New Car Assessment Program (NCAP) |
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Mark R. Rosekind
National Highway Traffic Safety Administration
November 5, 2015
[Federal Register Volume 80, Number 214 (Thursday, November 5, 2015)]
[Notices]
[Pages 68604-68618]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-28052]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
[Docket No. NHTSA-2015-0006]
New Car Assessment Program (NCAP)
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation (DOT).
ACTION: Final decision.
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SUMMARY: On January 28, 2015, NHTSA published a notice requesting
comments on the agency's intention to recommend various vehicle models
that are equipped with automatic emergency braking (AEB) systems that
meet the agency's performance criteria to consumers through the
agency's New Car Assessment Program (NCAP) and its Web site,
www.safercar.gov. These systems can enhance the driver's ability to
avoid or mitigate rear-end crashes. This notice announces NHTSA's
decision to include AEB technologies as part of NCAP Recommended
Advanced Technology Features, if the technologies meet NCAP performance
criteria. The specific technologies included are crash imminent braking
(CIB) and dynamic brake support (DBS).
DATES: These changes to the New Car Assessment Program are effective
for the 2018 Model Year vehicles.
FOR FURTHER INFORMATION CONTACT: For technical issues: Dr. Abigail
Morgan, Office of Crash Avoidance Standards, Telephone: 202-366-1810,
Facsimile: 202-366-5930, NVS-122. For NCAP issues: Mr. Clarke Harper,
Office of Crash Avoidance Standards, email: Clarke.Harper@DOT.GOV,
Telephone: 202-366-1810, Facsimile: 202-366-5930, NVS-120.
The mailing address for these officials is as follows: National
Highway Traffic Safety Administration, 1200 New Jersey Avenue SE.,
Washington, DC 20590.
SUPPLEMENTARY INFORMATION:
I. Executive Summary
II. Background
III. Summary of Request for Comments
IV. Response to Comments and Agency Decision
A. Harmonization
B. Rating System for Crash Avoidance Technologies in NCAP
C. Draft Test Procedures
D. Proposed Additions to Test Procedures
E. Proposed Additions to Test Procedures
F. Other Issues
V. Conclusion
I. Executive Summary
This notice announces the agency's decision to update the U.S. New
Car Assessment Program (NCAP) to include a recommendation to motor
vehicle consumers on vehicle models that have automatic emergency
braking (AEB) systems that can substantially enhance the driver's
ability to avoid rear-end crashes. NCAP recommends crash avoidance
technologies, in addition to providing crashworthiness, rollover, and
overall star ratings. Today, 3 crash avoidance technologies--forward
collision warning, lane departure warning, and rearview video systems--
are recommended by the agency if they meet NHTSA's performance
specifications.
NHTSA is adding AEB as a recommended technology, which means that
we now have tests for AEB. AEB refers to either crash imminent braking
(CIB), dynamic brake support (DBS), or both on the same vehicle. CIB
automatically applies vehicle brakes if the vehicle sensing system
anticipates a potential rear impact with the vehicle in front of it.
DBS applies more brake power if the sensing system determines that the
driver has applied the brakes prior to a rear-end crash but estimates
that the amount of braking is not sufficient to avoid the crash. NHTSA
is also removing rearview video systems (RVS) as a recommended
technology in Model Year 2019, because RVS is going to be required on
all new vehicles manufactured on or after May 1, 2018, and that
technology's presence in NCAP will no longer provide comparative
information for consumers.
The vehicles that have Advanced Technologies recommended by NHTSA
may be seen on the agency Web site www.safercar.gov.
II. Background
The National Highway Traffic Safety Administration's (NHTSA) New
Car Assessment Program (NCAP) provides comparative safety rating
information on new vehicles to assist consumers with their vehicle
purchasing decisions. In addition to issuing star safety ratings based
on the crashworthiness and rollover resistance of vehicle models, the
agency also provides additional information to consumers by
recommending certain advanced crash avoidance technologies on the
agency's Web site, www.safercar.gov. For each vehicle make/model, the
Web site currently shows the vehicle's 5-star crashworthiness and
rollover resistance ratings and whether the vehicle model is equipped
with and meets NHTSA's performance criteria for any of the three
advanced crash avoidance safety technologies that the agency currently
recommends to consumers. NHTSA began recommending advanced crash
avoidance technologies to consumers
[[Page 68605]]
starting with the 2011 model year.\1\ NHTSA has under consideration
other ways of incorporating crash avoidance technologies into its NCAP
program, but those changes are not a part of this notice.
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\1\ See 73 FR 40016.
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The agency first included recommended advanced technologies as part
of the NCAP upgrade that occurred as of the 2011 model year. These
first technologies were electronic stability control (ESC), forward
collision warning (FCW), and lane departure warning (LDW).
Subsequently, in 2014, NHTSA replaced ESC, which is now mandatory for
all new light vehicles, with another technology, rearview video systems
(RVS).\2\ FCW uses forward looking sensors to detect other vehicles
ahead. If the vehicle is getting too close to another vehicle at too
high of a speed, it warns the driver of an impending crash so the
driver can brake or steer to avoid or mitigate the crash. LDW monitors
lane markings on the road and cautions a driver of unintentional lane
drift. RVS assists the driver in seeing whether there are any
obstructions, particularly a person or people, in the area immediately
behind the vehicle. RVS is typically installed in the rear of the
vehicle and connected to a video screen visible to the driver.
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\2\ On April 7, 2014, NHTSA published a final rule (79 FR 19177)
requiring rearview video systems (RVS). The rule provides a phase-in
period that begins on May 1, 2016 and ends on May 1, 2018 when all
new light vehicles will be required to be equipped with RVS. As was
done with electronic stability control, RVS will no longer be an
NCAP recommended technology after May 1, 2018, once RVS is required
on all new light vehicles.
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The agency may recommend vehicle technologies to consumers as part
of NCAP if the technology: (1) Addresses a major crash problem, (2) is
supported by information that corroborates its potential or actual
safety benefit, and (3) is able to be tested by repeatable performance
tests and procedures to ensure a certain level of performance.
Rear-end crashes constitute a significant vehicle safety problem.
In a detailed analysis of 2006-2008 crash data,\3\ NHTSA determined
that approximately 1,700,000 rear-end crashes involving passenger
vehicles occur each year.\4\ These crashes result in approximately
1,000 deaths and 700,000 injuries annually. The size of the safety
problem has remained consistent since then. In 2012, the most recent
year for which complete data are available, there were a total of
1,663,000 rear-end crashes. These rear-end crashes in 2012 resulted in
1,172 deaths and 706,000 injuries, which represent 3 percent of all
fatalities and 30 percent of all injuries from motor vehicle crashes in
2012.5 6
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\3\ These estimates were derived from NHTSA's 2006-2008 Fatality
Analysis Reporting System (FARS) data and non-fatal cases in NHTSA's
2006-2008 National Automotive Sampling System General Estimates
System (NASS/GES) data.
\4\ The 1,700,000 total cited in the two NHTSA reports reflects
only crashes in which the front of a passenger vehicle impacts the
rear of another vehicle.
\5\ See NHTSA's Traffic Safety Facts 2012, Page 70, http://www-nrd.nhtsa.dot.gov/Pubs/812032.pdf.
\6\ The approximately 1,000 deaths per year in 2006-2008 were
limited to two-vehicle crashes, as fatal crash data at the time did
not contain detailed information on crashes involving three or more
vehicles. This information was added starting with the 2010 data
year, and the 1,172 deaths in 2012 occurred in crashes involving any
number of vehicles.
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Collectively, NHTSA refers to CIB and DBS systems as automatic
emergency braking (AEB) systems. Prior to the development of AEB
systems, vehicles were equipped with forward collision warning systems,
to warn drivers of pending frontal impacts. These FCW systems sensed
vehicles in front, using radar, cameras or both. These CIB and DBS
systems can use information from an FCW system's sensors to go beyond
the warning and potentially help avoid or mitigate rear-end crashes.
CIB systems provide automatic braking when forward-looking sensors
indicate that a crash is imminent and the driver is not braking. DBS
systems provide supplemental braking when sensors determine that
driver-applied braking is insufficient to avoid an imminent crash. As
part of its rear-end crash analysis, the agency concluded that AEB
systems would have had a favorable impact on a little more than one-
half of rear-end crashes.\7\ The remaining crashes, which involved
circumstances such as high speed crashes resulting in a fatality in the
lead vehicle or one vehicle suddenly cutting in front of another
vehicle, were not crashes that current AEB systems would be able to
address.
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\7\ See ``Forward-Looking Advanced Braking Technologies Research
Report'' (June 2012). (http://www.Regulations.gov, NHTSA 2012-0057-
0001), page 12.
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The agency has conducted test track research to better understand
the performance capabilities of these systems. The agency's work is
documented in three reports, ``Forward-Looking Advanced Braking
Technologies Research Report'' (June 2012) \8\ ``Automatic Emergency
Braking System Research Report'' (August 2014) \9\ and ``NHTSA's 2014
Automatic Emergency Braking (AEB) Test Track Evaluations'' (May
2015).\10\
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\8\ See http://www.Regulations.gov, NHTSA 2012-0057-0001.
\9\ See http://www.Regulations.gov, NHTSA 2012-0057-0037.
\10\ DOT HS 812 166.
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AEB technologies were among the topics included in an April 5, 2013
request for comments notice on a variety of potential areas for
improvement of NCAP.\11\ All of those commenting on the subject
supported including CIB and DBS in NCAP. None of those submitting
comments in response to the request for comments opposed adding CIB and
DBS to NCAP. Some commenters stated generally that available research
supports the agency's conclusion that these technologies are effective
at reducing rear-end crashes, with some of those commenters citing
relevant research they had conducted. No one was specifically opposed
to including CIB and DBS in NCAP.
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\11\ See http://www.Regulations.gov, NHTSA 2012-0180.
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The agency found that CIB and DBS systems are commercially
available on a number of different production vehicles and these
systems can be tested successfully to defined performance measures.
NHTSA has developed performance measures that address real-world
situations to ensure that CIB and DBS systems address the rear-end
crash safety. The agency believes that systems meeting these
performance measures have the potential to help reduce the number of
rear-end crashes as well as deaths and injuries that result from these
crashes. Therefore, the agency is including CIB and DBS systems in NCAP
as recommended crash avoidance technologies on www.safercar.gov.
III. Summary of Request for Comments
The January 28, 2015 request for comments notice that preceded this
document sought public comment in the following four areas.
Draft test procedures:
General response to the draft test procedures;
Whether or not the draft test procedures' combination of
test scenarios and test speeds provide an accurate representation of
real-world CIB and DBS system performance;
Whether or not any of the scenarios in the draft test
procedures can be removed while still ensuring that the procedures
still reflect an appropriate level of system performance--if so, which
scenarios and why they can be removed;
Whether or not the number of test trials per scenario can
be reduced--if so, why and how; and
How the draft test procedures can be improved--if so,
which specific improvements are needed.
