Photo by Jan Vašek, 2017

umans are not indestructible like cartoon characters or gods. Yet throughout history, we have sought to move across the ground, water, and more recently through the sky, at ever increasing speeds — the very conditions most likely to cause irreparable harm should something go awry. Why do we do it?

Even a cursory look at the history of transportation shows an obvious trend towards moving faster. The mysterious part is that there is so little discussion regarding why we want to go faster. The attraction to speed was more understandable back when life was more dangerous and people had a stronger sense of fate. However, in our modern age of scientific introspection, average life expectancy has steadily risen and society is now more risk-averse and safety-focused than ever before. Nothing is outside the bounds of our potential control and no risk is too obscure to fret over. Our medicine bottles have child-proof caps, our power tools have safety guards, and our outlets have shock protection. We ban chemicals that we find to be dangerous and recall toys that cause too many injuries. We avoid trans-fats and smoking. And yet, when we strap ourselves into a vehicle stuffed full of mandated safety features, we often needlessly increase the primary reason the vehicle is dangerous in the first place — speed.

Sure, we have speed limits, but they don’t prevent all injuries (even when they are followed). So what are they based on? We will come back to the speed limit question later, but for now let us suffice with the simple answer that a speed limit is a trade-off between safety and speed. We generally don’t question the basic desirability of safety. As psychologist Abraham Maslow proposed, in the hierarchy of human needs, safety is a psychological requirement second only to our basic physiological needs (air, water, food, sleep, etc.). Yet, despite the obvious importance of self-preservation, we are willing to risk it all in order to travel quickly. This willingness to trade safety for speed requires further inspection. Why do we like speed so much? There appear to be three complementary explanations for why we are obsessed with speed, as well as a practical solution for controlling this questionable urge.

Union Pacific train “Pony Express” in 1949, Rocky Mountain Railroad Club

Speed, the Giver of Time

The first reason we like speed is pragmatic. Moving faster allows us to get to a destination in a shorter amount of time. Presumably, this saved time can then be used to do something else. In economic terms, this is the opportunity cost of traveling. Time spent in transit could be spent more productively on some other activity. The idea is popularized by Benjamin Franklin’s admonition, “Remember that time is money.” However, the idea dates back at least to ancient Greece when Antiphon of Rhamnus said, “The most costly outlay is time.” This notion of time-as-money makes high-speed travel seem prudent (well, at least financially prudent). Life is finite and moving faster allows one, in theory, to accomplish more. In the 2004 book, In Praise of Slowness, Carl Honoré offers a rare in-depth exploration of how this assumed value of speed has permeated almost every facet of modern society.

While time is indeed the most finite and precious of commodities, it’s less obvious that travel time is “wasted” time. If you are taking mass transit, it is perfectly feasible to work while traveling. But even less conducive forms of transportation are not black holes of unproductivity. I briefly endured a 3-hour daily work commute via automobile many years ago. While I did not enjoy the experience, I did manage to listen to many audiobooks while driving. The commute may have been environmentally wasteful, but it wasn’t unproductive. Counterintuitively, very slow travel can even be a producer of time. Traveling by foot or bicycle is excellent exercise that may actually add years of time to the traveler’s life.

The problem with equating speed with money is that it only directly applies to professional truck drivers who are paid by the mile. Even taxi drivers get paid by time, not just distance. While the idea that “time is money” may be popular, it’s not clear that it actually describes our behavior. The experience of urban planners in the last century has shown that if you give people bigger highways and faster cars to reduce their commute times, they don’t necessarily use the extra time to be more “productive.” Rather, they often increase their commuting distance to obtain housing they find more desirable. Sometimes this saves them money, but sometimes it’s a lifestyle choice that costs even more. Long commuters are trading time for something else they desire and speed just gives them more options.

So the value of time and how it relates to speed is complicated. There are certainly situations where speed does equal time saved. If one is trying to get to a far-away holiday destination and only has a few days of vacation, getting there as quickly as possible is the priority. Yet, there are also others who see the travel itself as the vacation and would prefer to spend all their free time touring cross-country. Intent is important. The relative utility of speed for a business trip is different than for a pilgrimage.

