Lamps, Reflective Devices and Associated Equipment; Denial of Petition for Rulemaking |
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Topics: National Highway Traffic Safety Administration
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Barry Felrice
Federal Register
August 3, 1994
[Federal Register: August 3, 1994]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 571
Lamps, Reflective Devices and Associated Equipment; Denial of
Petition for Rulemaking
AGENCY: National Highway Traffic Safety Administration (NHTSA), DOT.
ACTION: Denial of petition for rulemaking.
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SUMMARY: This notice denies a petition for rulemaking by Baran Advanced
Technologies, Ltd., to amend Federal Motor Vehicle Safety Standard No.
108 to allow the abrupt release of the accelerator pedal to operate
stop lamps. The reason for the denial is the importance of retaining
the existing requirement for activating the stop lamps only through
application of the brake pedal in order to avoid confusion.
FOR FURTHER INFORMATION CONTACT: Patrick Boyd, Office of Vehicle Safety
Standards, NHTSA (202-366-6346).
SUPPLEMENTARY INFORMATION: Baran Advanced Technologies, Ltd. of Israel
manufactures a device called ``Red Alert'' which is intended to
activate the stop lamps during emergency braking before the brake pedal
is applied, thereby providing an earlier warning for following
vehicles. The device senses the rate at which the accelerator pedal
returns to its upper stop after being released. It activates the stop
lamps for one second if the accelerator pedal reaches its upper stop at
greater than a certain predetermined rate. Its operation is based on
the assumption that any rapid release of the accelerator pedal is the
beginning of an emergency braking maneuver, and thus will be
immediately followed by application of the brake pedal. Application of
the brake pedal continues to activate the stop lamp in the usual way.
If the brake pedal is depressed within one second of the release of the
accelerator, the brake light will remain on at the end of the initial
one second period of activation and thus provide a steady signal.
Standard No. 108 requires that stop lamps ``shall be activated upon
application of the service brakes.'' That requirement has been
interpreted to mean that the stop lamps are to be activated only upon
activation of the service brakes. Some years ago, Baran's competitor in
the Israeli market, ATAT, sought an interpretation of Standard No. 108
that would allow the aftermarket installation of its similar Advanced
Brake Light Device (ABLD) in the U.S. In a letter of January 25, 1990,
to Larry Snowhite, Esq., the agency concluded that accelerator release
activation by an aftermarket device such as the ABLD would render the
stop lamps partially inoperative within the meaning of the prohibition
of 15 U.S.C. 1397(a)(2)(A). Said NHTSA:
The heart of our concern is that while the standard requires the
stop lamp to operate in only one particular circumstance, the ABLD
causes the stop lamp to operate at an earlier time when the lamp is
supposed to be unlighted. Further, the ABLD's activation of the stop
lamp indicates only that the operator has released the accelerator.
It does not necessarily follow that the brake pedal will be applied.
Under this fact situation, the stop lamps fulfill a purpose other
than for which they are installed. This can only create the
potential for confusion and dilution of the effectiveness of the
stop signal. For the reasons stated above, we have concluded that
installation of the ABLD in the aftermarket would render the stop
lamps partially inoperative.
Baran's ``Red Alert'' and ATAT's ABLD operate under the same
fundamental principle of measuring the accelerator pedal return rate to
anticipate emergency braking. ATAT did not report its threshold rate
for accelerator pedal release. However, the fact that its false alarm
rate is similar to that of the Baran system suggests that the
activation of both systems is based on a similar threshold rate of
accelerator release. These rates are discussed later in the notice.
NHTSA has examined Baran's petition in an effort to balance
possible safety benefits of the device against the possible safety
disbenefits of signal confusion.
The first issue is whether the petitioner can demonstrate that its
device is likely to lessen the number of accidents. Baran estimates
large reductions in rear-end accidents using figures from a paper by
Enke ``Possibilities for Improving Safety Within the Driver-Vehicle
Environment Control Loop'' and from a NHTSA report on Intelligent
Vehicle Highway System (IVHS) countermeasures to rear end accidents
(DOT HS 807 995). Enke's paper estimates that the impact speed of 25
percent of rear end accidents is no more than 10 km/hr (9 ft/sec) and
that the amount of distance traveled at the assumed initial speed for
0.25 second equals the distance required to stop from the impact speed.
