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15 The dramatic failure of US safety policy
This html version contains only the text (no figures, tables equations, or summary and conclusions). To check printed book appearance see pdf version of Chapter 1 or pdf version of Chapter 16.
Introduction
This chapter is intimately related
to Chapter 12 on airbags. This is not because airbags, as
devices, are central to traffic safety. In 2003 they reduced
fatality risk by 10% for 47% of road users, thus reducing US
total fatalities by almost 5%. Such a reduction, without
affecting anything else, would be important, even if much
less important than the driver factors discussed in Chapters
13 and 14.
The role of the airbag in US safety
policy was not so much as a device, but as an icon for a
safety philosophy that precipitated a national disaster.
Below we use simple analyses of readily accessible public
data to document the extent of the disaster, and then
discuss the background that contributed to it.
The US compared to other countries
Prior to the mid 1960s the US
had the safest traffic in the world, whether measured by
deaths per registered vehicle, or deaths for the same
distance of travel. A series of tabulated rates for the US
and 11 other major industrialized countries for the years up
to 1978 appeared under the headline U.S. the Safest Place
for Driving. (p 52) US rates were substantially lower than
those in any of the other countries listed.
By 2002, in terms of deaths per
registered vehicle, the US had dropped from first place into
sixteenth place, behind Australia, Austria, Canada, Denmark,
Finland, Germany, Great Britain, Iceland, Japan, Luxembourg,
the Netherlands, New Zealand, Norway, Sweden, and
Switzerland.
Comparing rates in 2002 to rates in 1979
The decline in US safety relative to other countries
is explored below by comparing changes in specific US
fatality rates with the changes in the same rates in other
countries. Three traffic fatality rates are examined:
1. Fatalities per year.
2. Fatalities per thousand registered vehicles (the vehicle
rate).
3. Fatalities per billion km of vehicle travel (the distance
rate).
Three countries, Great Britain,
Canada, and Australia, are selected for the comparisons.
These three countries are chosen because they have much in
common with the US in terms of language, beliefs, and
traditions. Performance is compared is over the 23-year
period from 1979 to 2002. It was in the late 1970s/early
1980s that the safety policies of the US and other countries
began to diverge. The results are not all that different if
the initial and final times were a few years earlier or
later, or if some different comparison countries were
chosen.
Fatalities per year comparisons. Figure 15-1 shows
the change in the simplest measure of safety performance,
total traffic deaths per year. While fatalities in the 23
year period declined in the US by 16.2%, declines of 46.0%,
49.9%, and 51.1% occurred in Britain, Canada, and Australia
(Table 15-1). In the prior 1960-1978 period the comparison
countries did not systematically outperform the US. On the
contrary, fatalities in Canada and Australia increased by
65% and 50% (compared to a 38% increase in the US), but in
GB decreased by 2%.
The number of traffic deaths that
would have occurred in the US in 2002 if US fatalities had
declined by the same percents as in the comparison countries
from 1979-2002 are shown in Table 15-2. If the US total had
declined by 46.0%, as it did in Great Britain, then US
fatalities in 2002 would have been 27,598 instead of the
42,815 that occurred. (All derivations are based on
calculations including more decimal places than shown in
tables). By matching the British decline, 15,217 fewer
Americans would have been killed in 2002. The corresponding
fatality reductions for matching Canadian and Australian
performance are 17,229 and 17,837.
Figure 15-1. Traffic fatalities per year in the US and in
three comparison countries.
Table 15-2. Estimated number of fatalities that would have occurred in the US in 2002 if the US had achieved the same percent decline in fatalities per year between 1979 and 2002 as the comparison countries.
Fatalities per registered vehicle comparisons.
Because of the disparate numbers of vehicles in different
countries, raw fatalities can be compared effectively only
by renormalizing in some way as in Fig. 15-1. However, rates
such as fatalities per thousand registered vehicles (the
vehicle rate) can be plotted without the need to select a
reference year, as shown in Fig. 15-2. Prior to the late
1970s the comparison countries, in common with all
countries, had rates higher than the US. The change in time
from a higher to a lower rate than for the US is illustrated
additionally for Sweden in Fig 3-6, p. 41. The US rate shows
no indication of a drop in response to any major vehicle
safety legislation, such as the National Traffic and Motor
Vehicle Safety Act of 1966 that required all vehicles
manufactured in 1968 or later to satisfy a number of Federal
Motor Vehicle Safety Standards (FMVSS). The only notable
downward spike, in 1974, is unrelated to vehicles, but
reflects various changes stimulated by the 1973 oil embargo,
including driver behavior changes, especially speed
reductions in response to changes in speed limits (Fig. 9-3,
p. 213).
Table 15-3 shows the changes in the
vehicle rate from 1979 to 2002 for the US and the comparison
countries. The US decline of 46.2% in a 23 year period might
seem impressive, but it corresponds to a compound decline of
only 2.7% per year. This is less than the average 3.1% from
1900-2002, and still less than the 3.2% from 1900-1978. Thus
US safety policy in the 1979-2002 period did not lead to
declines as large as occurred in earlier decades.
Table 15-3. The percent reduction in the vehicle rate
(number of fatalities per thousand registered vehicles)
between 1979 and 2002 in the US and in three comparison
countries.
change in rate, 1979-2002 -46.2% -67.1% -63.5% -71.9%
While the US vehicle rate declined
by 46.2%, the rates in Britain, Canada, and Australia
declined by 67.1%, 63.5%, and 71.9%. If the US rate had
declined by the same 67.1% it did in Britain, then in 2002
the US rate would have been 0.354 (1-0.671) = 0.116
fatalities per thousand vehicles, instead of the 0.190 rate
observed. Applying the 0.116 rate to the 224,974 thousand
vehicles in the US in 2002 would have led to 26,210
fatalities, 16,606 fewer than the 42,815 observed. The US
fatality reductions from matching the declines in the
Canadian and Australian vehicle rates are 13,718 and 20,429.
Fatalities for the same travel distance comparisons. The
best estimates of distance of vehicle travel are for Great
Britain, based on observations at fifty sites supported by
the Department of Transport. Reliable estimates over a long
period are not available for most countries, so the
comparison will be confined to Great Britain. Because we
compare how rates change in time, the fact that vehicles in
the US travel greater distances per year than in other
countries is not important provided trends in the distance
of travel per vehicle are not markedly different between the
countries compared, which they are not. Greater travel in
the US leads to lower distance rates every year. While the
US dropped from number one ranking to number 16 in deaths
per vehicle, for deaths for the same travel distance it
dropped from number one ranking to number 10, behind
Australia, Canada, Denmark, Finland, Great Britain, the
Netherlands, Norway, Sweden, and Switzerland.2
Figure 15-3 shows that while the
distance rate in Britain was (as in all countries)
previously higher than in the US, in 2002 it was lower.
