Lesson from the continuing 21st century motor vehicle success

The 20th century motor vehicle success story

Every professional in the injury field knows the story. It is the one we tell our graduate students over the campfire so it can be passed down from generation to generation. The true story is more nuanced, but the broad outlines of this mortality tale are correct.

From the dawn of the automobile age until the 1950s, the focus of traffic safety efforts was on the driver. After all, if drivers never made mistakes, there would be hardly any motor vehicle (MV) crashes, and if drivers never deliberately disobeyed the law (eg, speeding, drunk driving) most MV deaths would be eliminated. From these observations came the policy mantra of education and enforcement (train drivers and punish offending ones).

After World War II, public health physicians began asking a different question—not who caused the crash, but what caused the injury? Drivers were being killed in head-on collisions when their chest hit an unyielding steering column, and their faces were being lacerated when they hit windshields made of regular non-tempered glass. Occupants were thrown from the car and their heads would hit the car hood or the pavement causing fatal brain injury. When cars veered off the road they often crashed into lampposts and trees which had been deliberately placed along the sides of highways, causing blunt force to the body resulting in injuries to the brain and internal organs .

The public health physicians asked, why can’t cars be made safer, with collapsible steering columns, windshields made of safety glass, seatbelts, airbags, and crash-worthy interiors? Why can’t the roads be made safer? After all, no one was installing lampposts alongside airport runways.

Bill Haddon, MD, MPH, was one of those public health physicians. Borrowing from epidemiology, he created what is now known as ‘the Haddon matrix’—a simple tool that is taught in all injury prevention classes. The matrix highlights the idea that many different policies can reduce injury—including changing the agent of injury (eg, the car) and the environment (eg, the road).

In 1966, Haddon became the first administrator of what became the National Highway Traffic Safety Administration (NHTSA). During his brief tenure, the agency issued the first safety requirements for new vehicles, including for shoulder belts, laminated windshields, energy-absorbing steering columns and side door beams. On leaving NHTSA, Haddon became president of the Insurance Institute for Highway Safety (IIHS), a non-profit organisation supported entirely by automobile insurance companies. The mission of the IIHS is to reduce deaths, injuries and property damage from MV.

By the turn of the century, although drivers overall did not appear to be much better than they were in 1966, (drivers were better about alcohol, worse about distracted driving), between 1966 and 2000, the rate of fatalities per vehicle mile driven had fallen over 70%. The societal effort to reduce traffic injuries was so successful that, in 1999, the Centers for Disease Control and Prevention (CDC) proclaimed the reduction in MV fatalities as ‘one of the great public health achievements of the 20th Century.’1

The 20th century MV success story has had an enormous intellectual impact on the injury prevention field, providing many guiding lessons. Here are four:

You don’t need to change the behaviour of the user—the individual with the last clear chance to prevent injury—to dramatically reduce injuries. Most of the credit for the MV success story was due to changes in MV, roads and the emergency medical system, not due to better driving.

Policies can reduce the number of injured motorists without affecting the number or types of crashes. Many safety improvements, such as seat belts, airbags, collapsible steering columns and child car safety seats, do not reduce the likelihood of collision—instead they reduce the likelihood of serious injury once a crash occurs.

A harm reduction approach can be effective. Virtually everyone can still own and drive cars, but now they can do so with lower risk of serious injury. NHTSA did not ban any cars, except for new cars without collapsible steering columns, shoulder belts, etc.

You don’t need to find a single ‘silver bullet’ solution. The MV success was due not to a few major changes, but to scores of improvements—using a multipronged approach—in cars, roads, medical care and drivers.

New lesson from the 21st century MV success

The reduction in the MV death rate was a 20th century injury prevention success story. Are there any lessons the injury field can learn from what has happened to MV safety in the first two decades of the 21st century? We believe there are many potential lessons, but we want to highlight one: The great injury public health achievement of reducing the MV death rate did not stop in 2000—it continued.

