposed Standard

B. Potential Impacts of the Rulemaking

II. Safety Need

III. Foundations of the Proposal

IV. The Global Technical Regulation

A. Introduction

B. GTR 9

C. Further Observations About the Differences Between This NPRM and the GTR

V. Approach of the Proposed Standard

A. Overview

B. Relevance to the Involved Vehicles

C. Advantages of Headform Component Tests

D. Head Injury Criterion (HIC)

E. Speed and Angle at Which the Headforms Would Impact the Hood

VI. Defining the Relevant Areas Subject to the Standard

A. Determining the Hood Top

B. Hood Area

C. Defining the Child Headform Test Area and the Adult Headform Test Area

VII. Proposed Requirements and Assessing Compliance

A. Amount of Hood Area That Must Conform to HIC 1000

B. Manufacturer Designations of HIC1700 Areas

C. First Point of Contact

D. Consideration Related to the Amount of Test Area That Must Meet the HIC100 and HIC1700 Limits

E. Considerations for Expansion of Test Area When It Is Less Than Two Thirds of the Numerical Value of the Hood Area

VIII. GTR 9 Terminology and Amendment 3

A. Comparison of Terminology

B. Amendment 3

IX. Headform Characteristics

A. General

B. Qualification Limits

C. Repeatability and Reproducibility

X. Other Issues

A. Active Hoods

XI. Effect on Other Standards

XII. Proposed Lead Time

XIII. Benefits and Costs

XIV. Considered Alternatives

XV. Rulemaking Analyses and Notices

XVI. Public Participation

I. Executive Summary

Improving pedestrian safety is a high priority of the Department of Transportation. Data show pedestrian fatalities increasing substantially in recent years. NHTSA issues this NPRM in an effort to address this safety problem. This NPRM proposes a new Federal Motor Vehicle Safety Standard (FMVSS) that would ensure that passenger vehicles are designed to reduce the risk of serious to fatal child and adult head injury in pedestrian crashes. This rulemaking initiates the process of adopting a Global Technical Regulation (GTR) on pedestrian protection as an FMVSS, with focused enhancements to the GTR to address safety problems and a regulatory framework unique to the U.S. In addition, this NPRM furthers the goals and policies of DOT's January 2022 National Roadway Safety Strategy, which describes the five key objectives of the Department's Safe System Approach: safer people, safer roads, safer vehicles, safer speeds, and post-crash care.

New Federal Motor Vehicle Safety Standard No. 228, Pedestrian head protection, would apply to passenger cars, light trucks (including pickups), multipurpose passenger vehicles (MPVs) (MPVs include sport utility vehicles (SUVs), crossover vehicles and vans) and buses with a GVWR of 4,536 kg (10,000 lb) or less. The standard would require vehicles to meet a head injury criterion (HIC) when subjected to testing simulating a head-to-hood impact. The vehicles would have to reduce the risk of serious to fatal head injury to child and adult pedestrians in impacts at vehicle speeds up to 40 km/h (25 mph), which encompass about 70 percent of pedestrian injuries from vehicle impacts. Moreover, it is expected the standard would be beneficial even at higher speeds. This NPRM advances NHTSA's objective of adopting a motor vehicle crashworthiness safety standard to ensure that passenger vehicles are designed to mitigate the risk of serious to fatal child and adult pedestrian head injury.

This NPRM is part of a multi-step approach to enhance vehicle performance against pedestrian injury. First, it initiates the process of adopting Global Technical Regulation No. 9 (GTR 9), “Pedestrian safety,” into the Federal safety standards. NHTSA has collaborated with governments internationally to develop GTR 9, and numerous countries have adopted the GTR into their regulations. FMVSS No. 228 would establish a pedestrian standard domestically, to ensure that all vehicles with a GVWR of 4,536 kg (10,000 lb.) or less manufactured in or imported into the United States—including a sub-group of light trucks (large pickups and large SUVs) more common in the U.S. than in other parts of the world—mitigate the risk of serious head injury to pedestrians.