Table 15-4 shows the 1979 to 2002 comparison for the
distance rate parallel to the Table 15-3 for the vehicle
rate. If the US distance rate had declined by the
same 71.3% that occurred in Britain, US fatalities in 2002
would have
been 4,553.8 20.8 (1-0.713) = 27,145 instead of the 42,815
observed. By matching the British decline, 15,670 fewer
Americans would have been killed
in 2002.
Average comparisons 2002 versus 1979. I have
presented results like the above in publications , and in
many oral presentations, in most cases for just one of the
rates due to limited space or time. One of the most common
reactions from surprised readers and audiences is,
"What would the result have been if instead of (say)
the vehicle rate, you had used the distance rate?"
Anticipating such questions, all three rates are given,
leading to the values summarized in Table 15-5.
Averaging over the rates available
for the comparison countries gives the results that:
If US matched Great Britain 15,831 fewer US fatalities in
2002.
If US matched Canada 15,474 fewer US fatalities in 2002.
If US matched Australia 19,133 fewer US fatalities in 2002.
Table 15-4. The percent reduction in the number of
fatalities per billion km of vehicle travel between 1979 and
2002 in the US and in GB.
The average of all seven estimates
in Table 15-5 is 16,672. This leads to the conclusion that
if the US had matched the changes in safety achieved in the
comparison countries from 1979-2002, instead of 42,815
fatalities in 2002, the US would have had 26,143.
Fatality differences accumulated over the 1979-2002
period
All the above has focused on
comparing differences between 2002 and the reference year
1979. Table 15-6 shows the calculation of the vehicle rate
for Great Britain for every year between 1979 and 2002. The
2002 data are the same as in Table 15-3. The conclusion from
this table is that if the US vehicle fatality rate had
declined each year since 1979 by the same percent as it did
in Britain, 177,593 fewer Americans would have been killed
in the 23-year period. Details of this and other
calculations for the other values in Table 15-7 are in Excel
files on the Internet. The variation, from 163,007 to
266,686 is not surprising as the cumulative values reflect
changes occurring at different times in the different
comparison countries, as is apparent in Figs 15-1 and 15-2.
Averaging over the rates available
for the comparison countries gives the results that:
If US matched Great Britain 163,007 fewer US fatalities
1979-2002.
If US matched Canada 247,972 fewer US fatalities 1979-2002.
If US matched Australia 207,854 fewer US fatalities
1979-2002.
The average of the 7 values in Table 15-6 is 214,286. The
leads to the conclusion that because US safety performance
failed to match that in the comparison countries in the
23-year period from 1979 to 2002, about 200,000 additional
Americans died in traffic crashes.
Table 15-7. Estimates of the number of fewer American
deaths in the period 1979 to 2002 if changes in US rates had
matched changes in rates of comparison countries. The
average of the seven values is 214,286.
rate reduction in 2002 traffic deaths if US had matched
1979-2002 percent changes in:
GB Canada Australia
per year 163,007 247,972 207,854
per thousand vehicles (vehicle rate) 177,593 221,413 266,686
per billion km (distance rate) 215,480 - -
Search for an explanation
While 200,000 additional US
fatalities were shown by straightforward analyses of
publicly available data, it is not possible to explain why
this occurred by a similarly simple analysis. Yet there must
be an explanation, even if it cannot be formulated in simple
multiplicative factors. The explanation below reflects my
judgmental conclusions based on experience and involvement
in many traffic safety issues in many countries spread over
a number of decades. I believe that the interpretation owes
much to my perspective from growing to adulthood outside the
US before later becoming a US citizen.
As the difference between US performance and that in other
countries is so great, it must flow from large basic
differences between the US and other countries. I believe
that the key is the uniquely powerful role litigation has
come to play in the US, producing the following interlaced
effects:
1. US safety policy priorities have been ordered almost
perfectly opposite to where technical knowledge shows
benefits are greatest (as represented in Fig. 13-4, p. 339).
2. This happened because US policy was defined and led by
ideologically driven lawyers lacking knowledge or interest
in technical matters.
3. Such leadership emerged because of the uniquely powerful
influence of law on all aspects of US society, which is
without parallel in any other country.
Comparison countries are normal
When I have mentioned safety
differences between the US and comparison countries, the
most common American response is to ask, "What do the
comparison countries do that is so special?" It is
natural to assume that you are normal, and all who differ
from you are abnormal. Those asking the question are
generally surprised by my answer that the comparison
countries did nothing particularly special. They made
mistakes, adopted flawed policies, etc. All their laws are
passed by democratic legislative bodies answerable to
electorates they must not displease. The performance of the
selected countries is not particularly different from that
of the Netherlands, Sweden, Finland, or Japan. The
comparison countries do not, and nor should they, celebrate
any traffic safety triumph. Over a thousand deaths per year
to healthy young citizens in each country is no cause for
celebration. Indeed, all the best performing countries
acknowledge traffic crashes as a major public health problem
requiring urgent attention to a much greater extent than
occurs in the US.
It is the US that is aberrant
One of the most remarkable features
of the extraordinary failure of US safety policy is that it
is one of the nation's best-kept secrets. Those primarily
responsible for so spectacular a failure receive only
praise, and lots of it, from their long-time supporters and
allies, the mass media. Even the US injury control
establishment thinks all is well. Two injury-control
academics (with law degrees) disagreed with my editorial in
the American Journal of Public Health. They wrote that the
US "reduction in the risk of fatal motor vehicle crash
is one of the major success stories of public health and
injury prevention." They supported this statement by
noting a more than 70% decline in the distance rate in the
35 years from 1966 to 2001, and attributed the
"success" to vehicle regulation and litigation.
They were unaware that a larger decline occurred in the
first 35 years (1921-1956) for which data were available,
and in which the factors they claimed produced the declines
were not present. More particularly, they were unaware that
in the same 1966 to 2001 period they choose, the British
rate declined by 84%, and that if US declines had matched
those in Britain during this period, more than 300,000 fewer
Americans would have been killed. The dramatic failure of US
safety policy shows in any period after the mid 1960s.