The strikeable surrogate vehicle (SSV) designed by NHTSA and
planned for use in CIB and DBS testing:
[[Page 68606]]
Whether or not there are specific elements of the SSV that
would make it inappropriate for use in the agency's CIB and DBS
performance evaluations--if so, what those elements are and why they
represent a problem; and
Whether or not the SSV will meet the needs for CIB and DBS
evaluation for the foreseeable future--if not, why not, and what
alternatives should be considered and why.
The planned DBS brake application strategy:
Whether the two brake application methods defined in the
DBS test procedure, those based on displacement or hybrid control,
provide NHTSA with enough flexibility to accurately assess the
performance of all DBS systems; and
What specific refinements, if any, are needed to either
application method?
CIB and DBS research:
The agency wanted to know whether there is any recent
research concerning CIB and DBS systems that is not reflected in the
agency's research to date and, if so, what is that research
Twenty-one comments were received.\12\ Most of the comments were
from the automobile industry--vehicle manufacturers, associations of
vehicle manufacturers, suppliers, and associations of suppliers. In
addition, comments were received from another Federal government
entity, an organization of insurance companies, and an association of
motorcycle interests. Those in support included Advocates, Alliance,
AGA, ASC, Bosch, CU, Continental, DENSO, Ford, Infineon, IIHS, Malik,
MBUSA, MEMA, NADA, NTSB, Tesla, and TRW. Advocates supported using NCAP
to encourage vehicle safety technologies, but indicated its preference
for requiring AEB systems on new vehicles by regulation. Honda
expressed its support for NCAP generally, but did not specifically
support the addition of AEB systems to NCAP. Honda stated that it would
like these systems to be rated. IIHS said that its research on the
effectiveness of Volvo's City Safety system and Subaru's Eyesight
system indicates that NHTSA may have ``vastly underestimated the
benefit of AEB.'' Bosch said a 2009 study it conducted indicated DBS
``may be effective'' in reducing injury-related rear-end crashes by 58
percent and CIB by 74 percent.
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\12\ See http://www.Regulations.gov, NHTSA-2015-0006 for
complete copies of comments submitted. Those submitting comments
were: Advocates for Highway and Auto Safety (Advocates), Alliance of
Automobile Manufacturers (Alliance), American Honda Motor Co., Inc.
(Honda), American Motorcyclist Association (AMA), Association of
Global Automakers, Inc. (AGA), Automotive Safety Council, Inc.
(ASC), Consumers Union (CU), Continental Automotive Systems, Inc.
(Continental), DENSO International America, Inc. (DENSO), Ford Motor
Company (Ford), Infineon Technologies (Infineon), Insurance
Institute for Highway Safety (IIHS), Malik Engineering Corp.
(Malik), Mercedes-Benz USA, LLC (MBUSA), Motor and Equipment
Manufacturers Association (MEMA), National Automobile Dealers
Association (NADA), National Transportation Safety Board (NTSB),
Robert Bosch, LLC (Bosch), Subaru of America (Subaru), Tesla, and
TRW Automotive (TRW).
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The ASC, Bosch, IIHS, MEMA, and, TRW addressed the desirability of
NHTSA harmonizing its AEB NCAP test procedures and other evaluation
criteria with other consumer information/rating programs, particularly
Euro NCAP. Other commenters urged harmonization with Euro NCAP with
respect to specific details.
Many commenters (Alliance, AGA, ASC, Continental, Ford, Honda,
IIHS, MEMA) stated that they would like NHTSA to harmonize the SSV used
in NCAP with the target vehicle used in Euro NCAP Advanced Emergency
Braking System (AEBS) tests. Commenters also asked for harmonization
with specific technical areas such as brake application magnitude and
rate, brake burnishing and test speeds.
NHTSA plans to establish minimum performance criteria in the two
test procedures for CIB and DBS to be recommended to consumers in NCAP.
Comments on these test procedures were broad and very detailed.
Advocates suggested stronger criteria. Manufacturers suggested changes
to various parts of the test procedures.
Several commenters argued against the introduction of another SSV
to the vehicle testing landscape and urged NHTSA to adopt a preexisting
SSV instead to avoid imposing added vehicle testing costs on the
vehicle manufacturing industry. Specifically, AGA, ASC, Continental,
Ford, Honda, IIHS, and Tesla asked NHTSA to specify the Allgemeiner
Deutscher Automobil-Club e.V. (ADAC) target vehicle that is used by
Euro NCAP and IIHS. Bosch supported harmonization of surrogate test
vehicles generally.
The Alliance asked for further development of the SSV equipment and
tow frame structure to eliminate the use of the lateral restraint
track. The association asked that NHTSA harmonize the SSV propulsion
system with that of the ADAC propulsion system used by Euro NCAP.
The Alliance said that since the new SSV is not readily available,
its members have not been able to conduct a full set of tests to assess
the repeatability and reproducibility of the SSV relative to the ADAC
barrier or other commercially available test targets.
The Alliance requested additional clarification about the SSV
initial test set-up to maintain the intended accuracy and repeatability
of tests. Members of the Alliance also requested clarification
regarding the definition of the target ``Zero Position'' coupled with
the use of deformable foam at the rear bumper. Other SSV concerns
raised by AGA were that the energy absorption of the SSV should be
increased to minimize potential damage to the subject vehicle in the
event of an impact, that the color of the lateral restraint track used
in conjunction with the SSV be changed to avoid its being interpreted
as being a lane marking by camera-based classification of lanes, that
the possibility that the SSV could be biased toward radar systems, and
how the SSV may appear to camera systems in various lighting
conditions.
Some of the comments went beyond the changes discussed in the
January 2015 notice. The AMA said that all AEB systems included in NCAP
should be able to detect and register a motorcycle. If not, vehicle
operators may become dependent on these new technologies and cause a
crash, because the system did not detect and identify a smaller
vehicle. Advocates, AGA, Bosch, CU, Continental, Honda, IIHS, MEMA, and
NTSB said they would like a rating system for advanced crash avoidance
technologies, including CIB and DBS, which reflects systems'
effectiveness. Honda urged NHTSA to include pedestrian and head-on
crashes among the types of crashes that are covered by NCAP evaluation
of AEB systems in the future.
IV. Response to Comments and Agency Decisions
The majority of comments received were from the automobile
industry. No commenter opposed including AEB systems in NCAP.
By including CIB and DBS systems in NCAP as Recommended Advanced
Technologies, we will be providing consumers with information
concerning advanced safety systems on new vehicles offered for sale in
the United States. The vehicle models that meet the NCAP performance
tests offer effective countermeasures to assist the driver in avoiding
or mitigating rear-end crashes. In addition, the agency believes
recognizing CIB and DBS systems that meet NCAP's performance measures
will encourage consumers to purchase vehicles that are equipped with
these systems and manufacturers will have an incentive to offer more
vehicles with these systems.
[[Page 68607]]
Comments focused on the details of how the inclusion of AEB systems
into NCAP should be administered. The agency's responses to the
comments received are below.
A. Harmonization
The Alliance, AGA, ASC, Continental, Ford, Honda, IIHS, and MEMA
stated that they would like NHTSA to harmonize the SSV used in NCAP
with the target vehicle used in Euro NCAP. Some commenters requested
that NHTSA use the Euro NCAP towing system. They also wanted similar
performance criteria, such as identical test scenarios, identical
speeds, and identical tolerances.
NHTSA has carefully examined Euro NCAP specification and procedures
for AEB technologies. The agency has decided against redirecting the
program toward harmonization for several reasons, as discussed in more
detail below.
For AEB systems and their application to the U.S. market, NHTSA's
benefit estimation and test track performance evaluations began five
years ago. This work is documented in three reports, ``Forward-Looking
Advanced Braking Technologies Research Report'' (June 2012),
``Automatic Emergency Braking System Research Report'' (August 2014),
and ``NHTSA's 2014 Automatic Emergency Braking (AEB) Test Track
Evaluations'' (May 2015) with accompanying draft CIB and DBS test
procedures.
Early into its test track AEB evaluations, NHTSA staff members met
with representatives of Euro NCAP. Among the matters discussed at that
time was the need for a realistic-appearing, robust test target that
accurately emulated an actual vehicle. Specific attributes included a
need to (1) be ``realistic'' (i.e., be interpreted the same as an
actual vehicle) to systems using radar, lidar, cameras, and/or infrared
sensors to assess the potential threat of a rear-end crash; (2) be
robust (able to withstand repeated impacts with little to no change in
shape over time); (3) not impose harm to the test driver(s) or damage
to the test vehicle under evaluation; and (4) be capable of being
accurately and repeatably constructed.
Euro NCAP, as of 2014, included AEB systems in the technologies it
rates in its ``Safety Assist'' assessments. The ratings for ``Safety
Assist'' systems are in turn combined with ratings for adult occupant
protection, child occupant protection, and pedestrian protection to
determine a vehicle's overall rating. Euro NCAP assessments of AEB
systems adopted the use of a target vehicle developed by ADAC. Known as
the Euro NCAP Vehicle Target (EVT), this target is comprised of an
inflatable and foam-based frame with PVC cover. The outside of the
cover features a rear-aspect image of an actual car and retro-
reflective film over the taillights. Internally, the EVT includes a
combination of shapes and materials selected to be provide realistic
radar return characteristics. To provide longitudinal motion, the EVT
is towed.
At the time of its initial AEB evaluations, NHTSA attempted to
evaluate the EVT device. We attempted to purchase an EVT from ADAC, but
we were ultimately unable to obtain the device and its propulsion
system. To avoid research program delays, NHTSA decided to develop and
manufacturer its own strikeable surrogate vehicle. Like the EVT, the
design goal of the NHTSA equipment was to be as safe, realistic, and
functional as possible. The NHTSA SSV and tow equipment are both
commercially available, and the drawings for the equipment are publicly
available.
NHTSA has developed a carbon fiber strikeable surrogate vehicle
(SSV) that uses original equipment taillights, reflectors, brake lights
and a simulated license plate. These features help define the SSV so
that it will be interpreted by a vehicle's AEB sensing system as being
an actual vehicle. We believe that the SSV is a target vehicle that
better mimics real vehicles than other target vehicles because its
radar signature more closely resembles that of an actual vehicle. We
will be using the SSV in the AEB validation testing to confirm that AEB
systems meet the agency's performance criteria.
Manufacturers do not need to use the SSV to generate and submit
data in support of their AEB systems that are recommended to consumers
on www.safercar.gov. However, if the vehicle cannot satisfy the minimum
performance criteria of the AEB NCAP program when tested by, the
vehicle will not be able to retain its credit for the recommendation of
AEB system by NCAP.
We will continue to look for ways in which U.S. NCAP and other
consumer vehicle safety information programs around the world,
particularly Australasian NCAP, Euro NCAP and the Insurance Institute
for Highway Safety can harmonize and complement each other. We expect
one of the benefits of the U.S. NCAP and other NCAP programs having
different test procedures will be that these programs will eventually
have data that could support how best to modify these programs
harmonize some elements of the programs while retaining other elements
that are unique and necessary to each programs.
B. Rating System for Cash Avoidance Technologies in NCAP
Advocates, AGA, Bosch, CU, Continental, Honda, IIHS, MEMA, and NTSB
said they would like a rating system for advanced technologies,
including CIB and DBS, which reflects systems' effectiveness. AGA said
CIB and DBS should each be rated separately. AGA pointed out that some
CIB and DBS systems already in the marketplace would not pass the NCAP
performance criteria, but would still provide safety benefits. AGA
stated that information regarding these safety benefits would not reach
consumers under the current pass/fail approach. AGA further noted that
Euro NCAP gives credit to vehicles for the tests they do pass.