For at least 60 years, injuries caused more deaths to children and youth 1–24 years old than were caused by all diseases combined and the leading cause of injury death was always MV deaths. In the final two decades of the 20th century, the MV death rate per population for 1–24 years old fell by more than 40%. What happened in the first two decades of the 21st century (2000–2020)? The MV death rate for this age group fell 39%!2 By 2017, for this age group, MVs were no longer the leading cause of injury death.3

According to the CDC, the public health approach to injury prevention is a four-step process: define the problem, identify risk and protective factors, develop and test prevention strategies, and assure widespread adoption. The 20th century MV success story suggested a slightly difference approach: create a system where it is difficult to make mistakes and difficult to behave inappropriately, and then if some people still do, make it unlikely that anyone will get hurt. These are both reasonable synopses of the injury prevention approach—but neither acknowledges the importance of creating conditions for continuous improvements over time.

The goal of continuous quality improvement has become a staple in medicine. By contrast, even the idea of creating the conditions for continuous reductions in serious injury and fatalities has not been emphasised in the injury prevention field. We are not arguing that we should use the same methods as medicine, but simply that we should begin to focus on the strategic notion of creating the right environment, and the right incentive structures, to help ensure that progress will be continuing. Our field does not differentiate one-off polices that lead to a once-and-for-all injury reduction vs those that provide the conditions for ongoing improvements over time. Thus, we do not do nearly enough to promote policies leading to continuous advances compared with policies that will yield beneficial, but one-time change.

For illustrative purposes, we will compare some potential ingredients for continuous reductions in injuries from MVs verses from firearms. There has certainly been very different 21st century trends in these two types of injury. For the 1–24 years old group, while MV death rates have fallen rapidly over the past two decades, firearm death rates have not fallen at all. In 2000, for this age group, MV death rates were 87% higher than firearm deaths. By 2020, firearm deaths were 24% higher than MV deaths. Firearms are now the leading cause of injury death for American youth.3

What caused this reversal? We don’t have the full answer. However, it seems likely it was due, at least in part, to the fact that a system for continuous improvement appears to have existed for MVs but did not exist for firearms. (1) We had a federal agency—the NHTSA—whose sole mission is to save lives and prevent injuries due to road traffic crashes. By contrast, firearms remain one of the very few products with no federal agency overseeing its safety. (2) The automobile industry has been subjected to many product liability suits. By contrast, firearm manufacturers and sellers are provided special protections against certain important types of tort claims. As a result, they bear little accountability for the damage done by firearms and little financial incentive to reduce the harm. (3) Insurance liability has not only provided some safety incentives to car manufacturers and motorists, but the insurance industry financially supported the non-profit IIHS. IIHS crash-tests cars, rates vehicles and safety devices such as child booster seats, conducts research and promotes public policies for reducing traffic injuries. By contrast, insurers play little role in promoting firearm safety; (4) The federal government (in large part through NHTSA) has had excellent, long-established data systems, for all MV-related deaths on public roads and a large nationally representative sample of police reported crashes. By contrast, it took the first two decades of the 21st century to finally complete the national database that includes the circumstances of all firearm deaths (the National Violent Death Reporting System) and we still lack a reliable database for non-fatal firearm injuries; (5) While there has been and continues to be substantial federal research funding for MV injury prevention, there was an effective effort to prevent federal funding for firearm research—it is only since 2019 that there has finally been a substantial increase in funding for firearm research (though at levels still not nearly commensurate with the size of the problem). Not surprisingly, much more is known about the circumstances of MV deaths and effective prevention interventions than is known for firearms; (6) At the state level, licensing of motorists and registration of MVs not only directly helps reduce injuries but allows for many effective safety regulations. For example, between 1997 and 2006, all states enacted graduated licensing programmes for new drivers (reducing their fatalities by 30%).4 By contrast, few states have either licensing of gun owners or registration of guns.