Irrelevance of numbers and technical knowledge
A dramatic change in the US approach to
safety occurred when activist lawyer Ralph Nader convinced
the US media, government, and public that the problem was
unsafe and defective vehicles. Even if claims in his 1965
book Unsafe at Any Speed had merit, their effect was to
focus attention on a dozen or so deaths occurring over a
number of years, while ignoring the 50,000 deaths occurring
annually at that time.
A picture is worth a thousand words
The photograph in Fig. 15-4 shows Ralph
Nader demonstrating an airbag simulator "safely"
deploying into the face of an unbelted three-year-old girl.
The photograph was taken on 5 July 1977 at a Washington, DC
press conference convened to support airbags. By 1977 the
technical community had been long aware that deploying
airbags posed risks to occupants, particularly children. A
study titled "Airbag effects on the out-of-position
child" was presented at a Society of Automotive
Engineers meeting in Detroit in May 1972, by which time the
published paper was already available. The study, performed
in the US, used child dummies and baboons of size and weight
similar to children to investigate if deploying airbags
posed injury threats to children. It found that they did. A
Swedish study titled "Possible effects of air bag
inflation on a standing child" was presented at
technical meetings in Canada and France in 1974, and
documented in the proceedings of these meetings. , The study
used pigs to simulate what would happen to an
out-of-position child who leaned against the air bag as it
deployed. In eight of the twenty-four trials the airbag
deployment killed the pig.
The individual exercising the greatest influence on US
safety policy was untrained, uninformed, uninvolved, and
uninterested in technical matters. Press conferences, not
technical meetings, were his milieu. The individuals
influencing safety policy in other countries were mostly
technically trained, and attended technical meetings such as
those at which the information on harm from airbags was
communicated.
Quantitative information now
augments the early 1970s qualitative understanding that
airbags posed threats to children. Airbags increase fatality
risk to unbelted children in front seats by 84%. Even if the
child is belted, the airbag still increases risk by 31%.
NHTSA reports that (by July 2003) 144 children had been
killed by airbag deployments in crashes that would not
otherwise have caused major, or any, harm. An important
contributor to the failure of US safety policy is the
advocacy role of the media. Reports of children killed by
airbags rarely mentioned Ralph Nader or his disciples. Yet
his name is mentioned often in the media to praise his role
in making the US safer!
The airbag mandate
Nader's protégé, lawyer Joan
Claybrook, had an even greater influence on US safety policy
than her mentor. Claybrook became the senior safety official
in the US when President Carter appointed her Administrator
of the National Highway Traffic Safety Administration (NHTSA)
in 1977. A NHTSA official is quoted as saying, "Joan
came to NHTSA with a mission and that mission was air
bags." (p 109) More specifically, the mission was an
airbag mandate, a government requirement that airbags be
installed in vehicles. Technical information, such as the
effectiveness of airbags, never impeded that goal.
Earliest quantitative estimate of airbag effectiveness
The earliest quantitative estimate
of airbag effectiveness was reported in a study by General
Motors published in 1973, before airbag field data were
available. A panel of four expert engineers examined details
of fatal crashes in which 706 occupants died. Using crash
reports, medical and/or autopsy reports, photographs, and
other relevant information, the panel discussed the injury
mechanisms for each fatally injured occupant, and arrived at
a judgment about whether an airbag would have prevented the
fatality. The study concluded that airbags would have
prevented 18% of the fatalities to front-seat occupants.
The NHTSA effectiveness values used to justify the
mandate
The airbag effectiveness numbers
used to justify the mandate were published by NHTSA in 1977
in the Federal Register, the daily compilation of federal
regulations, legal notices, etc. The relevant table is
reproduced as Fig. 15-5. (Table I,p 34297) Airbags were
claimed to reduce AIS 4 to AIS 6 injuries by 40%. This
injury range includes nearly all fatalities, so airbags are
claimed to reduce fatality risk by 40%. The claims are for
unbelted occupants.
Figure 15-5. NHTSA's 1977 estimates of effectiveness used to justify mandating airbags (called air cushions in the table). Reproduction of Table I on page 34297 of Ref. 20.
So great was the belief in airbags that part of the cost of installing them was to be offset by the cost savings due to not installing safety belts (Fig. 12-6).20(Table III,p 34299) Because US airbag standards are still defined for unbelted dummies, US airbags must inflate more rapidly than those of other countries, whose standards are for belted occupants. This contributes to the risk of airbag-caused injuries being so much greater in the US.
Figure 15-6. In support of requiring airbags, NHTSA
documents that the cost would be partially offset by savings
from not having to install safety belts (4th row, negative
costs labeled Removed Belts). Reproduction of Table III on
page 34299 of Ref. 20, where it is cited as FR Doc.77-19137.
Filed 6-30-77; 1:00 pm.
Key estimates of airbag
effectiveness in reducing (mainly non-fatal) injury risks,
in chronological order of their publication, are shown in
Table 15-8 (more extensive lists for all injury levels are
presented in Ref. ). The second entry in Table 15-8 showing
an approximate 9% effectiveness for AIS>3 injury risk is
based on a GM study of data from the fleet of 10,000 GM
airbag-equipped cars sold in the mid 1970s. While sample
sizes were small, the evidence from this fleet (known well
before the 1 February 1978 publication date of the paper22)
was more than sufficient to reject as implausible the NHTSA
estimates. The other values in Table 15-8 were discussed in
Chapter 12.
Table 15-8. Key estimates of the effectiveness of airbags
in reducing injury risk.
Key estimates of the
effectiveness of airbags in reducing fatality risk are
listed in Table 15-9. As late as 1984, the 40% fatality
reducing effectiveness figure had not been totally abandoned
by NHTSA, but it was then included
just as the upper limit of a wide (20-40)% range. Although
NHTSA
has benefited from an entirely different type of leadership
since 1981, it is always difficult for institutions to
repudiate prior positions, no matter how indefensible. As
distinct from the 1977 estimates published to support policy
goals, NHTSA's technical staff applied technically sound
methods to FARS data, and estimated effectiveness to be
substantially lower than the 18% estimate in the 1973 GM
study. The method of the GM study systematically biases
effectiveness estimates upwards. All the subjects were dead,
so only factors that could have reduced the probability of
death were considered.
No information was considered about occupants who had not
been killed. Yet if all of these had airbags, some would
have been killed by airbags. Not estimating such effects
would bias the estimate upwards, and contribute to
the 18% estimate being higher than the current 12% estimate
for unbelted occupants (Table 11-4, p. 286).
Table 15-9. Key estimates of the effectiveness of airbags in
reducing fatality risk.