In the January 28, 2015 request for comments, the agency sought
comment on our plans to add AEB to the list of Recommended Advanced
Technologies, a feature which appears on the agency's Web site
www.safercar.gov, but did not seek comments on whether such a rating
should appear on motor vehicles.
The agency fully recognizes that published requests for comments
provide an opportunity for the public to address not only issues
specifically raised in the request for comments, but also to express
concerns in other areas. We will consider these comments in evaluating
future changes to NCAP.
C. Draft Test Procedures \13\
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\13\ See http://www.Regulations.gov, NHTSA-2012-0057-0038 for
copies of the test procedures that were the basis of comments
received.
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1. AEB Performance Criteria Stringency
While supporting NHTSA's plan to establish minimum performance
criteria that AEB systems must meet to be recommended to consumers in
NCAP, Advocates criticized the planned AEB performance criteria as
being insufficiently stringent. The Advocates' comments focused on the
speeds at which Euro NCAP testing is conducted, including:
Speeds up to 31 mph (50 kilometers per hour (km/h)) such
that 19 percent of the possible points for Euro NCAP AEB are awarded
for performance at approach speeds above the planned NHTSA NCAP
testing.
Lead vehicle stopped scenarios are tested at subject
vehicle speeds of a range of 6 to 31 mph (10 to 50 km/h), as compared
with the planned NHTSA NCAP lead vehicle stopped test which will be
conducted at a single speed of
[[Page 68608]]
25 mph (40 km/h) and permit impact at speeds up to 15 mph (24 km/h).
The Advocates further noted that Euro NCAP is proposing to
incorporate additional, more stringent AEB tests and ratings in its
star rating system beginning in 2016. These will include:
Lead vehicle stopped scenarios at subject vehicle (SV)
speeds up to 50 mph (80 km/h).
Lead vehicle moving slower tests with a SV speed of 19 to
50 mph (30 to 80km/h) approaching a principal other vehicle (POV)
moving at 12 mph (20 km/h), for a closing speed of 7 to 38 mph (11 to
61 km/h). Advocates noted that the planned NHTSA approach would include
lead vehicle moving slower tests with SV/POV speeds of 25/10 mph (40/16
km/h) and 45/20 mph (72/32 km/h), for a maximum closing speed of 25 mph
(40 km/h).
Lead vehicle braking tests with SV/POV speeds at 31/31 mph
(50/50 km/h) with a lead vehicle deceleration of 0.2 to 0.6g (2 and 6
meters per second squared [m/s\2\]).
Conversely, the Alliance suggested we reduce the stringency of the
performance criteria by deleting the lead vehicle stopped scenarios
entirely.
The proposed NCAP test scenarios and test speeds are in part based
on crash statistics, field operational tests, and testing experience.
In developing the scenarios and test speeds for this test program we
considered work done to develop the forward collision warning
performance tests. In reviewing the information concerning crashes, we
noted that the most common rear-end pre-crash scenario is the Lead-
Vehicle-Stopped, at 16 percent of all light vehicle rear-end crashes
(975,000 crashes per year).\14\
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\14\ ``Pre-Crash Scenario Typology for Crash Avoidance
Research'', DOT HS 810 767, April 2007, Table 13.
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In evaluating the test speeds we considered the practicality of
safely performing crash avoidance testing without damaging test
vehicles and/or equipment should an impact with the test target occur
during testing. Testing vehicles at speeds over 45 mph (72 km/h) may
have safety and practicality issues. Testing at speeds over 45 mph (72
km/h), the speed used in NCAP's forward collision warning test, could
potentially cause a safety hazard to the test driver and the test
engineers. The problem arises if the vehicle being tested fails to
perform as expected. For the FCW tests, warning system failure is not a
problem because the nature of the test allows the test driver to steer
away from the principal other vehicle, without any vehicle-to-vehicle
contact. However, for the AEB tests, there can be no evasive steering.
At speeds over 45 mph (72 km/h), we believe that the test vehicles in
the AEB program might experience frontal impact of the subject vehicle
into the principal other vehicle if there is a system failure or speed
reduction that does not result in a reduction of velocity of 25 mph (40
km/h). This may be a hazard to the test drivers and to people around
the test track. Also potential front end damage at higher speeds, for
the same reasons, may have unacceptable test program delays or make
completion of the tests impractical. If front end damage to the test
vehicle occurs, the agency would have to repair the test vehicle and
recalibrate its sensing system. This might take weeks to repair and to
restart the testing.
Another upper speed limitation is the practicality of running the
tests. For example, the Lead Vehicle Decelerating test becomes
difficult. The SSV rides on a 1500-ft (457 m) monorail to constrain its
lateral position within the test lane, an attribute that helps improve
the accuracy and repeatability that the slower moving and decelerating
lead vehicle scenarios may be performed. However, this track length is
too short to safely accelerate the SSV to 45 mph (72 km/h), establish a
steady state SV-to-SSV headway (to insure consistent test input
conditions), then safely decelerate the SSV to a stop at 0.3g;
conditions like those specified in the FCW NCAP decelerating lead
vehicle test scenario. These logistic restrictions have prevented NHTSA
from evaluating the durability of the SSV when subjected to the forces
of being towed at 45 mph (72 km/h). To address these concerns, the NCAP
CIB and DBS Decelerating Lead Vehicle tests are designed to be
performed from 35 mph (56 km/h).
We believe the test vehicle speeds specified in this program, (25,
35 and 45 mph) (40, 56 and 72 km/h) represent a large percentage of
severe injuries and fatalities and represent the upper limit of the
stringency of currently available test equipment.
We are therefore retaining the test speeds in the test procedures.
2. Brake Activation in DBS Testing, Profile, Rate and Magnitude
a) Brake Input Profile Selection
The Alliance suggests that because of the differences in DBS design
and performance abilities among vehicles (i.e. brake pads and rotors,
tires, suspension, etc.), the vehicle manufacturers should be allowed
to specify the brake input. (Brake input does not apply to the CIB test
because the CIB test does not include brake input in the subject
vehicle.) Vehicle manufactures thus far have taken several approaches
to DBS system activation based on brake pedal position, force applied,
displacement, application rate time-to-collision, or a combination of
these characteristics. All of these characteristics can represent how a
driver reacts in a panic stop, versus a routine stop. The Alliance
suggests the agency should use the same characteristic used by the
vehicle manufacturer, to assure the system is activated the way the
manufacturer has intended. Conversely they indicate the agency should
not dictate a specific application style and create an unrealistic
triggering condition.
In the previous version of the DBS test procedures (August 2014),
commenters pointed out that the brake characterization process used
would typically result in decelerations that exceeded the allowable
0.3g. In order to address this concern, NHTSA evaluated a revised
characterization process that now include a series of iterative steps
designed to more accurately determine the brake application magnitudes
capable of achieving the same baseline (braking without the effect of
DBS) deceleration of 0.4g for all vehicles. This deceleration level is
very close to the deceleration realized just prior to actual rear-end
crashes, and is consistent with the application magnitude used by Euro
NCAP during its test track-based DBS evaluations. This process is
included, in great detail, in the updated version of the DBS test
procedure.
(b) Brake Application Rate
The Alliance pointed out that the brake pedal application rate of
279 mm/s maximum for DBS activation differs from Euro NCAP, where the
application rate can be specified by a manufacturer as long as it is
within a range of 200 to 400 mm/s (8 to 16 in/s). Noting that there
will always be differences in dynamic abilities between vehicles, the
Alliance said that specifying the rate to 279 mm/s increases the DBS
system's sensitivity and can lead to more false activations. The
Alliance suggested that NCAP harmonize with Euro NCAP to allow
manufacturers the option to specify a brake pedal application rate
limit beyond 279 mm/s, up to 400 mm/s.
MBUSA provided a bit more detail in its comments. MBUSA noted that
values above 360 mm/s are more representative of emergency braking
situations and will be addressed in vehicle designs using conventional
brake assist rather than AEB.
[[Page 68609]]
In a preliminary version of its DBS test procedure, NHTSA specified
a brake application rate of 320 mm/s. Feedback from industry suggested
this was too high, indicating it was at or near the application rate
used as the trigger for conventional brake assist. This is problematic
because the agency wants to provide NCAP credit for DBS, not for
conventional brake assist, if the vehicle is so-equipped. To address
this problem, the application rate was reduced to 7 in/s (178 mm/s) in
the June 2012 draft DBS test procedure. Feedback from vehicle
manufactures was that this reduction to 178 mm/s went too low. A system
able to activate DBS with such a brake application rate on the test
track may potentially result in unintended activations during real-
world driving. As an alternative, multiple vehicle manufacturers
suggested the application rate be increased to 10 in/s (254 25.4 mm/s). This value was implemented in the August 2014 draft
DBS test procedure.
The Euro NCAP procedure specifies a range of brake pedal
application speed of 7.9 to 15.8 in/s (200-400 mm/s). MBUSA noted that
values significantly above 14.2 in/s (360 mm/s) are more representative
of emergency braking situations and are addressed by conventional brake
assist not using forward looking sensor technology.
Information provided over the course of this program has caused us
to initially select a value less than 360 mm/s and greater than 178 mm/
s. We recommend 254 25.4 mm/s, and we have no substantive
basis to change this value again. Moreover, this value is well within
the range of the Euro NCAP specification. The value of 254 mm/s appears
a reasonable representation of the activation of DBS in an attempt to
stop, rather than slow down, but not fast enough to represent an
aggressive emergency panic stop of greater than 360 mm/s.
We are retaining the proposed values of 254 25.4 mm/s
(10 in/s 0.1 in/s) for the brake pedal application rate on
the DBS test.
(c) Brake Application Magnitude
The Alliance commented that the braking deceleration threshold
should be 0.4g (4.0 m/s\2\) or higher. Citing Euro NCAP's specification
for pedal displacement to generate a deceleration of 0.4g (4.0 m/s\2\),
The Alliance said using brake performance of at least 0.3g (3 m/s\2\)
deceleration as a threshold for DBS activation, as in the draft NCAP
test procedure, will lead to calibrations too sensitive and generate
excessive false positives or overreliance on the system.
The Alliance said the threshold for DBS intervention should be
toward the upper acceptable deceleration rates for adaptive cruise
control systems. These upper rates are up to 0.5g (5 m/s\2\) at lower
speeds and up to 0.35g (3.5 m/s\2\) at higher speeds. The Alliance
believes that a lower position for 0.3g (3 m/s\2\) will lead to
calibrations too sensitive in the real world and will generate
excessive false positives or overreliance on the system.
MBUSA said NHTSA's proposed magnitude of 0.3g (3 m/s\2\) more
closely resembles standard braking. It recommended brake pedal
application magnitude of near 0.4g (4 m/s\2\) that truly represents a
hazard braking situation. MBUSA said that according to its field test
data, the median brake amplitudes that occur ahead of real-world DBS
activations are closer to 0.425g (4.3 m/s\2\). MBUSA noted that for
Euro NCAP DBS testing, a brake magnitude of 0.4g (4 m/s\2\) is used.