The inadequacy of the utility-of-speed explanation may best be shown by the following common example. Let’s say that a navigation system presents two time-equivalent routes to get to a destination. Do you take the shorter route that has more traffic or do you take the longer route with less traffic? If both routes take the same time, the theory of speed-as-a-time-management-tool suggests that we will randomly pick one, yet most people will consistently choose to avoid traffic. There is something particularly frustrating about sitting in traffic and something pleasurable about moving freely. A 2017 survey of 850 New Zealand drivers found that only one-third agreed that time savings was the reason they exceeded the speed limit (they were also bad at estimating how much time speeding actually saved). This suggests that we need another explanation for why people desire to move fast.

Photo by Hans Peters, 1971

Love of Speed

This leads to the second explanation for our compulsion for speed. One simple observation is that humans love the feeling of moving fast — even when it accomplishes nothing at all. Without the need to catch something, nor the fear of being chased, we sometimes run just for the fun of it. It’s a nearly universal human characteristic to enjoy sensations of speed and acceleration. It’s the basis for almost every amusement park ride ever invented. Perhaps what is even more interesting than our love of speed is our unwillingness to name it. The term “tachophobia” is an accepted word in the English language for the fear of speed. Yet, an opposite term, such as “tachomania” or “tachophilia,” is never used. The closest terms are the slang “speed demon” or “adrenaline junkie” which connote more than just the love of moving fast. I’ll leave it to someone else to unpack that mystery.

Suffice it to say, most of us enjoy moving fast. It’s part of our culture. Fast moving vehicles and chase scenes have been popular in movies since the dawn of film. We also enjoy vicarious displays of speed through sports. Of the most recent Olympic Games, almost half of the more than 400 combined summer and winter individual events are centered on speed. That is, the activity — be it rowing, running, cycling, swimming, skating, or skiing — are won based on who is the fastest. To do something well is admirable, but to do it faster than anyone else is worthy of accolades.

Tracing the lineage of racing for entertainment could fill volumes itself, but it also shows two trends. First, sport racing is universal. If a mode of transportation could be used for fun, someone tried it almost immediately. We can only assume that they will eventually be racing rocket ships (Whoever gets to Mars first, wins!). The second observation is that each new mode of transportation (foot, horse, automobile, airplane, etc.) tends to be faster than what came before it. Thus, the excitement and danger increases. Yet, rather than inducing caution, increasing speed may have the opposite effect. The ability to regularly travel at high speeds inures people to its natural thrill. Having become accustomed to moderate speeds, faster speeds are required to stay on the hedonic treadmill. Each new form of transportation must be quicker than the one that came before it if it is to catch the public eye. The potentially deadly becomes prosaic as long as actual catastrophe remains relatively rare.

Anyone who has driven a long distance has likely experienced a version of this habituation to speed. At the beginning of a trip, the traffic seems to be moving briskly and many vehicles are passing you. As the trip continues, you notice that your speed is creeping up to keep up with the flow of traffic and it no longer seems to be moving so fast. By the end of the trip, you are driving noticeably faster than when you started and it feels comfortable. The longer the trip, the stronger the effect.

Yet something prevents us from driving faster without limit. John Tomlinson’s 2007 book, The Culture of Speed, provides an academic sociological analysis that separates the cultural conception of mechanical speed into two competing drives: a utilitarian capitalistic ”rational-progressive speed” that emphasizes the efficiency of speed versus a hedonistic “unruly speed” that enjoys the excitement and potential violence of speed. In this later categorization, the inherent danger of speed becomes a feature, not an unfortunate side-effect. While “unruly speed” certainly appeals to a certain segment of society, such as participants in extreme sports, its influence on the general public is broad, but shallow. There are limits to our enjoyment of speed — not everyone wants a sports cars. The popularity of amusement parks is grounded on their underlying reputation for safety. If an amusement park ride results in actual injury, people are horrified and the ride is immediately shut down. It is merely the appearance of danger accompanying the speed that is enticing. We like our thrills constrained.

Photo by formulanone, 2014

How bad could it be?

This leads us to our third and last explanation which finds the widespread desirability of speed to be a risk perception problem. That is, we live in the present moment enjoying our time savings and thrills while underestimating the personal risks of speed.