The triumph of ideological zeal
The 1977 NHTSA claim of a 40%
fatality reduction effectiveness for airbags, and the 12,100
lives per year it was stated would be saved by driver and
passenger airbags,20(Table II,p 34298) formed the basis for
the airbag mandate pursued with such tenacity by Claybrook.
As airbags deploy only in frontal crashes, which account for
about half of deaths, an overall effectiveness of 40% would
require about 80% effectiveness in frontal crashes. Such an
expectation is in stark violation of the knowledge the
science of biomechanics had established many decades
earlier. The 40% figure, plucked out of thin air, is not
just wrong; it is unrealistic, and arguably absurd. The 1973
GM study estimating 18% effectiveness was already available,
augmented by actual deployment experience from the GM fleet
of 10,000 airbag-equipped vehicles. The experience from this
fleet was inconsistent with effectiveness approaching the
NHTSA claims. NHTSA dismissed the GM findings, writing,
"The Department finds the methods used in the General
Motors study to be of doubtful value in arriving at an
objective assessment of the experience of the
air-bag-equipped vehicles. General Motors is a vastly
interested party in these proceedings, and the positions
that it adopts are necessarily those of an advocate for a
particular result."20(p 34292) The document continues
with a stream of baseless allegations and denies other
claims supported by technical information, claims that
subsequently turned out to be true. The case of an infant
killed by a deploying airbag in a modest-sized fleet of
10,000 airbag-equipped cars20(p 34294) is dismissed as
something anomalous that will never recur. The document
states, "Considering all the arguments on both sides of
the issues, the Department concludes that the observed
experience of the vehicles on the road equipped with airbags
does not cast doubt on the effectiveness estimates in the
December 1976 decision." 20(p 34292) The estimates
referred to are those in Fig. 15-5.
When the auto industry wanted to
delay or weaken the airbag mandate for reasons now
established beyond doubt to be valid, Nader claimed (based
on Claybrook's numbers) that each year of delay would mean
10,000 unnecessary deaths and 100,000 unnecessary disabling
injuries.18(p 113)
While Claybrook's NHTSA made unsupportable claims about the
benefits of airbags, the technical reports13,14 identifying
airbag threats to children were dismissed. A July 1980 NHTSA
report states, "air bags will provide substantial crash
protection to otherwise unrestrained small children in
crashes." (p 71) In the same document NHTSA cites, and
dismisses, statements by General Motors, based on their own
animal testing and other technical considerations, that a
"child might be injured by an inflating bag." 30(p
70)
Issues surrounding airbags and the mandate
A Claybrook aide is quoted as
saying, "Joan didn't do much on mandatory belt use
because her primary interests were in vehicle regulation.
She was fond of saying 'it is easier to get twenty auto
companies to do something than to get 200 million Americans
to do something.' "18(p 123) The something she wanted
the auto companies to do was to install airbags because they
were claimed to be passive devices, while safety belts were
active devices. Passive devices require no knowledge or
actions on the part of the users, while active devices
require users to do something, like fastening a belt.
A cornerstone of the support for
the airbag mandate was the belief that attempts to influence
the behavior of road users were futile. The nation's top
traffic safety official believed that Americans could never
be persuaded to wear belts. By contrast, the US surgeon
general (not a lawyer) believed that Americans could be
persuaded to stop smoking. He was right.
The support for airbags was based
on philosophical and ideological advocacy unrelated to
data-based performance measures. It was argued that it was
self-evident that passive solutions were superior. The
analogy that putting chlorine in the drinking water is a
more effective cholera countermeasure than a campaign to get
everyone to boil untreated water was considered persuasive.
The fact that no passive device that could protect occupants
in crashes existed, or was feasible, was denied. Affirming
as a tenet of belief that such devices existed prevented the
adoption of effective reality-based policies.
The airbag mandate prevented belt wearing laws
When other countries were following Australia's lead in
passing belt wearing laws, the number one priority of safety
leaders in the US was mandating airbags. Airbag-mandate
enthusiasts saw belt laws as a threat to their campaign. The
founder of an organization to advocate seat belt usage
states, "Nader's organization went after me, saying
that I was selling out the air-bag movement." (p 59)
Not only did Claybrook not support
mandatory wearing laws, she did not even accept that belts
were effective when used. In a November 1983 television
interview (transcribed below, and in Ref. ), Joan Claybrook
says of airbags:
"They're much better than seat belts, according to the
government's most
recent data,"
and continues to dismiss safety belts as
"the most rejected technology we have. So I believe
that airbags would add a great dimension to cars and car
safety, would protect all front seat occupants in those
types of crashes where 55% of the public is now
killed."
Claybrook continues,
"Airbags are really the best solution - they fit all
different sizes and types of people, from little children up
to 95th percentile males, very large males. … So they
really work beautifully and they work automatically and I
think that that gives you more freedom and liberty than
being either forced to wear a seat belt or having a car
that's not designed with the safety engineering we know
today."
Behavior CAN be changed - to save the airbag mandate
When it became clear in 1997 that deploying airbags were
killing occupants in otherwise harmless crashes, pressure
began to mount to rescind the airbag mandate. Airbag-caused
injuries are the only traffic injuries for which there is a
simple, feasible, enormously cost-effective countermeasure
that is:
100% effective.
100% passive.
Simply removing the device is a perfect solution. If it is
not installed in the first place, the safety benefits are
accompanied by reduced vehicle cost.
The former enthusiasts for passive
solutions vigorously rejected this simple, elegant, passive
solution. In a strange irony, the supporters of the airbag
mandate, who claimed that behavior could not be changed,
provided one of the clearest illustrations of how behavior
can be changed.
Those killed by airbags were mainly short female drivers,
and children and infants in front seats with passenger
airbags. A massive publicity campaign was mounted to
persuade short drivers to sit further from the steering
wheel, and to place children in rear seats. The success of
this persuasion is apparent in the sharp decline in airbag
inflation fatalities in Fig. 15-7.
The 90% decline in fatalities from
1997 to 2002 is mainly, but not exclusively, due to changes
in behavior. From model year 1998 onwards there was a
phase-in of second generation airbags that reduced the risk
of inflation-produced injuries. However, as it takes many
years for complete turnover of the fleet, much of the effect
is from changed behavior by owners of earlier airbags.
Figure 15-7 provides clear evidence
that road users were persuaded to change their behavior in
order to save the lives of themselves and their families. If
a similar effort had been applied to persuade people to
avoid the crashes that kill over 40,000 annually rather than
the airbags that were killing 50, dramatically more lives
could have been saved. Even if the persuasion was focused
only on occupant protection, persuading occupants to wear
belts while getting rid of airbags would have had an
enormously greater life-saving effect. More effort was
directed at saving the airbag mandate than on saving lives.