The brake characterization process described in NHTSA's August 2014
draft DBS test procedure was intended to provide a simple, practical,
and objective way to determine the application magnitudes used for the
agency's DBS system evaluations. In this process, a programmable brake
controller slowly applies the SV brake with a pedal velocity of 1 in/s
(25 mm/s) from a speed of 45 mph (72 km/h). Linear regression is then
applied to the deceleration data from 0.25 to 0.55g to determine the
brake pedal displacement and application force needed to achieve 0.3g.
These steps are straight-forward and the per-vehicle output is very
repeatable. However, when these outputs are used in conjunction with
the brake pedal application rate used to evaluate DBS (i.e., rates ten
times faster than used for characterization), the actual decelerations
typically exceed 0.3g. Although this is not undesirable per se (crash
data suggest the braking realized just prior to a rear-end crash is
closer to 0.4g), the extent to which these differences exist has been
shown to depend on the interaction of vehicle, brake application
method, and test speed.\15\
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\15\ See http://www.Regulations.gov, NHTSA 2012-0057-0037.
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To address this concern, NHTSA has revised the characterization
process to include a series of iterative steps designed to more
accurately determine the brake application magnitudes capable of
achieving the same baseline (braking without the effect of DBS)
deceleration of 0.4g for all vehicles. The deceleration level is very
close to the deceleration observed just prior to many actual rear-end
crashes,\16\ and is consistent with the application magnitude used by
Euro NCAP during its test track-based DBS evaluations. Vehicle
manufacturers have told NHTSA that encouraging DBS systems designed to
activate in response to inputs capable of producing 0.4g, not 0.3g,
deceleration will reduce the potential for unintended DBS activations
from occurring during real-world driving.
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\16\ See http://www.Regulations.gov, NHTSA 2012-0057-0037.
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NHTSA will adopt its revised brake characterization process, and
include it as part of the DBS procedure. This process will ensure
baseline braking for each test speed, (25, 35, and 45 mph) will be
capable of producing 0.4 0.025g.
3. Use of Human Test Driver Versus Braking Robot
TRW advocated the use of a human driver in DBS testing to reduce
the test setup time and reduce the testing costs. Bosch supports the
test procedures as currently written calling for the use of a braking
robot in both CIB and DBS testing.
While the NHTSA AEB test procedures can be performed with human
drivers, satisfying the brake application specifications in the DBS
test procedures would be challenging for a human driver. The agency
acknowledges that some test drivers are capable of performing most or
all of the maneuvers in this program within the specifications in the
test procedures. However, we believe a programmable (i.e. robotic)
brake controller can more accurately reproduce the numerous braking
application specifications debated in this notice. Moreover, as these
technologies evolve and the algorithms are refined to create earlier,
more aggressive responses to pending crashes, while at the same time
avoiding false positives, the specifications for the test parameters
may become more complex and more precise. The agency will continue to
conduct all of the DBS NCAP tests using a brake robot.
Manufacturers, suppliers and test laboratories working for these
entities may choose not to use a brake robot, nor do they need to
follow the test procedures exactly. However they should be confident
their alternative methods demonstrate their systems will pass NHTSA's
tests because NHTSA will conduct confirmation testing as outlined
above. If a system fails NHTSA's confirmation testing, the
[[Page 68610]]
vehicle in question will not continue to receive credit for its DBS
system.
4. Brake Burnishing
NHTSA indicated we plan to use the brake burnishing procedure from
Federal Motor Vehicle Safety Standard (FMVSS) No. 135, ``Light vehicle
brake systems.'' IIHS said this is more pre-test brake applications
than is needed. IIHS said its research shows that brake performance can
be stabilized for AEB testing with considerably less effort. It cited a
test series of its own involving seven vehicle models with brand new
brakes in which AEB performance stabilized after conducting 60 or fewer
of the stops prescribed in FMVSS No. 135. IIHS said its AEB test
results after all 200 brake burnishing stops were not appreciably
different from those conducted after following the abbreviated
procedure described in FMVSS No. 126, ``Electronic stability control
systems.''
Ford urged NHTSA to adopt the Euro NCAP's brake burnishing
procedure and tire characterization from the Euro NCAP AEB protocol,
which it said can be completed in a few hours.
Tesla said the test procedures' specification for a full FMVSS No.
135 brake burnish is not clearly explained. They asked about how often
the burnishing had to be conducted and how the brakes are to be cooled.
FMVSS No. 135 ``Light vehicle brake systems'' is NHTSA's light
vehicle brake performance standard. The purpose of the standard is to
ensure safe braking performance under normal and emergency driving
conditions. The burnish procedure contained in FMVSS No. 135 is
designed to ensure the brakes perform at their optimum level for the
given test condition and to ensure that test result variability is
minimized. The burnish procedure in FMVSS No. 135 includes 200 stops
from a speed of 80 km/h (49.7 mph) with sufficient brake pedal force to
achieve a constant deceleration of 3.0 m/s\2\ (0.3g). It also specifies
a brake pad temperature range during testing.
The commenters suggested reducing the burnishing for two reasons.
First, they want to reduce the testing burden. The IIHS states that
their research shows that the foundation brake performance can be
stabilized after considerably less effort. Their testing showed
performance stabilization after 60 stops. Second, others want the
procedure to be harmonized with the Euro NCAP. The Euro NCAP brake
burnish procedure includes 13 stops total and a cool-down and is
otherwise identical to the brake conditioning in FMVSS No. 126.
The agency has considered these comments. The agency believes that
a full 200-stop burnishing procedure is critical to ensuring run-to-run
repeatability of braking performance during AEB testing and also
ensures that the vehicle's brakes performance does not change as the
test progresses. The intent of the 200-stop burnishing is deemed the
appropriate procedure for ensuring repeatability of brake performance
in FMVSS No. 135, the agency's light vehicle brake system safety
standard. The performance measured in these AEB tests relies on the
vehicle's braking system to reduce speed in order to mitigate or avoid
a crash with the test target. Since the agency has adopted the 200-stop
procedure as the benchmark for repeatable brake performance, dropping
the number of stops might create a repeatability situation for some
brake system designs and therefore a repeatability situation for some
AEB systems. Therefore, the agency will test AEB consistently with its
light vehicle brake system tests in FMVSS No. 135.
Tesla said the need for a full FMVSS No. 135 brake burnish is not
clearly explained. They interpreted the test procedure to specify brake
burnishing before each and every test run.
Tesla misunderstands the test procedure. NHTSA will perform the
200-stop brake burnish only one time prior to any testing unless any
brake system pads, rotors or drums are replaced, in which case the 200-
stop burnish will be repeated. After the initial burnish, additional
lower-speed brake applications are done only to bring the brake
temperatures up to the specified temperate range for testing.
Tesla also suggested that NHTSA should better explain how, and to
what extent, the agency expects the brakes to be cooled before
conducting each individual test run and series of runs. Tesla said
adding these cooling procedures will have test performance
implications.
The process of driving the vehicle until the brake cools below a
temperature between 65 [deg]C (149 [deg]F) and 100 [deg]C (212 [deg]F)
or drive the vehicle for 1.24 miles (2 km), whichever comes first, has
been an accepted practice in brake testing such as in FMVSS No. 135
testing. It is the brake temperature at the time of the test, not how
that temperature was obtained, that is the reportedly critical
characteristic in brake performance. Moreover, specifying an overly-
detailed procedure may not result in desired temperature. The amount of
heating or cooling may be affected by the vehicle design and the
ambient conditions of the testing. Alterations in the process may be
needed to achieve the temperature range.
For the AEB test procedures, NHTSA is maintaining its use of the
brake burnish procedure and the initial brake temperature range
currently used in its light vehicle brake standard, FMVSS No. 135.
5. Feasibility and Tolerances
TRW said the test procedures may not completely cover the control
and tolerance around the deceleration of the POV during the Lead
Vehicle Decelerating (LVD) portions of the test. It cited as an
example, that brakes were applied to a level providing deceleration of
0.3g with a tolerance of +/- 0.03g, but the ability to control that
parameter was not among the list of items used for the validity of test
criteria, nor is it present in the test procedure for how to monitor
and control that parameter for test validity.
The agency disagrees with TRW that the parameter was not among the
list of items used for the validity of a test criteria. The test
procedure for this parameter is described in the section titled ``POV
Brake Application. The test procedure provided details of this
specification, such as the beginning or onset of the deceleration
period, the nominal constant deceleration, the time to achieve the 0.3g
deceleration, and the average tolerance of the deceleration after the
nominal 0.3g deceleration is achieved, and the point at which the
measurement is finished. We believe TRW is stating that this
description of the deceleration parameters is not itemized in the list
of 10 items specified in the section ``SV Approach to the Decelerating
POV''. This list contains items that must be controlled during the
entire test, not just during the deceleration period. Since the
deceleration does not occur during the entire test we will not be
adding the specification to this list. The fact that the specifications
are listed makes these deceleration specifications necessary for a
valid test, even though the word ``valid'' does not appear in the
section called ``POV Brake Application''.
TRW states that the test procedures do not specify how the test
laboratory will monitor the declaration parameters. NHTSA has
recommended in Table 2 of the test procedures that the contractor will
need to have an accelerometer to measure the longitudinal deceleration
of the SV and POV. These instrumentation recommendations include
specifications for the range, resolution and accuracy of these
instruments. The test procedure does not specify how the contractor is
to monitor or control the acceleration
[[Page 68611]]
during this test. As much as possible, the agency specifies performance
specifications, not design specifications. We depend on the expertise
of the contractor to achieve these performance goals. We then monitor
the output of this performance.
6. Lead Vehicle Stopped Tests (Scenarios)
MEMA supported the planned AEB test scenarios as representative of
typical, real[hyphen]world driving occurrences. It said the scenarios
are appropriate ways to evaluate CIB and DBS systems.
The Alliance said the lead vehicle stopped test should be deleted
and the agency should only uses the lead vehicle deceleration to a stop
test because 50 percent of police-reported cases rear-end crashes coded
as lead stopped vehicle are actually lead vehicle decelerating to a
stop. They argued such a change would permit more affordable systems
and would reduce false activations.
In the August 2014 research report,\17\ we adjusted estimates of
AEB-relevant rear-end crashes by splitting the estimated number of
police-reported lead-vehicle-stopped crashes evenly between lead
vehicle stopped and lead vehicle decelerating to a stop. This change
was made based on comments to the 2013 AEB request for comments and
additional analysis of the crash data.
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\17\ http://www.Regulations.gov, Docket NHTSA-2012-0057-0037.
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The use of the lead stopped vehicle scenarios is very important.
Even if 50 percent of the lead-vehicle stopped crashes are re-
classified as lead vehicle decelerating to a stop, hundreds of
thousands of lead-vehicle stopped crashes still occur each year. For
this reason, and to be consistent with the Euro NCAP tests, NHTSA does
not believe it is appropriate to exclude the lead-vehicle stopped
scenario from the CIB and DBS performance evaluation.