Second, the standard would provide a regulatory counterpart to NHTSA's planned crashworthiness pedestrian protection testing program in the New Car Assessment Program (NCAP) in the near term. On May 26, 2023, NHTSA published an NCAP Request for Comment (NCAP RFC) proposing to adopt a crashworthiness pedestrian protection program into NHTSA's NCAP. NCAP would build on proposed FMVSS No. 228 and incorporate enhanced crashworthiness tests into NCAP that go beyond the specifications of proposed FMVSS No. 228. NCAP remains a consumer information program that provides consumers with vehicle safety information for their purchasing decisions. Providing this information encourages manufacturers to voluntarily make changes to vehicles that reflect positively in the NCAP safety information and thereby improves safety through the marketplace. FMVSSs, on the other hand, are mandatory and mandate at least a minimum level of safety that all new vehicles must provide to every purchaser. NHTSA has observed that, in the case of both electronic stability control and rear visibility cameras, only approximately 70 percent of vehicles had these technologies during the time they were part of NCAP. Thus, while NCAP serves a vital safety purpose, NHTSA also recognizes its limitations in ensuring that every vehicle provides the performance necessary to provide the requisite level of safety to all purchasers. Because only an FMVSS can ensure that all vehicles are equipped with technologies and vehicle designs that meet the specified performance requirements, NCAP can supplement but not substitute for the FMVSS. The FMVSS remains NHTSA's core way of ensuring that all motor vehicles provide the requisite level of safety performance, and provide it within a practicable timeframe. Although the NCAP program provides valuable safety-related information to consumers in a simple and easy-to-understand manner, the agency believes that the proposed rule is necessary to achieve the highest level of pedestrian safety feasible and at the fastest achievable timeframe based on the performance requirements and lead time specified in the proposed rule. Additional discussion on the NCAP RFC is provided later in this preamble.

Third, this rulemaking proposing FMVSS No. 228 is intended to work hand-in-hand with the growth and expansion of automatic emergency braking (AEB) technologies. An AEB system uses various sensor technologies and sub-systems that work together to detect when the vehicle is in a crash imminent situation, to automatically apply the vehicle brakes if the driver has not done so, or to apply more braking force to supplement the driver's braking. AEB systems were originally developed to detect a crash imminent situation with a lead vehicle, but AEB is in a state of rapid advancement and some of the systems on the market now also warn about, and respond to, an imminent collision with a pedestrian. Pedestrian AEB (PAEB) systems are designed to stop the vehicle automatically before striking a pedestrian or reduce the speed at which an impact occurs if the vehicle's initial speed is too high to avoid impact. On May 9, 2024, NHTSA published a final rule requiring AEB and PAEB systems on light vehicles which adopts FMVSS No. 127. FMVSS No. 127 builds on a voluntary commitment, announced by NHTSA in March 2016, by 20 vehicle manufacturers to make lead-vehicle AEB a standard feature on light vehicles, though that commitment did not include PAEB. When new vehicles are equipped with PAEB, we anticipate that fewer pedestrians will be struck. For some impacts that cannot be avoided due to the closing speed of the vehicle (the relative speed between the vehicle and what it is approaching, in this case, the pedestrian), PAEB will lower the vehicle's speed so more impacts will be at speeds of 40 km/h (25 mph) or less, which is the velocity range FMVSS No. 228 is designed to replicate. FMVSS No. 228 would address those crashes and ensure the vehicles mitigate the risk of serious to fatal head injury in these impacts. PAEB will eliminate many pedestrian impacts and reduce the impact of those crashes that do occur. This NPRM, if adopted, would further reduce the risk of serious injury or death from head injuries if a pedestrian strikes the hood of a vehicle. NHTSA has accounted for the effect of FMVSS No. 127 in estimating the economic impacts of this rulemaking.

This NPRM proposes FMVSS No. 228 and aligns with the goals of DOT's January 2022 National Roadway Safety Strategy, which describes the five key objectives of the Department's Safe System Approach: safer people, safer roads, safer vehicles, safer speeds, and post-crash care. FMVSS No. 228 would mandate requirements for safer vehicles and leverage advanced crash avoidance technology like PAEB in conjunction with the crashworthiness countermeasures based on GTR 9 to realize far-reaching improvements to pedestrian safety. NHTSA also notes that although research into vulnerable road users and vehicle safety measures has focused predominantly on improving the protection of pedestrians, several effectiveness studies have concluded that pedestrian safety measures like this NPRM's head protection requirements would also be beneficial for cyclists.

Issuance of this NPRM is also consistent with the goals of the November 15, 2021, Infrastructure Investment and Jobs Act (IIJA). Section 24211 of IIJA, “Global Harmonization,” states that the Secretary shall cooperate, to the maximum extent practicable, with foreign governments, nongovernmental stakeholder groups, the motor vehicle industry, and consumer groups with respect to global harmonization of vehicle regulations as a means for improving motor vehicle safety. This NPRM proposes to adopt an FMVSS for pedestrian head protection founded on Global Technical Regulation No. 9, “Pedestrian Safety” (GTR 9). NHTSA collaborated with experts from around the world to develop GTR 9. Establishing an FMVSS based on a Global Technical Regulation aligns with the goals of IIJA Section 24211.