Baran claims that ``based on Enke's analysis, providing a driver with
an additional .25 seconds of warning of an impending stop by the
leading driver could result in a 25 to 30 percent reduction in all
rear-end accidents.''
NHTSA disputes this conclusion. Enke's analysis presumes that the
following driver is attentive to the very first glimmer of a stop
signal from the car ahead and that (s)he reacts immediately even though
a speed differential has not yet occurred. It also presumes that the
lead driver decelerates so rapidly that the following driver cannot
``outbrake'' the lead driver and that the initial distance between them
is less than following driver's reaction time multiplied by the initial
speed. NHTSA views these presumptions as unrealistic.
Further, NHTSA's IVHS report characterizes a rear-end crash as
``largely a dry/straight road phenomenon associated with driver
inattention.'' It found the lead vehicle stopped (LVS) in 75 percent of
rear-end crashes, which
Typically do not involve simply a ``too-slow'' reaction of the
following driver to a sudden crash threat. In the most common
scenario, the lead vehicle is stopped for an extended interval
(i.e., 2-6 seconds) before it is struck by the following vehicle.
There is adequate time to provide a warning to the following driver
and for the driver to avoid the crash. Vehicles involved in this
crash subtype should not be viewed as a locked pair where one
vehicle is following the other at a specified distance. Instead, the
following vehicle is closing on a stationary object. The initial gap
distance between the vehicles is often several hundred feet or more.
No cases were identified where a lead vehicle decelerated rapidly
and then was hit by a closely following vehicle immediately after
coming to a stop.
It is difficult to see how a 0.25 second advance stop lamp warning
would be of any use in the 75 percent of rear-end accidents in the LVS
category when prolonged driver inattention appears to be a near
universal cause.
The report characterized the remaining 25 percent of rear-end
accidents, those in which the lead vehicle was moving (LVM) at impact,
as follows:
In contrast, the LVM crash subtype may involve driver reaction
time following a sudden crash threat as a critical factor. Vehicles
involved in this circumstance are often ``locked pairs'' with one
vehicle following the other. However, gaps or following distances
can range from a few lengths to very substantial distances even in
this subtype. Not all LVM crashes are precipitated by rapid
deceleration of the lead vehicle. Many involve slow decelerations
(e.g., typical slowing before a turn) or simply a speed differential
between the lead and following vehicles.
This also indicates that driver inattentiveness is critical in LVM
crashes. It is hard to accept that a 0.25 second advance in stop lamp
activation would be of value to an inattentive following driver. NHTSA
accepts the IVHS report as an accurate reflection of the conditions
under which rear-end collisions happen, and has concluded that Red
Alert would not provide an adequate warning to avoid these collisions
in virtually all the circumstances under which they occur.
Nevertheless, a manufacturer should not be precluded from offering
its product, even if safety benefits cannot be demonstrated, unless
there are potential safety disbenefits created by the product. The
agency objected to ATAT's ABLD because it was not an unambiguous signal
of brake application. NHTSA believed that such devices created the
potential for confusion and dilution of the effectiveness of the stop
signal. It pointed out that the activation of the stop signal under the
requested circumstances only signified that the accelerator had been
released. It did not necessarily follow that the brakes would be
applied. The brakes were not applied 28 percent of time that the ABLD
activated in a test report submitted by its proponent, ATAT. Similarly,
the brakes were not applied 23 percent of the time the ``Red Alert''
activated in a test report submitted as part of Baran's petition.
However, both devices activated the stop lamps far less frequently
than did the ordinary brake switch activated by depression of the brake
pedal. During their respective tests, the ABLD activated the stop
signal about 3 percent as frequently as the ordinary brake switch did.
``Red Alert'' activated the signal about 1.2 percent as frequently.