Based on the test track testing we have conducted since 2013, we
have found that vehicles able to satisfy our LVS evaluation criteria
also do so for the LVD-S test scenario. However, not all vehicles that
pass our LVD-S pass the LVS scenarios.
Therefore we have decided to reduce the test burden by removing the
lead vehicle deceleration to a stop (LVD-S) test and retaining the lead
vehicle stopped (LVS) test.
7. False Positive Tests (Scenarios)
AGA, ASC and TRW said only radar-based AEB systems will react to
NHTSA's steel trench plate based false positive test, whereas other
types of systems, camera- and lidar-based for example, will not be
affected. AGA said that unless a test that could challenge both camera
and radar systems can be identified, the false positive test should be
dropped. MEMA also noted that since radar systems are sensitive to the
steel trench plate false positive test, this may impact the comparative
nature of radar versus other systems such as camera or lidar sensors.
MEMA encouraged NHTSA to evaluate the procedure and continue to make
further improvements to avoid any potential test bias.
TRW suggested two other possible false positive tests, one that
would reflect ``the most typically observed false-positive AEB event''
a dynamic passing situation and the other in which the test vehicle
drives between two stationary vehicles. Bosch said there is no single
test that will fully address the problem of false activations.
The Crash Avoidance Metrics Partnership (CAMP) Crash Imminent
Braking (CIB) Consortium endeavored to define minimum performance
specifications and objective tests for vehicles equipped with FCW and
CIB systems. While assessing the performance of various system
configurations and capabilities, the CAMP CIB Consortium also
identified real-world scenarios capable of eliciting a CIB false
positive.\18\ Additionally, two scenarios from an ISO 22839
``Intelligent transport systems--forward vehicle collision mitigation
systems--Operation, performance, and verification requirements''
(draft) were used to evaluate false positive tests, two tests with
vehicles in an adjacent lane. The CAMP study originally documented real
world situations that could be used to challenge the performance of the
systems, such as an object in roadway, an object in a roadway at a
curve entrance or exit, a roadside stationary object, overhead signs,
bridges, short radius turns, non-vehicle and vehicle shadows, and
target vehicles turning away.\19\ NHTSA performed a test program of six
of the CAMP-identified scenarios that could produce a positive. The
eight maneuvers selected and tested by NHTSA in considering a false-
positive test were decelerating vehicle in an adjacent lane--straight
road, decelerating vehicle in an adjacent lane--curved road, driving
under an overhead bridge, driving over Botts' Dots in the roadway,
driving over a steel trench plate, a stationary vehicle at a curve
entrance, a stationary vehicle at a curve exit, and a stationary
roadside vehicle.
---------------------------------------------------------------------------
\18\ ``Evaluation of CIB System Susceptibility to Non-
Threatening Driving Scenarios on the Test Track'', July 2013, DOT HS
811 795.
\19\ ``Objective Tests for Automatic Crash Imminent Braking
(CIB) Systems Appendices Volume 2 of 2'', September 2011, DOT HS 811
521A.
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During testing we found that all CIB activations presently known by
NHTSA are either preceded by or are coincident with FCW alerts. For the
testing, we use the FCW warning as a surrogate for the CIB and DBS
activations. Of the maneuvers used in the study, FCW activations were
observed during the conduct of four scenarios: Object in roadway--steel
trench plate, stationary vehicle at curve entrance, stationary roadside
vehicles, and decelerating vehicle in an adjacent lane of a curve. Of
the maneuvers capable of producing an FCW alert, CIB false positives
were observed only during certain Object in Roadway--Steel Trench Plate
tests, and for only one vehicle. The vehicle producing the CIB false-
positives did so for 100 percent of the object in roadway--steel trench
plate tests trials. No FCW or CIB activations were observed during the
decelerating vehicle in an adjacent lane (straight), driving under an
overhead bridge, objects in roadway--Botts' Dots, and stationary
vehicle at curve exit maneuvers.
The steel trench plate was the easiest to set up, the least complex
to perform, and a realistic test because the scenario is encountered
during real world driving. Also, the steel trench plates are similar to
some metal gratings found on bridges. The steel trench plate used in
this program is believed to impose similar demands on the system
functionality, albeit with better test track practicality (i.e., cost,
expediency, and availability).
Both the agency and some commenters believe that a false-positive
test should be included in this program. Conversely, commenters state
that the steel trench plate test is biased against radar systems.
The agency will retain the steel trench plate false-positive test
in this program and will continue to monitor vehicle owner complaints
of false positive activations. The agency has received consumer
complaints of false-positives of these AEB systems. This program should
make an effort to reduce false-positives in the field. We believe a
false-positive test is important to be included in the performance
tests for these technologies. We disagree that the steel trench plate
is biased against radar systems. The agency establishes performance-
based tests. The purpose of the performance specifications in this
program is to discern and discourage systems that do not perform
sufficiently in real-world scenarios. If the steel trench plate
identifies a notable
[[Page 68612]]
performance weakness in system, that weakness should be pointed out to
consumers.
It is impossible to recreate every possible source of false-
positive activations experienced during real-world driving. The steel
trench plate tests are included as one significant common source of
false positives during our CIB and DBS test track evaluations. We
encourage vehicle manufactures to include identified false-positive
scenarios in system development. If in the future, other scenarios
become prevalent and are brought to our attention through consumer
complaints, we will consider including them in our test protocol.
8. Steel Plate Weight
Noting that the steel trench plate currently specified in the test
weighs 1.7 tons and is difficult to put in place, AGA urged the agency
to allow an alternative plate if manufacturers can verify its
performance. Concerning the weight of the steel trench plate, the test
procedures do not specify this plate to be positioned on a part of the
test track used for other tests. The plate is not installed or
embedded, merely laid on top of a road surface. We do not see a need to
be concerned with weight or the size of this test item. We are not
developing a lighter weight version of this plate at this time.
9. DBS False Activation Test Brake Release
The Alliance requested that the brake application protocol and
equipment for the DBS steel trench plate scenario test procedure should
provide specification for a pedal release by the driver during the
false positive test. The Alliance states that some systems have
mechanisms that allow the driver to release the DBS response if a false
activation occurs. One of the simplest and most intuitive mechanisms is
for the driver to release the brake pedal. This is not in the DBS false
positive test.
The agency does not agree with the Alliance's recommendation that a
way for the driver to override false positives should be provided in
the test scenario. The purpose of the false-positive test is to ensure
that they do not occur during this performance test. If the vehicle's
DBS system activates in reaction to the steel trench plate, then this
is the kind of false-positive for which the test procedure is designed
to identify. The agency feels that the potential consequences of a
false positive are sufficient to warrant a test failure.
The agency has decided not to add a brake release action to the
false-positive test procedures.
10. CIB False Activation Test Pass/Fail Criteria
The Alliance and Bosch commented that the allowable CIB steel plate
test deceleration threshold of 0.25g was too low. Bosch and the
Alliance observed that some current state-of-the-art forward collision
warning (FCW) portion of these AEB systems in the market use a brake
jerk to warn the driver. The majority of the current brake-jerk
applications for FCW use a range of 0.3g-0.4g and the maximum speed
reduction normally does not exceed 3 mph (5 km/h), Bosch said. Bosch
suggested increasing the threshold of the CIB false activation failure
to 0.4g or using a maximum speed reduction, rather than peak
deceleration rate, as the key factor for determining a pass/fail result
for this test. Setting the fail point of the false activation test at
0.25g would restrict haptic pedal warning design to below 0.25g.
The steel plate test is intended to evaluate CIB performance. This
test is not intended to evaluate a haptic FCW capable of producing a
peak deceleration of at least 0.25g before completion of the test
maneuver. To make this distinction clear, we will raise the false
positive threshold to a peak deceleration of 0.50g for CIB, and 150
percent of that realized with foundation brakes during baseline braking
for DBS.
11. Pass/Fail Criteria for the Performance Tests
The Alliance, Honda, AGA and Ford said that the determination that
AEB technologies will pass each of the tests in the test procedure
seven out of eight times should be changed to be consistent with the
five passes out of seven trials that is specified by the NCAP forward
collision warning (FCW) test procedures. The Alliance and Ford noted
that the agency did not provide data to support the seven out of eight
criterion approach. Ford presented the results of a coin toss
experiment, which it said indicated that the five out of seven criteria
covers 93.8 percent of all possible outcomes, a level whose robustness
compares favorably to the 99.6 percent of all possible outcomes covered
by the seven out of eight criterion.
Tesla said the planned test procedures include too many tests.
NHTSA notes that for the FCW NCAP, the vehicle must pass five out
of seven trials of a specific test scenario, to pass that scenario. The
vehicle must pass all scenarios to be recommended.
The agency believes the current FCW test procedure criterion of
passing five out of seven tests has successfully discriminated between
functional systems versus non-functional systems. Allowing two failures
out of seven attempts affords some flexibility in including emerging
technologies into the NCAP program. For example, NHTSA test
laboratories have experienced unpredictable vehicle responses, due to
the vehicle algorithm designs, rather than the test protocol. Test
laboratories have seen systems that improve their performance with use,
systems degrading and shutting down when they do not see other cars,
and systems failing to re-activate if the vehicle is not cycled through
an ignition cycle.
To be in better alignment with the FCW NCAP tests, we are changing
the pass rate for the CIB and DBS tests used for NCAP to five out of
seven tests within a scenario.
12. Vehicle Test Weight/Weight-Distribution
AGA said the current test protocol allows testing a vehicle up to
the vehicle's gross vehicle weight rating (GVWR). The Alliance noted
that the Euro NCAP AEB test protocol defines the vehicle weight
condition as 1% of the sum of the unladen curb mass, plus
440 lb (200 kg). AGA asked that the test protocol be amended to include
an upper weight limit, similar to the way that Euro NCAP's AEB test
specifies the vehicle to be loaded with no more than 440 lb (200 kg).
Specifically, the Alliance recommended replacing the current language
in Section 8.3.7 of the current CIB and DBS test procedures with:
``7. The vehicle weight shall be within 1% of the sum of the
unloaded vehicle weight (UVW) plus 200kg comprised of driver,
instrumentation, experimenter (if required), and ballast as
required. The front/rear axle load distribution shall be within 5%
of that of the original UVW plus 100% fuel load. Where required,
ballast shall be placed on the floor behind the passenger front seat
or if necessary in the front passenger foot well area. All ballast
shall be secured in a way that prevents it from becoming dislodged
during test conduct.''
The agency inventoried the current loads used at our test
laboratory. The instrumentation and equipment currently used weighs
approximately 170 lb (77 kg). Allowing two occupants in the vehicle
could push the total load over 440 lb (200 kg) upper bound suggested by
AGA and he Alliance.
The agency would like to reserve the flexibility of having an
additional person in the vehicle during testing to assist in the
testing process, observe the tests and perhaps train on the testing
[[Page 68613]]
process. Also, we measured the effects of our standard load of one
driver plus the instrumentation and equipment on weight distribution,
and found that the percentage of weight on the front axle tended to
increase by about 1 percent, on average. We assume adding a passenger
in the rear seat would be approximately the same. This is well within
the 5 percent variance from the unloaded weight as suggested by the
Alliance.