On-off switches. Even for vehicles, such as pickup
trucks, that do not have rear seats, the simple passive
solution of not installing airbags was still rejected.
Instead, off-on switches were installed which drivers were
instructed to place in the off position when transporting
children. As could have been predicted with certainty,
children were transported with the switch on (and adults
with it off).
Children in rear seats - a source of driver
distraction
One of the behavior changes
successfully promoted to save the airbag mandate was to
place children in rear seats to protect them from deploying
airbags. It is natural for children to demand, and receive,
parental attention. The study "The role of driver
distraction in traffic crashes" described in Chapter 8,
found that children were about four times, and infants
almost eight times, as likely as adult passengers to be a
source of driver distraction. The cover of that report is
reproduced in Fig. 15-8. The authors give more prominence to
the picture of the mother looking rearwards at her infant
than to the driver talking on a cell phone. In many
jurisdictions talking on a cell phone while driving, which
increases risk by more than a factor of four, is banned. Yet
placing children in rear seats is advocated as a safety
measure.
Summary of reasons for the airbag mandate
The mandate was enacted because advocates claimed that
airbags:
1. Are passive (require no user knowledge or action).
2. Replace belts (permit vehicles to not have belts).
3. Reduce driver fatality and injury risk by 40%.
4. Reduce risk regardless of gender, age, etc.
5. Hurt nobody.
All 5 claims are false!
Particularly false is the claim
that airbags are passive devices. Drivers, passengers, and
parents must know a list of rules on how to avoid death and
injury from deploying airbags. Arguably, airbags are the
least passive safety devices ever installed on vehicles.
Rather than being passive devices, they are belligerent
devices. The collapsible steering column is a truly passive
device - most of those benefiting from it do not know that
it is there. The manual belt
is a mixed passive/active device - the user has to know and
do little - just follow one simple rule, "buckle
up." The airbag is an active device which requires
major actions on the part of occupants, including insuring
that the distance
from their chest to the module is at least 10 inches, and
possibly adjusting the seat and fixing pedal extenders, and
placing children and infants in rear seats. And of course,
to avoid being killed by the airbag, the occupant must
fasten the safety belt.
Why did the auto industry go along?
Although the auto industry opposed
the airbag mandate prior to its enactment,18 it later began
to support and promote airbags. The auto industry had good
reasons to accept defeat graciously once the mandate was in
place, especially as continuing opposition would likely have
been futile. More importantly, NHTSA also administered fuel
economy standards which were more central to the industry's
business, so it made good business sense to avoid ongoing
friction on what became increasingly a settled historical
matter.
The well-publicized claims of unrealistically high airbag
benefits eventually generated consumer demand for airbags.
The auto industry, in common with other businesses, was
happy to sell in response to this demand, and also motivated
to increase the demand by its own advertising. The auto
industry installs, but does not generally manufacture,
airbags. As airbags represent about 2% of the cost of a
vehicle, the auto industry's earnings from them are a small
fraction of total earnings.
The airbag manufacturing industry
is totally committed to the mandate. What industry would not
want a law compelling people to buy its products even if
they did not want them? US consumers have paid over $60
billion for airbags. Most of this is in the pockets of
airbag manufacturers, who naturally use a portion of it to
lobby the political process to make sure that consumers
continue to be compelled to purchase their products.
Other items
US lacks academic safety institutions. Countries like
Sweden, Finland, the Netherlands, Australia, and New
Zealand, with populations and resources far less than many
US states, support important institutions devoted to
performing traffic safety research. There are university
departments, and scholars with titles like Professor of
Traffic Psychology. The researchers from these institutions
are invited to make technical inputs into policy-making. The
university research that is supported in the US is nearly
all in biomechanics and crashworthiness, reflecting the US
priority of attempting to squeeze small increments of
additional survivability in crashes rather than trying to
reduce crashes. Reviewing the world's safety literature
suggests that much of the best traffic safety research
performed in the US is by the auto and insurance industries.
The US would be well served if research addressing important
safety issues was conducted in university departments
receiving ongoing funding.
Blaming SUVs. The individuals who focused the
nation's safety efforts so narrowly on vehicle factors are
now blaming a vehicle, the SUV, for the nation's increasing
fatalities. The SUV's popularity is partially due to the
belief
that vehicle factors offering crash protection are the most
important safety factors. Another is due to the fuel economy
standards administered by NHTSA, which treat SUVs as light
trucks rather than cars (p. 88-91). While the shift to SUVs
influences fatalities, it could not be by more than a few
thousand per year up or down.
Regulating industry could save lives. If the lawyers
spearheading US safety policy wanted to wage war on industry
to improve safety, they would, if they had better understood
safety, have chosen different industries and issues. The
radar detector industry is not a major industry, but
restricting its products and marketing would benefit safety.
The industries that really impact safety are the alcoholic
beverage industry and the mass media. Effective regulation
of these would generate large safety benefits (Chapter 10).
If the advocates felt they had to fight with the auto
industry, there are two issues, which would really improve
safety, that the industry would likely have resisted. First,
regulating vehicle advertising to prohibit it from
glorifying irresponsible driving. Second, requiring an
inexpensive vehicle modification to prevent vehicles from
exceeding a set speed (police and emergency vehicles
exempted). Among the many lives that such a regulation would
save would be those lost in present high-speed police
chases, many involving stolen vehicles.
Where is US safety policy now?
The history of the airbag mandate
contains lessons that may eventually benefit US safety
policy. We must not forget George Santayana's celebrated
aphorism, Those who do not remember the past are condemned
to relive it.
However, it is not yet history. The most important elected
official with safety responsibilities, Senator John McCain,
has his door open to Claybrook, but closed to science, thus
keeping the same beliefs that led to the deaths of so many
still at the heart of the US approach to safety. Now that
NHTSA is acting more in the public interest, its
Administrator is subject to more severe political oversight
and criticism than occurred when it was making demonstrably
absurd claims.
The most extraordinary aftermath of the debacle of the
airbag mandate is that the architects of policies that led
to the deaths of 200,000 additional Americans are routinely
referred to in the mass media as safety advocates.
The importance of what the public believes
We have shown in earlier chapters
that driver behavior factors have by far the largest effects
on traffic safety. Driver behavior is largely determined by
what people believe, and what they believe is enormously
influenced by the mass media. The media do not merely report
on safety, I believe they largely determine it. Attitudes to
risk are based almost entirely on inputs from the media.