Both tests compared the number of false alarms to the number of
ordinary stop signal activations of one second or less. False alarms of
``Red Alert'' were about 2.4 percent as frequent as short brake
applications, and false alarms of the ATAT device were reported as less
than 10 percent as frequent as short brake applications. The conditions
under which the two devices were tested differed greatly. ATAT used a
special test course, three test vehicles and a limited number of test
subjects who knew that some undisclosed part of their driving behavior
was being evaluated. Baran installed ``Red Alert'' on six communal car
pool vehicles that were operated for a period of months in ordinary
traffic by various drivers who had no knowledge that their behavior was
being measured. Given the large variations in activation and false
alarm rates between test vehicles within each test and the differences
in test conditions between the ABLD and ``Red Alert'' tests, there is
no reason to believe that the two devices vary significantly in
activation rate and false alarm performance.
The activation rate observed in both tests seems to be too high for
true emergency braking actions, as neither test documented an actual
incident of emergency braking. ATAT did not report either observing
emergency maneuvers or questioning its subjects regarding such
instances, but it did measure the foot movement times when the
accelerator control activated the stop lamp. A range between 0.23 and
0.77 second was observed. When ATAT's subjects were asked to perform
fast accelerator to brake movements, the 5th and 95th percentile times
were 0.10 and 0.28 second respectively. It appears that very few of the
activations in ATAT's test of an accelerator controlled stop lamp were
rapid enough to indicate an emergency. Baran did not report
measurements of foot movement times, but it assumed that ``Red Alert''
activations were equivalent to instances of emergency braking. ``Red
Alert'' was characterized as providing an advance warning of 0.35
second which falls outside of ATAT's rapid foot movement range.
Both manufacturers argued that the false alarms were insignificant
because they were few in comparison to the quite large number of brake
applications of less than one second. Baran also argued that the short
brake applications themselves had little significance because the
duration of brake effort would be further reduced by the time consumed
to build up pressure and to release the brake pedal within one second.
Baran pointed out that a short brake application may represent only a
release of cruise control, a state of preparedness or a warning to
other drivers. While these facts tend to diminish the importance of the
systematic false alarms, they also demonstrate why following drivers
are unlikely to act at the instant of the stop lamp illumination in the
absence of closing speed or some other cue. All the test experience
reported for accelerator controlled stop lamps involved leading and
following drivers who were unaware of the use of the device. But this
device facilitates intentional false alarms as well as systemic
occurrences. Its widespread use would raise suspicions of intentional
false alarms on the part of drivers in following vehicles. Intentional
false alarms can and will occur, sending a misleading signal to the
driver behind.
To sum up, the idea that a slightly anticipatory brake lamp will
prevent large numbers of rear-end collisions is intuitively attractive.
However, it ignores the fact that lack of driver attention is the root
cause of rear-end accidents. It is unlikely than an extra quarter
second of brake light activation would cure or offset the
inattentiveness of a following driver.
The agency concludes that the potential safety benefits are
minimal, but it will consider the results of the Israeli Highway Safety
Administration's trial of accelerator-controlled stop lamps when they
are available. While Baran's data indicate that the absolute numbers of
systematic false alarms may be small on average, a perception by
following drivers that the brake signal allowed false alarms, whether
or not intentional, might dilute the currently unambiguous message of
the stop signal. The agency previously found that ATAT's device would
render the stop lamp partially inoperative as a result of the same loss
of unambiguous operation. There are no fundamental differences between
the systems to cause the agency to change its determination or even to
allow the agency to distinguish between them in a regulation.
Accordingly, NHTSA has conducted and concluded a technical review
of the petition, and has determined that there is not a reasonable
possibility that the amendment requested would be issued at the
conclusion of a rulemaking proceeding. Accordingly, the petition by
Baran Advanced Technologies, Ltd., for rulemaking to amend Standard No.
108 is denied.
Authority: 49 U.S.C. 30103; delegation of authority at 49 CFR
1.50 and 501.8.
Issued on: July 28, 1994.
Barry Felrice,
Associate Administrator for Rulemaking.
[FR Doc. 94-18802 Filed 8-2-94; 8:45 am]
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