We have considered the comments that vehicle weight and weight
distribution will have a large effect on the performance of CIB
systems. We believe that this comment concerns both the vehicle sensing
system alignment and braking performance repeatability. If it is true
that weight and weight distribution consistent with predictable
consumer usage have a large effect on the performance of CIB systems,
this is a concern of the reliability of these systems to consumers.
The agency will specify a maximum of 610 lb (277 kg) loading in
these test programs. This will allow some test equipment and personnel
flexibility, while still maintaining some reasonable cap on the loading
changes. We also note that we may raise this limit on a case-by-case
basis and in consultation with the vehicle manufacturer, if there is a
need for additional equipment or an additional person that we have not
anticipated at this time.
13. Lateral Offset of SV and SSV; Test Vehicle Yaw Rate
AGA urged the agency to adopt the +/-1 ft (0.3 m) lateral offset
and 1 degree per second yaw rate specifications that were in previous
versions of the test procedures as opposed to the +/-2 ft (0.6 m) in
the latest version to improve test accuracy and better reflect
anticipated real world conditions. DENSO agreed that the 1 foot lateral
offset (0.3 m) and 1 degree per second yaw rate should be restored.
MEMA also noted the change in yaw and lateral orientation of the SV and
POV from the 2012 draft test procedures to the 2014 test procedure
draft and asked for clarification. The Alliance noted that the
allowable vehicle yaw rate in each test run has been increased to +/-2
degrees per second from +/-1 degree per second in the previous versions
of the test procedures. Bosch recommended that NHTSA consider using a
steering robot or some other means of controlling the lateral offset.
Confirming this tolerance range may be difficult with the ADAC EVT
surrogate used by Euro NCAP and other institutions because the
surrogate's position relative to the road or the subject vehicle is not
directly measured. The measurement equipment is stored in the tow
vehicle, not in the ADAC surrogate.
Review of the NHTSA's 2014 AEB test data indicate that decreasing
the lateral displacement tolerance from 2 ft to 1 ft (0.6 m to 0.3 m) should not be
problematic. Of the 491 tests performed, only 13 (2.7 percent) had SV
lateral deviations greater than 1 ft (0.3 m). Those that did ranged
from 1.06 to 1.21 ft (0.32 m to 0.37 m). The use of the SSV monorail
makes conducting the test within the allowable 1-ft lateral
displacement this feasible because the SSV position is controlled by
the monorail.
Through testing conducted by the NCAP contractor, we have
determined that we should be able to satisfy the tighter tolerance.
Testing performed by NHTSA's VRTC support this finding. We believe we
can perform this testing with a human driver steering the vehicle,
rather than a steering robot.
For SV yaw rate, we will tighten the test tolerance to 1 deg/sec. For the SV and POV, we will tighten the test tolerance
to 1 ft (0.3 m) relative to the center of the
travel lane. The lateral tolerance between the centerline of the SV and
the centerline of the POV will be tightened to 1 ft (0.3
m). Additionally, we will be filtering these data channels with a 3 Hz
digital filter (versus the 6 Hz used previously) to eliminate short
duration data spikes that would invalidate runs that are otherwise
valid. We are also eliminating the lateral offset and yaw rate validity
specifications for the brake characterization (12.2.1.5 and 6) and
false positive baseline tests (12.6.1.5 and 6) of the DBS test
procedure. This data is not needed to ensure detection and braking
repeatability; with no POV in these tests, it is not necessary to be in
the exact center of the lane, for example.
14. Headway Tolerance
Subaru recommended in its comment that NHTSA adopt a headway
tolerance of 5 ft (1.5 m) in the test procedures. No explanation of why
this is needed was provided in the comments. The headway tolerance is
the allowable variance in the longitudinal distance between the front
of the subject vehicle and the rear of the principal other vehicle
ahead of it as the two vehicles move. The current tolerance is 8 ft (2.4 m).
A review of our test data reveals a 5 feet (1.5 m) tolerance is too
tight unless the agency were committed to fully-automated AEB testing
is conducted. At this time we do not plan to fully automate the two
test vehicles (the SV and the vehicle towing the POV). The 8 ft (2.4 m)
tolerance currently specified in our AEB procedures for the LVD tests
is the same used for FCW NCAP testing. We are not aware of this
tolerance causing any problems in AEB testing. We will leave the
tolerance at 8 ft (2.4 m).
15. Speed Range, Upper and Lower Limits
The Alliance, AGA, Continental, Ford, Honda, IIHS, and MBUSA said
the activation limits of the test procedures are too high at the upper
end and too low at the lower end or otherwise took issue with the speed
parameters of the test procedures.
AGA objected to specifying systems to operate up to 99.4 mph,
noting that 80 percent of crashes covered by these systems occur at
speeds of 50 mph or less. The high speed will preclude systems that are
very effective and will create safety hazards for test drivers and test
tracks, AGA added.
Continental said although it is listed as a definition, the CIB/DBS
active speed range is described as a performance specification, which
they said makes it unclear if NHTSA's intent that the definition speed
range must be met in order to receive the NCAP recommendation. If this
is the case Continental said it would be necessary to define the
associated performance criteria to meet the specification that the
system must remain active, especially at the maximum speed, to achieve
the balance between effectiveness and false positives at these
specified higher speeds.
As suggested by Continental's comments, the upper and lower
activation limits were intended to define the AEB systems under
consideration. There is no need to define these systems in the test
procedure with a reference to their upper and lower activation limits.
The agency hopes that the systems made available on light vehicles sold
in the United States will be active at these speeds. However, the
primary focus is to assure that AEB systems meet the specifications of
the test procedures and activate at the speeds at which an AEB system
can reasonably be expected to avoid or mitigate a rear end crash.
Therefore, the references to the upper and lower activation limits will
be removed from the NCAP AEB test procedures.
16. DBS Throttle Release Specification
The Alliance states the current throttle release specification
within 0.5 seconds from the onset of the FCW warning will result in
test results that
[[Page 68614]]
are different between manufacturers. This specification in the DBS test
procedure was established to simulate the human action of removing the
foot from the throttle and placing it on the brake. In the test setup,
the test driver releases the throttle at a specific time to collision
relative to the DBS brake robot braking initiating the brake
application. System design strategies across manufacturers vary on how
to ascertain when a driver needs assistance and are often based on
driver inputs on the steering wheel and pedals. The Alliance suggests
that to avoid future interference with the optimization of warning
development, we should consider other options.
The Alliance requested that the agency consider the following
options:
Maintain Throttle Position to the Onset of Brake Application: The
agency believes this is not possible for vehicles such as the Infiniti
Q50. For this vehicle, part of the FCW is a haptic throttle pedal that
pushes back up against the driver's foot. This change in pedal position
would violate a constant pedal position criterion. While it may be
possible to hold the throttle pedal position fixed with robotic
control, NHTSA has not actually evaluated the concept, and the agency
does not plan to use a robot on subject vehicle throttle applications
during the FCW and/or AEB performance testing.
Throttle Release Relative to a Braking Initiation Time to Collision
(TTC): In this approach the driver monitors the SV-to-POV headway, and
responds at the correct instant. Although NHTSA has experience with
this technique,\20\ the agency has concerns about incorporating it into
the LVS, LVM, and LVD scenarios used to evaluate DBS because the agency
does not intend to automate SV throttle applications for these tests.
Since the brake applications specified in NHTSA's DBS test procedure
are each initiated at a specific TTC, this approach would also cause
the throttle release to occur at a specific TTC. If this causes the
commanded throttle release occur after the FCW is presented, it may not
be possible for the driver to maintain a constant throttle pedal
position between issuance of the FCW and the commanded throttle release
point. The driver maintaining a constant throttle may result in the SV-
to-POV headway distance changing and move out of the specified headway
tolerance. While this may be possible with robotic control of the
throttle, NHTSA has not actually evaluated the concept.
---------------------------------------------------------------------------
\20\ NHTSA's false positive DBS tests are performed in the
presence of the steel trench plate, since this plate does not cause
the FCW to activate for many light vehicles, the DBS test procedure
includes a provision for the SV driver to release the throttle at a
fixed TTC if the FCW does not activate before a TTC = 2.1s.
---------------------------------------------------------------------------
OEM Defined Throttle Release Timing: NHTSA would like to minimize
vehicle manufacturers' input on how their vehicles should be evaluated.
The agency will not make a test procedure change at this time. We
believe it is possible for the SV driver to repeatably release the
throttle pedal within 0.5 s of the FCW, and that any reduction of
vehicle speed between the time of the throttle pedal release and the
onset of the brake application is within the test procedure
specifications. Human factors research indicates that when presented
with an FCW in a rear-end crash scenario, driver's typically (1)
release the throttle pedal then (2) apply the brakes.\21\ Therefore,
the speed reduction that occurs between these two points in time has
strong real-world relevance.
---------------------------------------------------------------------------
\21\ ``Development of an FCW Algorithm Evaluation Methodology
With Evaluation of Three Alert Algorithms--Final Report,'' June 2009
Figure 5. DOT HS 811 145
---------------------------------------------------------------------------
D. Suggested Additions to Test Procedures
1. Accounting for Regenerative Braking
Tesla expressed concern that the test procedures as currently
written do not account for totally or partially electric vehicles that
utilize regenerative braking to recharge batteries. Tesla urged NHTSA
to clarify protocols for EV and hybrid vehicles, specifically regarding
regenerative braking.
Regenerative braking is an energy-preservation system used to
convert kinetic (movement) energy back to another form, which in the
case of an electric vehicle, is used to charge the battery. The reason
it is called ``braking'' is that the vehicle is forced to decelerate by
this regenerative system, once the driver's foot is taken off of the
throttle. This system is independent of the standard brake system but
the result is the same; the vehicle slows down.
NHTSA's direct experience with testing a vehicle equipped with AEB
and regenerative braking has been limited to the BMW i3. As expected,
once the driver released the throttle pedal in response the FCW alert,
regenerative braking did indeed slow the vehicle at a greater rate than
for other vehicles not so equipped with regenerative braking. This had
the effect of reducing maneuver severity since the SV speed at the time
of AEB intervention was less than for vehicles not so-equipped. This is
not considered problematic.
For vehicles where the driver can select the magnitude of the
vehicle's regenerative braking (e.g., the Tesla Model S), the vehicle's
AEB system will be evaluated in its default mode (as originally
configured by the vehicle manufacturer).
2. Customer-Adjustable FCW Settings
The Alliance noted that in some CIB and DBS applications, system
performance may take into account the warning timing setting of the FCW
system when the FCW system allows the consumer to manually set the
warning threshold. To clarify, the Alliance recommended that the
following language, which is adapted from the FCW NCAP test procedure
(Section 12.0), be included in the CIB and DBS NCAP test procedure:
``If the FCW system provides a warning timing adjustment for the
driver, at least one setting must meet the criterion of the test
procedure.''
In its previous work involving FCW, the agency has allowed vehicle
manufacturers to configure the systems with multiple performance level
modes. This provided vehicle manufacturers flexibility in designing
consumer acceptable configurations. The test procedure allowed an FCW
mode that provides the earliest alert if the timing can be selected and
used during agency testing. Additionally, the test procedures do not
include resetting to the original setting after ignition cycles.