Although GTR 9 was established in 2008 when light trucks and vans (LTVs), which includes large light trucks, MPVs (including SUVs) and vans, were not as common as they are now in the U.S., LTVs did exist then, and the GTR test procedure included in proposed FMVSS No. 228 was developed to be relevant and applicable to these LTV vehicles. The test procedure proposed for use in FMVSS No. 228 is relevant for use with all light vehicles in the U.S. fleet because it is based on a Wrap Around Distance (WAD) measurement appropriate for use with passenger cars and LTVs. The defined “Hood Area” (subject to proposed FMVSS No. 228 coverage) is based on WAD, so any differences in head impact locations for a given crash scenario between LTVs and passenger cars are accounted for in the WAD-based test. As described in sections V.-VII., in the proposed test, NHTSA would use impactor testing to simulate a head-to-hood or head-to-fender top impact. It would specify the use of two different impactors: one representative of the head of a struck 6-year-old child (child headform) and another representative of the head of a struck 50th percentile adult male pedestrian (adult headform). The WAD measurement assures that the areas of the hood subject to impactor testing are the areas likely to be struck by a pedestrian's head. NHTSA has performed the WAD-based test of GTR 9 on a wide variety of vehicles, including LTVs of various shapes and sizes. These data have been used to generate the benefit-cost analysis for this NPRM, which NHTSA discusses in the Preliminary Regulatory Impact Analysis (PRIA) accompanying this NPRM. The PRIA, discussed in detail in sections below, calculates benefits and costs separately for passenger cars and LTVs.

Because the WAD-based test procedure of the GTR is technically suitable for small and large vehicles, this NPRM's regulatory text reflects the wording of GTR 9 to show the GTR's provisions implemented in a Federal motor vehicle safety standard. Throughout this preamble, however, NHTSA requests comments on the pros and cons of various aspects of the NPRM's regulatory text, particularly with respect to the areas of the vehicle that would be subject to headform testing strictly using the GTR procedure. Throughout this preamble, NHTSA focuses readers on ways NHTSA believes the proposed regulatory text could be enhanced in a final rule to achieve more safety benefits in the U.S. For example, we discuss an approach of potentially extending the test area to the grille area on all large vehicles where the head of a child or shorter adult pedestrian may be struck. With pedestrian injury and fatality rates climbing, and with lessons learned from NHTSA's NCAP and other NCAP programs engaged in headform testing of vehicle front ends, NHTSA seeks to design FMVSS No. 228 to be as effective as possible to address pedestrian safety needs in the U.S.

Accordingly, this NPRM discusses specific approaches that NHTSA is considering to possibly tailor the GTR text for a final rule. While the NPRM's regulatory text reflects the GTR's approaches and provides a framework for an FMVSS based on those provisions, NHTSA may determine to make changes in any final rule. Ultimately, NHTSA seeks to issue a final rule that would “fully meet the need in the U.S. for vehicle safety.”

A. This Proposed Standard

In collisions between vehicles and pedestrians, the pedestrian is typically struck from the side while walking across the vehicle's path. When a pedestrian is struck in this manner, the first point of contact typically occurs between the front-end of the vehicle and the lateral aspect of the pedestrian's leg near the knee region. As the lower leg becomes fully engaged with the vehicle's front-end, the leading edge of the hood strikes the lateral aspect of the pedestrian's pelvis or upper leg. Then, as the lower leg is kicked forward and away from the front-end of the vehicle, the pedestrian's upper body swings abruptly downward towards the hood until the head strikes the vehicle. Research indicates that the linear head impact velocity ranges between 60 and 110 percent of the initial contact velocity.

Proposed FMVSS No. 228 is designed to mitigate injuries to pedestrians hit from the side as described above. Most pedestrian injuries (79%) and fatalities (83%) are caused by the frontal structures of vehicles. Roughly two-thirds of these occur when vehicle travel speeds are less than 40 km/h (25 mph). Crash data show that pedestrian head injuries occur due to contacts to all areas of vehicle front ends, including the hood. The location the pedestrian's head strikes is dependent on the pedestrian's size, the front configuration of the vehicle, and the speed of impact. In a 40 km/h (25 mph) impact, roughly 15% of pedestrian fatalities involve the pedestrian's head contacting the Hood Top. This NPRM focuses on mitigating head injuries sustained from contacting the hood and adjacent areas around the hood on the vehicle front end.

Proposed FMVSS No. 228 would use impactor testing simulating a head-to- hood or head-to-fender top impact. It would specify the use of two different impactors: one with a mass of 3.5 kg that is representative of the head of a struck 6-year-old child (child headform) and another with a mass of 4.5 kg representative of the head of a struck 50th percentile adult male pedestrian (adult headform). The standard would define various areas of a test vehicle hood (such as the Hood Top and Hood Area) subject to testing in an objective and repeatable manner. The Hood Area would be partially composed of the Child Headform Test Area and the Adult Headform Test Area. The area likely to be struck by a child pedestrian's head (the Child Headform Test Area) would be tested with the child headform and the area likely to be struck by an adult's head (the Adult Headform Test Area) would be tested with the adult headform. The headforms would hit areas of the vehicle hood at specific speeds and impact angles replicating a real-world vehicle traveling at 40 km/h (25 mph) and impacting the adult or child pedestrian.