People have no direct experience of dangers from things like
cholesterol or radioactivity. Their concerns and protective
responses are almost 100% due to inputs from the media.
There are no data on how safety is treated by US media
compared to media in other countries today, or in the
mid-1960s when the US had the best safety. Nor are there
quantitative measures of safety attitudes in different
countries. However, having visited 51 countries and spoken
professionally about traffic safety in 25 of them, I have
come to some fairly confident conclusions based on observing
much media and interacting with large numbers of people in
many countries.
I perceive a clear difference in
attitudes between citizens of the US and citizens of
countries with superior safety performance. When I mention
traffic safety to an American, the response will likely
bring up vehicle safety, product liability trials, vehicle
defects, vehicle recalls, crash tests, specific vehicles
that have been in the news, airbags, etc. That is, a
collection of items focusing on the vehicle, all of which
are relatively unimportant to safety. A citizen of a country
with superior safety is far more likely to mention belt
wearing, drunk driving, speeding, and risky driving, items
that greatly influence safety. Of course the distributions
have much overlap, but there is an unmistakably clear
difference in the average answer of an American and a
non-American.
Safety and US mass media
I believe that the reason why
Americans think unimportant factors are important is due to
massive media coverage of the unimportant and meager
coverage of the important. Product liability trials seeking
massive awards are unique to the US, and receive major
coverage which does not include crucial information. A high
profile trial may perhaps involve a driver who was severely
injured (but not killed) after ejection in a rollover crash.
The public is, perhaps, informed that a tire manufacturer
was responsible, but not informed that the driver was
speeding and illegally not wearing the safety belt that
would have made ejection near impossible. In some states a
jury must be kept ignorant of the fact that an injured
plaintiff was not wearing a belt, even though such behavior
is illegal. Instead of providing evidence of consequences of
disobeying traffic law, US media coverage fosters the belief
that the problem is manufacturing and design decisions over
which drivers have no control.
The media conveys no sense that
during the period of a trial focusing on just one injury,
thousands of Americans were killed in crashes in which no
lawyer bonanza was identified. The US media is so supportive
of the process that they never ask the most obvious
questions. I have heard a television reporter ask a general
for details of his battle plan, but I have never heard a
reporter ask an attorney how much of the $5 million dollar
settlement went into his or
her pocket, how much went to the so called expert witnesses,
how much went for lavish travel and other expenses, and how
much (if any) went to the injured plaintiff.
In the course of a year, dozens of
US national television and radio news bulletins start by
reporting that a certain vehicle manufacturer has recalled
so many vehicles for a defect in, say, the ignition system,
and comment that there have been no injuries, or perhaps one
minor injury. Why should anyone who does not own one of the
vehicles be interested? The media claim that they are
responding to public interest is unconvincing. The public
would be far more interested in hearing the attorney explain
why his or her fees and the plaintiff's compensation should
be secret, especially if the explanations were followed by a
few sharp follow-up questions regarding what public or
safety interest is served by such secrecy. They would be
much more interested in having the attorney explain (or
refuse to explain) why the jury is prohibited from knowing
if a belt wearing law was violated.
The net effect is that Americans
are inundated with coverage of things that they are told are
related to safety, when in fact they have negligible
influence on safety. The view that safety is in the hands of
a few institutions over which they have no control, except
through litigation, is repeatedly reinforced. The reality
that the most important element in their own safety is their
own driver behavior is buried under a mountain of
misinformation.
US law at the heart of the problem
The unifying factor at the heart of
the failure of US safety policy is the uniquely powerful
role of litigation in every aspect of US society. No other
nation is burdened with anything resembling the US legal
system. In other democracies elected legislators with varied
backgrounds are influenced by inputs from diverse sources,
including the technical community. In the US, legislators,
who are overwhelmingly lawyers, get nearly all their inputs
from other lawyers.
While it might not be a conscious goal, it is not too
surprising that when lawyers are the main decision makers,
measures that open deep pockets for legal assault are more
appealing than measures that reduce harm. Since the period
when the US was the world's safety leader, litigation in the
US has exploded, and has been spectacularly successful in
directing focus away from countermeasures known to be
successful in favor of vehicle factors that are of minor
safety importance but are major sources of litigation
wealth. No impartial observer can imagine that any net good
emerges from the resulting system which lavishly supports a
pestilence of avaricious lawyers, "expert"
witnesses, consultants skilled at identifying jurors lowest
in knowledge and reasoning skills, and a vast court
superstructure. Even advocates of the US system rarely
conclude that US cars must be much safer than Swedish cars
because the US spends astronomically more per capita on
litigation than does Sweden.
It is unfortunately difficult for
anyone born in the US to be an impartial observer. Just as
certain propositions are off limits for discussion in
theocracies, in the US it is off limits to even discuss if
the legal system now exists mainly to benefit its members,
with everyone else compelled to pay an enormous law tax on
everything they do in order to insure that right is not
done. It is not uncommon for college educated Americans to
recite to me, like a catechism, the statement "The US
legal system is the best in the world". My response,
"Can you identify six ways the US legal system is
superior to that in Sweden?" generates a blank stare. I
keep going until "Can you identify one way in which the
US system is superior to that in any democracy?"
produces the same non-response. It seems being better than
the Soviet Union or the Third Reich is sufficient evidence
to self-award the best in the world title. Americans are
unlikely to demand changes to a system that is diminishing
their freedom, stealing their wealth, making the products
they purchase more expensive, less innovative, and less
safe, and killing them, if they really believe it is the
best in the world. It is difficult to be optimistic about
the future because the enormous wealth of the legal system
allows it to be the major financial contributor to the US
electoral process.
However, a cause for optimism is that once the US
does recognize it has a problem, it moves with a speed and
energy unequalled in other countries.
Specific differences
Ideally, one would like to account
for the 200,000 additional Americans killed between 1979 and
2002 in a list quantifying contributions from specific
factors. However, many of the likely contributions do not
readily admit to quantification. For example, it is
difficult to estimate the change in driver care caused by
repetitive messages implying that vehicle factors are
paramount.. There is, however, one factor for which a
quantitative estimate can be made.
Deaths caused by not having belt wearing laws
Canada's first belt wearing law was
in effect in January 1976 (in the Province of Ontario). The
first belt law in the US was in effect in December 1984 (in
New York State). It took additional years before all
Canadian provinces and nearly all US states had belt laws,
so that most Americans were covered by belt wearing laws
about a decade later than most Canadians. This delay had,
and continues to have, a large impact on US safety.