NHTSA believes that as a consumer information program, we should
test the vehicles as delivered. We also believe the performance level
settings of the FCW systems within the AEB test program should now be
set similar to the AEB. The Alliance requested that we have language in
the test procedure specifying that if there are adjustments to the FCW
system, one setting must meet the criterion of the test procedure.
Vehicle manufacturers may provide multiple settings for the FCW
systems. However, the agency will only use the factory default setting
for both the FCW and the AEB systems in the AEB program.
3. Sensor Axis Re-Alignment
The Alliance commented that when the SV hits the SSV in some
trials, the impact may misalign the system's sensors. To ensure
baseline performance in each trial, the Alliance asked that the test
procedure be modified to allow the vehicle manufacturer representatives
or test technicians to inspect and, if needed, re-align the sensor axis
after each instance of contact between the subject vehicle and the SSV.
[[Page 68615]]
NHTSA has seen two cases of sensor misalignment during the initial
development of this program. In one case, the subject vehicle had
visible grill damage because the AEB system did not activate and the
test vehicle hit the SSV at full speed. In another case, the vehicle
sensing system shut down after numerous runs; inspection also revealed
visible grill damage to the subject vehicle. In both cases, the
vehicles were returned to an authorized dealer, repaired and then
returned to the test facility.
The NCAP test program has instituted two new procedural
improvements to monitor for system damage. First, we began testing with
less-severe tests, such as the lead vehicle moving test first, to
determine if the vehicle system is capable of passing any of the tests.
Second, we have instituted more rigorous visual between-vehicle
inspections by the contractor during the testing. Based on our
observations in testing, we believe systems that have sensor damage
will likely show visible grill damage.
With the improvements in the AEB systems and refinement of our test
protocol, we do not believe sensor misalignments will be a significant
problem. We invite vehicle manufacturer representatives to attend each
of our tests. We reserve the right to work with the vehicle
manufacturers on a one-on-one basis if we have problems with the
vehicles during the tests.
4. Multiple Events--Minimum and Maximum Time Between Events
The Alliance and Ford asked that the AEB test procedures specify a
minimum time of 90 seconds and a maximum time of 10 minutes between
each test run as in Euro NCAP AEBS test procedures. Some AEB systems
initiate a fail-safe suppression mechanism when multiple activations
are triggered in a short time. Most systems can be activated again with
an ignition key cycle. In most cases activation of the suppression
mechanism can be avoided by including a time interval between
individual AEB activations or by cycling the ignition. The current test
procedure addresses this by checking for diagnostic test codes (DTCs)
to determine if any system suppression or error codes have occurred
with the sensing system software.
The agency agrees that there should be a minimum of 90 seconds
between test runs and will modify the AEB test procedures to state this
explicitly. We recognize that the algorithms in these vehicles look for
conditions that are illogical, such as multiple activations in short
periods of time, and within a single ignition cycle. The time needed to
allow the subject vehicle brakes to cool and the test equipment to be
reset between each test trial has always exceeded 90 seconds in the
agency's testing experience. The agency will also specify in the test
procedures that the vehicle ignition be cycled after every test run.
The agency believes a maximum time between test runs of 10 minutes
is too short to be feasible. The test engineers need sufficient time to
review data, inspect the test equipment and set up for the next test
run. Also recall that the test engineers need time to ensure the
vehicle brake temperatures are within specification and the brake
system is ready for the next test run. Additionally, it is impractical
to specify that all of the tests must be completed within 10 minute
cycles while conversely specify that testing be discontinued if ambient
conditions are out of specifications. At this time, we are unaware of
any algorithm-based reason why testing must be resumed in less than 10
minutes.
5. Time-to-Collision (TTC) Definition
The Alliance observed that the TTC values used in the test
procedures are calculated in the same manner as they are in the current
NCAP FCW test procedure, but noted that the TTC calculation equations
are not included in the draft CIB and DBS test procedures. The Alliance
asked that, for clarification purposes, the TTC equations that appear
in Section 17.0 of the NHTSA NCAP FCW test procedure dated February
2013 be added to the CIB and DBS test procedures.
The agency acknowledges that the TTC calculations for the FCW test
procedure are the same as these test procedures. The TTC calculations
that are included in the NCAP FCW test procedures will be added to the
AEB test procedures, as requested in the comments. This will make it
clear that the TTC equations apply to the AEB test procedures as well.
E. Strikeable Surrogate Vehicle (SSV)
1. Harmonization Urged
NHTSA's strikeable surrogate vehicle (SSV) was discussed earlier in
this notice. Multiple commenters encouraged NHTSA to harmonize with
Euro NCAP and to use the ADAC EVT in lieu of the SSV. The commenters
had concerns about the use of the SSV. They asked NHTSA to establish a
maintenance process for the SSV. They questioned whether parts such as
the MY 2011 Ford Fiesta vehicle's taillights, rear bumper reflectors
and third brake light can be a part of the SSV indefinitely (i.e., will
parts continue to be built). The Alliance, Ford, and Continental took a
moderate position, supporting calls for harmonization but acknowledging
all the work that went into developing the SSV. Other commenters
proposed NHTSA could potentially use the SSV target in conjunction with
the EVT propulsion system used by Euro NCAP. Concern was also expressed
over the SSV setup, the number of facilities capable of performing the
actual test maneuvers, the additional test costs, and the problem of
damage to the subject vehicles.
AGA said NHTSA could provide an option for manufacturers to use an
alternative test devices of Euro NCAP or IIHS. Both Euro NCAP and IIHA
use ADAC EVT.
Tail light availability is not expected to be a problem for the
foreseeable future. However, if this should this become an issue,
simulated taillights, an updated SSV shell, or potentially other
changes could be made to replace the current model.
Overall, the AEB system sensors interpret the SSV appears to
sensors as a genuine vehicle. Nearly all vehicle manufacturers and many
suppliers have assessed how the SSV appears to the sensors used for
their AEB systems. The results of these scans have been very favorable.
Although the SSV has been designed to be as durable as possible,
its various components may need to be repaired or replaced over time.
As with all other known surrogate vehicles used for AEB testing, the
frequency of repair or replacement is strongly dependent on how the
surrogate is used, particularly the number of high speed impacts
sustained during testing.
With regards to availability, the specifications needed to
construct the SSV are in the public domain.\22\ Multiple sets of the
SSV and the tow system have been manufactured and sold to vehicle
manufactures and test facilities. The SSV can be manufactured by anyone
using these specifications. With regard to other issues like cost and
convenience of use, we feel the SSV is within the range of practicality
as a test system. In relation to other motor vehicle test systems, the
SSV system is reasonably priced and can be moved from test facility to
test facility.
---------------------------------------------------------------------------
\22\ http://www.regulations.gov, Docket NHTSA-2012-0057.
---------------------------------------------------------------------------
While we appreciate the concerns about the SSV expressed in the
comments, we will continue to specify
[[Page 68616]]
the SSV in the NCAP AEB test procedures that NHTSA will use to confirm
through spot checks that vehicles with AEB technologies and for which a
manufacturer has submitted supporting data meet NCAP performance
criteria. As noted previously this does not require use of the SSV by
manufacturers for their own testing.
2. Repeatability/Reproducibility
The Alliance said because the SSV is not readily available, its
members have not been able to conduct a full set of tests to assess the
repeatability and reproducibility of the SSV in comparison with other
commercially available test targets.
NHTSA is aware that the SSV is a relatively new test device and
that every interested entity may not have had a chance to perform a
comprehensive series of SSV evaluations or seen how it is actually
used. However the specifications needed to construct the SSV are in the
public domain and multiple SSVs have been manufactured and sold to
vehicle manufacturers and test facilities. A test report describing the
SSV repeatability work performed with a Jeep Grand Cherokee has
recently been released.\23\
---------------------------------------------------------------------------
\23\ Forkenbrock, GJ & Snyder, AS (2015, May) NHTSA's 2014
Automatic Emergency Braking (AEB) Test Track Evaluation (Report No.
DOT HS 812 166). Washington DC, National Highway Traffic Safety
Administration.
---------------------------------------------------------------------------
3. Lateral Restraint Track (LRT)
Commenters were concerned with the lateral restraint track (LRT).
They felt the LRT was not needed. The permanent installation of the LRT
used up track space and made it hard to move testing activities to
another test track.
Some commenters indicated that if the LRT used to keep the SSV
centered in its travel lane is white, it may affect AEB performance.
This is because some camera-based AEB systems consider lane width in
their control algorithms, and these algorithms may not perform
correctly if the LRT is confused for a solid white lane line. Although
NHTSA test data does not appear to indicate this is a common problem,
the NHTSA test contractor is using a black LRT to address this
potential issue. The black LRT appears more like a uniform tar strip
that has been used to seal a long crack in the center of the travel
lane pavement, a feature present on real-world roads.
NHTSA appreciates these concerns but believes the continued use of
the LRT is important. LRT is designed to insure several things,
including that the SSV will be constrained within a tight tolerance to
optimize test accuracy and repeatability. Using the LRT to absolutely
keep the path of the SSV within the center of the lane of travel, in
conjunction with the lateral tolerances defined in the CIB and DBS test
procedures, will allow the agency to test AEB systems in a situation
where one vehicle is approached by another vehicle from directly
behind. To reduce the potential for unnecessary interventions, some AEB
systems contain algorithms that can adjust onset of the automatic brake
activation as a function of lateral deviation from the center of the
POV. This is because it will take less time for the driver to steer
around the POV if the lateral position of the SV is biased away from
its centerline. Although this may help to minimize nuisance activations
in the real-world, the same algorithms may contribute to test
variability during AEB NCAP evaluations if excessive lateral offset
exists between the SV and POV. Since the use of the LRT prevents this
from occurring, it is expected the agency's tests will allow AEB
systems to best demonstrate their crash avoidance or mitigate
capabilities.
Ford suggested that NHTSA use the ADAC EVT propulsion system with
the SSV to increase feasibility for manufacturers. NHTSA believe the
inherent design differences between the SSV and ADAC surrogates makes
using the ADAC EVT propulsion system with the SSV a considerable
challenge. Design changes to the SSV and/or ADAC EVT rig would be
needed. It is not possible to simply substitute the SSV for the ADAC
EVT surrogate on the ADAC rig as Ford suggests. Even if the ADAC EVT
could be adapted, and even though it appears to track well behind a tow
vehicle, the precise position of the ADAC EVT is not measured, so the
lateral offset cannot be quantified.
Commenters expressed concern on the allowable lateral offset and
yaw rate tolerance in the AEB test procedures placing considerable
emphasis on the importance of narrowing the tolerances in these areas.
AGA said the lateral offset and yaw rate in August 2014 draft test
procedures (+/- 2 ft (0.3 m) lateral offset and +/- 2 deg/s yaw rate)
can create a delay in AEB system response that could affect a system's
performance during and AEB test. DENSO agreed that a higher tolerance
in lateral offset and yaw rate tends to decrease forward looking sensor
detection performance. The Alliance too weighed in on this saying, that
``the variability in lateral offset is expected to have a significant
impact on test reproducibility and system performance and resultant
rating,'' adding that the yaw rate should be +/- 1 deg/s to be
consistent with the FCW test procedure given the fact that AEB systems
use the same sensors as FCW systems. As discussed earlier, we have
agreed to tighten the yaw rate and lateral offset tolerance. This makes
the tight control provided by the LRT even more important to the
performance of these tests.