It appears that our traffic safety infrastructure has helped create a conducive environment for continuous safety improvements. The government and the insurance industry objectively measure the safety of MVs (eg, crash testing) and help to effectively disseminate that information. Consumers have the information to reward the manufacturers of safe vehicles. Not surprisingly, automobile makers, who had historically resisted competing on safety, reversed course and now commonly promote their safety improvements. New cars today are much safer than they were at the beginning of this century. For example, automatic emergency braking, electronic stability controls, lane departure warnings, blind spot detection, side airbags and rear-facing cameras are commonly available. Much of the 21st century reduction in MV deaths to 1–24 years old has been due to the reduction in the rate of death to MV occupants—which fell 67% in the past two decades.2

By contrast, it has been difficult to find any conditions involving firearms that might have been expected to lead to continuous reductions in firearm injury. Indeed, in the past two decades, firearms for sale became more lethal rather than safer, as manufacturers increasingly sold weapons designed for military use. There has been near universal opposition by gun manufacturers to many changes in firearms which might reduce firearm deaths. In 2000, for example, the CEO of gunmaker Smith and Wesson agreed with the Clinton administration to put trigger locks on all its guns, develop guns that only authorised users could fire (personalised ‘smart’ guns) and take steps to prevent the company’s dealers from selling guns illegally. The agreement to these safety measures enraged the gun lobby. The industry boycotted Smith and Wesson, telling their dealers to stop selling Smith and Wesson guns. The company’s sales plummeted, and the Smith and Wesson CEO was replaced.5 In the 20 years from 2000 to 2020, the rate of firearm deaths to 1–24 years old increased 41%. This hardly seems like a coincidence given the increasing number and lethality of firearms owned by Americans.

In this essay, we are not trying to provide the best blueprint for reducing firearm injuries. Nor will we present a set of principles or tactics that could be used to effectively reduce firearm injuries (eg, understand and respect the culture, forge coalitions). Our discussion of firearms is simply to illustrate a system that, in contrast to MVs, does not currently appear to have the ingredients that promote continuous reductions in injury. We believe the big lesson from the 21st century traffic safety story is that it does seem to be possible to create the conditions which will help lead to continuous reductions in serious injuries and deaths over time. The injury prevention field needs to devote more energy to determining what policies best promote continuous safety improvements and then to promote those policies. In addition to determining the one-off policies which are effective in decreasing injury, we should also figure out how best to measure, encourage, and institutionalise continuous safety improvement.

Researchers (like ourselves) need to do more to understand what are the key ingredients for continuous injury reductions over time. A first step would be to learn the reasons for long-term trends in different types of injury. For example, longitudinal studies might help us understand why, in the first two decades of the 21st century (baseline 2000 through 2020), for ages 1–24, per capita, residential fire rates deaths fell by 64%, drowning deaths fell 23%, while the motorcycle death rate rose by 20%.2

There may be an even greater need for more cross-national longitudinal injury prevention studies. For example, while we continue to congratulate ourselves about our success in reducing MV fatalities, it should be recognised that most other high-income countries have improved much faster than we have in the past 40 years, and we don’t seem to really understand why. Reports sometimes point out differences in MV death trends across nations, but they largely rely on expert opinion to try to explain the differences, not in the trends but in the current rates. It is important not only to explain why other countries are doing so much better than we are today, but why they improved so much faster than we did over the past 40 years. As Bill Haddon was fond of asking, where are the (scientific) studies?

In summary, we believe it is useful to distinguish between policies and programmes that (primarily) create and maintain the conditions for continuous reductions in injury over time, and those that (primarily) are one-off policies that reduce injury but do not produce conditions for further reductions. We believe that distinction has not been sufficiently made in the literature, and, indeed that the injury field has not even begun to determine what conditions are most essential for continuous reductions in injuries. Certainly, virtually all of the injury evaluation literature focuses on the effects on injury outcomes of what might be considered one-off policies.

We highlight some aspects of the MV system that appear to us to be useful ingredients for continuous improvement (eg, data systems, research funding, NHTSA). However, we are not presenting them as the best or only ingredients. We are saying that we believe the injury field should conduct studies to determine which conditions best promote the goal of continuous injury reductions and then we should try to create and protect those conditions.

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