Figure 15-9 shows that once belt laws were in effect in the
US, belt wearing increased in a manner not dissimilar from
the Canadian experience (pre-law Canadian rates were around
25%). This is convincing evidence of the absurdity of the
claim by Claybrook's NHTSA that Americans would not wear
belts. The evidence shows that drivers in the US were not
all that different from those in Canada. The longer laws are
in effect, the easier it is to strengthen them by, for
example, moving from secondary to primary enforcement. Thus
rates increase, but over long periods of time. The lower
present rate in the US is due primarily to the US starting a
decade later than Canada.
Figure 15-9. Increases in belt wearing rates in Canada (first belt law January 1976) and in the United States (first belt law December 1984).
The consequences of this late
start, computed in Table 15-10, show that the late passage
of mandatory belt wearing laws was responsible for an
additional 96,000 American deaths from 1979 to 2002. The
parallel comparison with Britain gives a larger difference,
and with Australia, a much larger difference.
It could be argued that the 96,000 extra US deaths should be
reduced by deaths prevented by mandated airbags.
Extrapolating even the highest estimates to the 1979-2002
period produces a total that falls well short of 10,000,28
leaving a net increase due to not having mandatory wearing
laws in excess of 86,000. Studies from Transport Canada ,
estimate that, during the eleven-year period 1990-2000,
belts prevented 11,690 Canadian deaths, and airbags 313.
The one specific policy of pursuing the airbag mandate and
not working for mandatory belt laws accounts for about half
of the additional 200,000 US fatalities.
Table 15-10. Reductions in US fatalities if belt use
rates in the US had matched those in Canada.
belt wearing rates (%) observed US fatalities* F** US
fatality reduction with Canadian belt use
Other specific differences
While other countries developed
policies aimed at driver behavior, the US paid less
attention to drivers, instead concentrating most effort on
vehicle factors.
Drunk driving. The per se limit in the US during
1979-2002 was substantially higher than in any comparison
country. For most states it was BAC > 0.1%. It was not
until 2000 that the US Congress passed legislation providing
financial incentives for states to have BAC > 0.08% laws
in effect by 2004. During the time when the airbag mandate
was being debated some even argued that the most effective
approach to drunk driving was to have airbags in all
vehicles. After all, this would reduce deaths to drunk
drivers and most of their other victims by 40%, while
policies aimed at changing such behaviors as drunk driving
were doomed to failure. In Chapter 10 a number of measures
that could substantially reduce annual deaths from drunk
driving are described. The largest progress in reducing harm
from drunk driving resulted not from government leadership,
but from the creation in 1980 of Mothers Against Drunk
Driving (MADD). As MADD helped change laws, government had a
law-enforcement role in these harm reductions. Without MADD,
US fatalities would exceed those in the comparison countries
by even larger amounts.
Speed. Even though one of the largest reductions in
US casualties was associated with reductions in the speed
limit in response to the 1973 oil embargo, speed limits were
later increased. How increasing speed affected safety was
addressed in the normal US advocacy manner. Those who liked
higher speed limits argued they would not affect safety,
while their opponents argued that they would. There was
little sense that this was a technical question that had a
technical answer. This is where the US pays a safety price
for not having research institutions that can provide
technical results that the public finds credible. Even those
who enjoy ice cream tend to accept that it is not a health
food because they respect the qualifications and motivations
of the experts providing them medical information.
Radar speed detectors. Devices to detect police radar
are vigorously marketed in the US. These have only one
purpose - to assist in violating traffic law. This is why
they are prohibited in Canada. I believe the difference is
another reflection of the US regarding safety more in terms
of making vehicles safe to crash rather than in preventing
crashes. It is not related to respect for personal liberty.
The liberty of a short lady to purchase an airbag-free
vehicle is denied by the US government. The US is far more
ready than other countries to put people in prison for
consuming specified drugs in the privacy of their homes.
While consuming harmful drugs may be deplorable, it does not
directly and immediately threaten other people's lives as
does speeding. Not all of the countries with better
performing safety records prohibit radar detectors. All
countries have major inadequacies in their safety policy.
Epilogue
The anti-technical lawyer zealots who
defined and led US policy precipitated a massive safety
disaster that continues. If a fraction of the energy and
tenacity devoted to counterproductive policies had been
applied to promote effective policies, the US could have
remained the world's traffic safety leader. Goethe
(1749-1832) perhaps best summarizes what in fact happened:
There is nothing more fearful than ignorance in action.
Summary and conclusions (see printed text)
References for Chapter 15 - Numbers in [ ] refer to superscript references in book that do not correctly show in this html version. To see how they appear in book see the pdf version of Chapter 1.
[1] Motor Vehicle Manufacturers
Association of the United States. MVMA Facts and Figures
1981. Detroit, MI; 1981.
[2] International Road Traffic and
Accident Database (OECD) (2002). March 2004.
http://www.bast.de/htdocs/fachthemen/irtad/english/englisch.html
[3] Department for Transport. Transport statistics, Table 9.10. Road accidents and casualties: 1950‑2002. http://www.dft.gov.uk/stellent/groups/dft_transstats/documents/page/dft_transstats_506740.xls
[4] Transport Canada. Canadian motor
vehicle traffic collision statistics: 2002.
http://www.tc.gc.ca/roadsafety/tp/tp3322/2002/menu.htm
[5] Australian Transport Safety
Bureau. http://www.atsb.gov.au/road/stats/current.cfm
[6] Evans L. Transportation Safety.
In: Hall RW, editor. Handbook of Transportation Science,
Second Edition. Norwell, MA: Kluwer Academic Publishers;
2002, p. 67-112.
[7] Evans L. Traffic crashes. Am
Scientist. 2002; 90: 244-253.
[8] Paulikas GA. Measuring risks (Letter to the editor responding to previous reference). Am Scientist. 2002; 90: 300. (Followed by Evans L. Dr. Evans replies – on same page).
[9] Complete details of this and
other calculations are available at
http://www.ScienceServingSociety.com/data.htm
[10] Evans L. A new traffic safety
vision for the United States. Am J Public Health. 2003; 93:
1384-1386.
[11] Vernick JS, Teret SP. Making
vehicles safer. Am J Public Health. 2004; 94: 170.
[12] Evans L. Evans responds (to
previous reference). Am J Public Health. 2004; 94: 171-172.
[13] Patrick LM, Nyquist GW. Airbag
effects on the out-of-position child. SAE paper 720442.
Warrendale, PA: Society of Automotive Engineers; 1972.
[14] Aldman B, Anderson A, Saxmark O.