Until the agency has an indication that an alternative approach to
moving the SSV down a test track can ensure the narrow tolerances for
lateral offset and yaw rate, the LRT will remain in the AEB test
procedures. Our contractor has already installed a black LRT. Thought
this does not completely disguise the restraint track, it is close to
being masked for a camera-based AEB system.
4. What is the rear of the SSV? (Zero Position)
NHTSA considers the rearmost portion of the SSV, or the ``zero
position,'' to be the back of the foam bumper. The Alliance suggested
the rearmost part of the SSV should be defined by its carbon fiber
body, not its foam bumper. The Alliance said it has observed SV-to-SSV
measurement errors of as much as 40 cm (15.7 in), and attributes them
to their vehicle's sensors not being able to consistently detect the
reflective panel located between the SSV's bumper foam and its cover.
It has always been the agency's intention to make the rear of the
SSV foam bumper detectable to radar while still having its radar return
characteristics be as realistic as possible. This is the reason NHTSA
installed a radar-reflective panel between the SSV's 8 in (20.3 cm)
deep foam bumper and its cover; the panel is specifically used to help
radar-based systems define the rearmost part of the SSV since the foam
is essentially invisible to radar. We are presently working to identify
the extent to which AEB systems have problems determining the overall
rearmost position of the SSV. NHTSA considers the outside rear surface
of foam bumper, immediately adjacent to the radar-reflective material
to be the ``zero position'' in its CIB and DBS tests, and is
considering ways to better allow AEB systems to identify it.
5. Energy Absorption, Radar System Bias
Other concerns mentioned by commenters include design changes to
the SSV: Increasing energy absorption and minimizing a perceived bias
towards radar systems based on the SSV's appearance in certain lighting
conditions which may be challenging for camera systems. We believe the
SSV appears to be a real vehicle to most
[[Page 68617]]
current AEB systems, regardless of what sensor or set of sensors the
systems uses, and that the SSV elicits AEB responses representative of
how the systems will perform in real world driving situations. The
ability of the SSV to withstand SV-to-POV impacts appears to be
adequate if the subject vehicles being evaluated produces even minimal
speed reductions to mitigate them. We continue to evaluate SSV
performance and will consider improvements.
Some commenters indicated NHTSA should increase the padding to the
SSV to reduce the likelihood of damage to the test equipment or to the
SV during an SV-to-POV impact. When designing the SSV, we attempted to
balance realism, strikeability, and durability. The body structure and
frame of the SSV are constructed from carbon fiber to make them stiff
(so that the shape remains constant like a real car), strong, and light
weight. To enable SV-to-POV impacts, the SSV frame has design elements
to accommodate severe impact forces and accelerations and an 8 in (20.3
cm) deep foam bumper to attenuate the initial impact pulse. We are
concerned that simply adding more padding to the rear of the SSV will
reduce its realistic appearance, and potentially affect AEB system
performance. Therefore, to address the potential need for additional
SSV strikeability, the agency is presently considering an option to
work with individual vehicle manufacturers to add strategically-placed
foam to the SV front bumper to supplement the foam installed on the
rear of the SSV. At this time, no changes to the appearance of the SSV
are planned. Since temporary padding added to the subject vehicle does
not alter that characteristics of the SSV nor affect the distance of
the SSV to the vehicle sensors, we will not be adjust the zeroing
procedure in the test procedure to compensate for this one-time padding
addition.
With regards to sensor bias, the SSV has been designed to be as
realistic as possible to all known sensors used by AEB systems. While
it is true that the SSV has a strong radar presence, use of the white
body color and numerous high-contrast features (e.g., actual tail
lights and bumper reflectors, simulated license plate, dark rear
window, etc.) was intended to make it as apparent as possible to camera
and lidar-based systems as well. Aside from inclement weather and
driving into the sun, conditions explicitly disallowed by NHTSA's CIB
and DBS test procedures, sensor limitations capable of adversely
affecting the real-world detection, classification, and response of a
SV to actual vehicles during real-world driving may also affect the
ability of the SV to properly respond to the SSV. The agency considers
this an AEB system limitation, not an SSV flaw.
F. Other Issues
1. Non-Ideal Conditions--Exclude Away From Sun as Well
NHTSA's CIB and DBS test procedures both include a set of
environmental restrictions designed to ensure that proper system
functionality is realized during a vehicle's evaluation. One such
restriction prohibits the SV and POV from being oriented into the sun
when it is oriented 15 degrees or less from horizontal, since this can
cause inoperability due to ``washout'' (temporary sensor blindness) in
camera-based systems.
DENSO commented that, in addition to prohibiting testing with the
test vehicles oriented toward the sun when the sun is at a very low
angle (15 degrees or less from horizontal) to avoid camera ``washout''
or system inoperability, the test procedures should also prohibit
testing with vehicles oriented away from the sun (with the sun at low
angle) which would harmonize this issue with Euro NCAP test procedure.
MEMA agreed that wash out conditions experienced in low sun angle
conditions for SV and POV oriented toward the sun may also occur when
they are oriented away from the sun.
To date, the agency's testing does not indicate that a low sun
angle from the rear will adversely affect AEB system performance.
Moreover, one of the agency's testing contractors indicates that
restricting the sun angle behind as well as in front of the test
vehicle will significantly reduce the hours per day that testing may be
performed. If our ongoing experience suggests that this is a problem
for vehicles equipped with a particular sensor or sensor set, we will
consider making adjustments.
2. Multiple Safety Systems
TRW inquired as to how safety systems other than AEB systems on a
test vehicle would be configured during AEB testing. The company asked
whether there would be provisions in the test procedure for turning off
certain safety features in order to make the testing repeatable. It
gave as an example some pre-crash systems that may be activated based
on these tests.
Due to the complexity and variance of vehicle designs the agency
will deal with system conflicts on a one-on-one basis. The agency does
not specify or recommend that vehicle manufacturers design and include
cut-off provisions for the sole purpose of performing AEB tests.
3. Motorcycles
The AMA said that all AEB systems included in NCAP should be able
to detect and register a motorcycle. If not, vehicle operators may
become dependent on these new technologies and cause a crash, because
the system did not detect and identify a smaller vehicle, the
organization said.
AEB systems, while relatively sophisticated and available in the
American new vehicle marketplace, are still nonetheless in the early
stages of their development. Some may be able to detect motorcycles.
Some may not be able to do so. Eventually, the sensitivity of these
systems may increase to the point where detecting a motorcycle is
commonplace among systems.
The agency believes it would be benefit to highway safety move
forward with this program at this time, even though it does not include
motorcycle detection. By including AEB systems among the advanced crash
avoidance technologies it recommends to consumers in NCAP, the agency
expects more and more manufacturers to equip more and more new vehicles
with these systems. As a result, many rear-end crashes and the
resulting injuries and deaths will be avoided. The agency believes it
will be beneficial to take this step even if the systems involved are
not as capable of recognizing motorcycles today.
We also do not have reason to believe that AEB systems are the type
of technology likely to encourage over-reliance by drivers. DBS is
activated based on driver braking input, and CIB is activated when for
one reason or another, the driver has not begun to apply the brake. We
do not think that in either scenario the driver is likely to drive
differently under the assumption that the AEB system will perform the
driver's task.
The agency will continue to follow the ongoing development and
enhancement of AEB systems and look for opportunities to encourage the
development and deployment of systems that detect motorcycles.
4. How To Account for CIB/DBS Interaction
Honda asked how the interrelationship between CIB and DBS should be
treated, in situations in which CIB activates before the driver applies
the brakes and DBS never activates.
The brake applications used for DBS evaluations are activated at a
specific point in time prior to an imminent
[[Page 68618]]
collision with a lead vehicle (time-to-collision) regardless of whether
CIB has been activated or not. If CIB activates before DBS, the initial
test speed and, thus, the severity of the test would effectively be
reduced.
TRW observed that one potential future trend to watch is that as
industry confidence and capability to provide CIB functionality
increases and the amount of vehicle deceleration is allowed to increase
and be applied earlier in the process, the need for DBS as a separate
feature may diminish. The potential goal of DBS testing would become
one of proving a driver intervention during an AEB event does not
detract from the event's outcome, TRW said.
At this time, the agency is aware that many light vehicle DBS
systems supply higher levels of braking at earlier activation times for
the supplemental brake input compared to the automatic braking of CIB
systems. Based on this understanding of current system design, our NCAP
AEB test criteria for DBS evaluates crash avoidance resulting from
higher levels of deceleration, whereas our CIB test criteria evaluates
crash mitigation (with the exception of the CIB lead vehicle moving SV:
25 mph/POV: 10 mph (SV:40 km/h/POV: 16 km/h) scenario, for which crash
avoidance is required). NHTSA will keep the speed reduction evaluation
criteria as planned for the CIB and DBS tests.
Unless the agency uncovers a reason to be concerned about how the
performance metrics of a test protocol may affect system performance in
vehicles equipped with both CIB and DBS, the agency will recognize an
AEB equipped vehicle as long as it passes the criteria of a given
protocol, whether that occurs as a result of the activation of the
particular system or a combination of systems.
5. Issues Beyond the Scope of This Notice
Some commenters raised topics outside the scope of the notice, and
they will not be addressed here.
These include: A suggested two-stage approach to adding
technologies to NCAP, a suggested minimum AEB performance regulation
that would function in concert with NCAP, conflicts between rating
systems that could cause consumer confusion, other technologies that
should be added to NCAP in the future, and a call for flashing brake
lights to alert trailing drivers that an AEB system has been activated.
Other topics raised may be addressed as the agency's experience
with AEB systems expands over time. These topics include: Using
different equipment, including a different surrogate vehicle; a call to
study the interaction of the proposed CIB/DBS systems with tests for
FMVSS Nos. 208 and 214 to assess whether such features should be
enabled during testing and what the effect may be; a suggestion that
the agency should consider the role electronic data recorders (EDRs)
may play in assessing AEB false positive field performance; and concern
as to how safety systems on a test vehicle other than AEB systems would
be dealt with during AEB testing, such as some pre-crash systems that
may be activated based on these tests.
A suggestion was made that the agency should consider the potential
interactions of AEB systems with vehicle-to-vehicle (V2V)
communications technology, both in how AEB tests might be performed and
what the performance specifications for those tests should be. The
agency is monitoring the interaction of these capabilities.
V. Conclusion
For all the reasons stated above, we believe that it is appropriate
to update NCAP to include crash imminent braking and dynamic brake
support systems as Recommended Advanced Technologies.
Starting with Model Year 2018 vehicles, we will include AEB systems
as a recommended technology and test such systems.
(Authority: 49 U.S.C. 32302, 30111, 30115, 30117, 30166, and 30168,
and Pub. L. 106-414, 114 Stat. 1800; delegation of authority at 49
CFR 1.95.)
Issued in Washington, DC, on: October 21, 2015.
Under authority delegated in 49 CFR 1.95.
Mark R. Rosekind,
Administrator.
[FR Doc. 2015-28052 Filed 11-4-15; 8:45 am]
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