The following figure generally depicts the areas of a vehicle that would be subject to FMVSS No. 228 testing, particularly the Hood Top and Hood Area (which share a boundary in this example and are contained within the dashed lines), and the Child and Adult Headform Test Areas (darkly shaded areas). The figure illustrates other terms and concepts used in the proposed standard. All of the terms used in the figure are fully explained in this preamble.

Proposed FMVSS No. 228 would specify performance requirements limiting the accelerations measured by the headforms. The HIC must be less than 1000 (HIC1000) over a certain portion of the Child and Adult Headform Test Areas. The requisite portions would be derived as a percentage of the overall Hood Area. Generally speaking, the portion of the Child Headform Test Area that must meet the HIC1000 requirement must be at least one-half of the numerical value (numerical value of the area is calculated from a projection onto a horizontal plane) of the Hood Area below what is called the “WAD1700 line.” Based on data showing the locations of child and adult head impacts, this NPRM proposes that WAD1700 would be the boundary between the Child Headform Test Area and the Adult Headform Test Area. Secondly, the portion of the Combined Child and Adult Headform Test Areas that must comply with the HIC1000 limit must be at least two-thirds of the numerical value of the Hood Area. Because hard areas under the hood are challenging to mitigate, for practicability reasons the HIC limit for the remaining test areas is higher, but nonetheless limited to HIC1700.

To meet the HIC limits, hoods would be required to have protective countermeasures that attenuate the energy of the impact during initial contact of the headform, and/or that provide sufficient clearance (open areas) to prevent the headform from bottoming out on objects beneath the hood. The countermeasures would have to ensure that the hood is not too stiff (such a hood would fail the HIC requirement) and not too soft (a too soft hood could also fail because the headform could penetrate down to the level of a hard, immovable structure beneath the hood). Among other objectives, an effective design balances hood stiffness with depth of penetration.

B. Potential Impacts of the Rulemaking

FMVSS No. 228 would apply to passenger cars and to MPVs, trucks, and buses with a GVWR of 4,536 kg (10,000 lb) or less. Due to the widespread adoption and use of GTR 9 by other countries, most passenger vehicles sold in the U.S. that use international platforms already incorporate the head protection designs of the GTR. Regardless of current voluntary conformance, we propose to adopt GTR 9 into an FMVSS to ensure future vehicles provide at least the pedestrian head protections voluntarily provided today. We also seek to address the many U.S. variants and other models built upon uniquely American platforms that may or may not be designed to the GTR requirements. This includes essentially the entire pickup truck and large SUV segments (about 22% of the U.S. passenger vehicle 2020 sales, according to data provided by Wards Automotive). Our testing indicates that it is possible for some pickup trucks to pass the headform HIC requirements, which implies domestic implementation is feasible. This proposal would ensure that uniquely American platforms, such as pickups, would provide the proposed level of pedestrian head protection. In this NPRM, NHTSA also considers modifying some aspects of GTR 9 to clarify the wording of the regulation, improve objectivity, and potentially increase safety benefits resulting from the GTR's application to the U.S. fleet. NHTSA proposes a domestic FMVSS No. 228 to achieve those enhancements.

This NPRM is economically significant under Executive Order 12866 due to the benefits estimated to result from the proposed standard. NHTSA's PRIA analyzes the potential impacts of proposed FMVSS No. 228. NHTSA has placed a copy of the PRIA in the docket for this NPRM.

NHTSA estimates that the proposal would mitigate approximately 67.4 fatalities annually, even after accounting for the effect of PAEB. (However, as explained in detail in sections below, the count of injuries will increase as averted fatalities are replaced by injuries.) For passenger cars, the cost per vehicle is estimated to be in the range of $2.86-$3.50 when discounted at 3% and 7%. Similarly, LTVs have a per vehicle cost of $3.29-$4.08. When discounted at 3% and 7%, the total annual cost ranges from $48.94 to $60.43 million. The overall discounted equivalent lives saved (ELS) range from approximately 44.46 to 54.87. Taking into account both discount rates, the cost per ELS is $1.10 million and net benefits range from approximately $480.79 to $593.33 million. Table I.1 summarizes the cost and benefits for both discount rates. Additional details of the benefits and costs analysis can be found in section X.III of this preamble.