Possible effects of air bag inflation on a standing child.
Proceedings of the 18th Annual Conference of the American
Association for Automotive Medicine, Toronto, Canada, 12-14
September, 1974.
[15] Aldman B, Anderson A, Saxmark O.
Possible effects of air bag inflation on a standing child.
Proceedings of the International Research Council on the
Biomechanics of Impact, Meeting on Biomechanics of Trauma in
Children, Lyon, France; September 1974.
[16] Glass RJ, Segui-Gomez M, Graham
JD. Child passenger safety: Decisions about seating
location, airbag exposure, and restraint use. Risk Analysis,
2000; 20: 521-527.
[17] Counts for air bag related
fatalities and seriously injured persons.
http://www-nrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/SCI/2Q_2003/HTML/QtrRpt/ABFSISR.htm
[18] Graham JD. Auto Safety: Assessing America’s Performance. Dover, MA: Auburn House Publishing Company; 1989.
[19] Wilson RA, Savage CM. Restraint system effectiveness – a study of fatal accidents. Proceedings of Automotive Safety Engineering Seminar, sponsored by Automotive Safety Engineering, Environmental Activities Staff, General Motors Corporation; 20-21 June 1973, p. 27-38.
[20] Federal Register, Vol. 42, No 128, Part 571 – Federal Motor Vehicle Standards: Occupant protection systems, Docket No. 75-14, Notice 10, pages 34289-34305; 5 July 1977.
[21] Kent R, Viano D, Crandall J. The field performance of frontal air bags. In: Kent RW, editor. Air Bag Development and Performance – New Perspectives from Industry, Government, and Academia. SAE Special Publication PT-88. Table 14, Chapter 5. Warrendale, PA: Society of Automotive Engineers; March 2003
[22] Pursel HD, Bryant RW, Scheel JW,
Yanik AJ. Matched case methodology for measuring restraint
effectiveness. SAE paper 780415. Warrendale, PA: Society of
Automotive Engineers; 1978.
[23] Segui-Gomez M. Driver air bag effectiveness by severity of the crash. Am J Pub Health. 2000; 90: 1575–1581.
[24] McGwin G Jr, Metzger J, Jorge E, Alonso JE, Rue LW III. The association between occupant restraint systems and risk of injury in frontal motor vehicle collisions. J Trauma. 2003; 54: 1182–1187.
[25] McGwin G Jr. Airbags and the
risk of injury in frontal motor vehicle crashes. 2003.
Submitted for publication.
[26] National Highway Traffic Safety
Administration. Final regulatory impact analysis, Amendment
of FMVSS 208, passenger car front seat occupant protection.
Washington, DC; 11 July 1984.
[27] Kahane CJ. Fatality reduction by
air bags: Analysis of accident data through early 1996.
Report DOT HS 808 470. Washington, DC: National Highway
Traffic Safety Administration; 1996.
[28] National Highway Traffic Safety
Administration. Fifth/Sixth Report to Congress:
Effectiveness of occupant protection systems and their use.
Report DOT HS 809 442. Washington, DC: US Department of
Transportation; November 2001.
[29] Cummings P, McKnight B, Rivara FP, Grossman DC. Association of driver air bags with driver fatality: A matched cohort study. Brit Med J. 2002; 324: 1119–1122.
[30] National Highway Traffic Safety
Administration. Automobile occupant crash protection,
progress report no. 3. Report DOT HS 805 474. Washington,
DC: US Department of Transportation; July 1980.
[31] Gladwell M. Wrong turn: How the fight to make America’s highways safer went off course. New Yorker. 11 June 2001, p. 50-64. http://www.gladwell.com/2001/2001_06_11_a_crash.htm
[32] Hearing before the Subcommittee
on Telecommunications, Trade and Consumer Protection of the
Committee on Commerce, House of Representatives.
Reauthorization of the National Highway Traffic Safety
Administration. Serial No. 105-30, Attachment D. Washington,
DC: US Government Printing Office; 22 May 1997.
[33] Morgan C. Results of the survey
of the use of passenger air bag on-off switches. Report DOT
HS 809 689. Washington, DC: US Department of Transportation,
National Highway Traffic Safety Administration; November
2003.
[34] Stutts J, Feaganes J, Rogman E,
Hamlett C, Meadows T, Reinfurt D, Gish K, Mercadante M,
Staplin L. The role of driver distraction in traffic
crashes: Distractions in everyday driving. Washington, DC:
AAA Foundation for Traffic Safety; July 2003.
http://www.aaafoundation.org/pdf/DistractionsInEverydayDriving.pdf
[35] Redelmeier DA, Tibshirani RJ.
Association between cellular-telephone calls and motor
vehicle collisions. New Eng J. Med. 1997; 336: 453-458.
[36] O’Donnell J. Republican senator, auto-safety advocate form unlikely alliance. USA Today. 28 July 2003. http://www.usatoday.com/money/autos/2003-07-28-cover_x.htm
[37] Blair D. Seat belt defense
deserves a fair hearing in Texas (editorial). Houston
Chronicle. 17 February 2003.
[38] Huber PW. Liability: The Legal
Revolution and its Consequences. New York, NY: Basic Books;
1988.
[39] National Academy of Engineering.
Product Liability and Innovation. Washington, DC: National
Academy Press; 1994.
[40] Safety belt use laws. Insurance
Institute for Highway Safety, Safety Facts.
http://www.highwaysafety.org/safety_facts/state_laws/restrain3.htm
[41] Chaudhary NK, Preusser DF. Lives lost by states’ failure to implement primary safety belt laws. Report prepared for the National Safety Council’s Air Bag & Seat Belt Safety Campaign. November 2003. http://www.nsc.org/public/Preusser_Study.pdf
[42] Transport Canada. Estimates and
lives saved among front seat occupants of light-duty
vehicles involved in collisions attributable to the use of
seat belts and air bags in Canada. Road Safety and Motor
Vehicle Regulation, Fact Sheet RS 2001-03 E TP13187E;
October 2001.
http://www.tc.gc.ca/roadsafety/tp2436/rs200103/en/menu.htm
[43] Stewart DE, Arora HR, Dalmotas D. An evaluation of the effectiveness of supplementary restraint systems (“air bags”) and conventional seat belts: Estimates of the numbers of lives saved among front seat outboard occupants of light-duty vehicles involved in collisions attributable to the use of seat belts and the fitment of supplementary restraint systems (“air bags”) in Canada, 1990-1997. Publication Number TP13187 E. Ottawa, Ontario: Transport Canada; 1998.