Perhaps the simplest comparison of speed to safety can be made with trains. According to the U.S. Department of Transportation, traveling by rail is the safest common mode of transportation — about 1 person dies per 100 million miles of train travel — yet high-speed train travel is inherently more dangerous than low-speed travel. Let us compare three train accidents that occurred within months of each other in 2013. The first accident occurred when two NYC Metro North commuter trains collided and derailed as they passed each other in Bridgeport, CT. Of the over 500 combined passengers, there were no deaths. In the second accident, a train traveling out of Paris derailed killing 7 of the 385 passengers. In the third, a train traveling from Madrid to Ferrol, Spain derailed resulting in 79 deaths out of 218 passengers. Why the difference in fatality rates among the accidents? In this case, the American train had slowed to 23 mph before collision, the French train was traveling at about 85 mph, and the Spanish train was traveling almost 120 mph. When accidents occur, high-speed accidents are always more serious.

So, why don’t people just travel slower? Unfortunately, it’s not as simple as educating everyone to the true objective risks of speed. Risk management is not just calculating probabilities and consequences. It’s also about personal risk tolerance, cultural practices, and moral obligations. In other words, it’s unavoidably subjective. Like many seemingly intractable public problems, speed-seeking is a behavior implicitly condoned by society because it is widely practiced and rarely shunned. It also provides immediate gratification along with remote risks of immediate harm — all the qualities that discourage humans from behaving prudently.

In the field of risk analysis, it’s well-known that people do not treat all types of risks the same. For example, people tend to fear rare risks more than commonplace ones, uncontrollable risks more than controllable ones, and imposed risks more than voluntary ones. This explains why we generally fear terrorism (an uncommon, uncontrollable, imposed risk) more than driving (a common, self-controlled, voluntary risk) even though motor vehicles kill far more Americans than terrorism. This is reflected in our federal budgets where spending for traffic safety is a fraction of that spent on various counter-terrorism programs.

The problem is that we tend to underestimate the risks we are most “comfortable” with and speed is a perfect example. Driving is one of the most dangerous activities we perform on a regular basis. About 100 Americans die every day due to automobile accidents putting it in the top 15 leading causes of death and the leading cause of death for adolescents. But, since cars are ubiquitous, it’s easy to become complacent about their danger. Our misplaced fears have led us astray.

Of course, most of us can’t stop driving tomorrow, but do we need to do it quite so fast? But how fast is too fast? To answer that question, we return to how speed limits are set. While speed limits are officially set by politicians or technocrats operating on their behalf, the basis for a speed limit typically originates from one of several methods: an engineering study that considers the use and design of a road, expert judgment, transportation cost optimization, or injury minimization (which tends to result in the lowest speed limit). The details of the overall process are elaborate — the Federal Highway Administration’s guidelines for setting speed limits is over 100 pages long.

However, the various technical methods still don’t get to the heart of what constitutes acceptable risk. Ultimately, it’s subjective. A common limit-setting approach used in the US incorporates this subjectivity using the idea of the 85th percentile speed — the speed below which 85 percent of all drivers would choose to travel on a road. This criterion assumes drivers know what is reasonable and prudent and only adjusts the speed limit downward if “too many” accidents are occurring in the area. This approach has strong practical appeal because it means that most drivers will not be breaking the law if they drive as fast as they want. The problem with the 85th percentile rule is that it redefines the concept of the speed limit from a safe speed to the public consensus of a comfortable speed.

One of the underappreciated qualities of technology is that it insinuates itself into our lives making its existence seem natural. When the English Parliament created the first speed limit for mechanical-powered vehicles in 1861, 10 mph was set as the maximum speed limit. When this was deemed too fast, the law was amended to 4 mph outside towns and 2 mph in towns. As vehicles became more common and faster over the years, faster speeds became more familiar and thereby more acceptable. Now, any attempts to lower speed limits are largely maligned, often unenforced, and eventually rescinded — not because they generate no benefits, but because they are unpopular. A consensus approach to speed limits can create a dangerous feedback loop because risks become more acceptable as they becomes more familiar.

One could argue that it’s the few drivers who naturally like to drive too fast that are causing all the fatalities. However, according to a 2017 study by the National Transportation Safety Board, about one-third of all traffic fatalities are related to speeding. This indicates that speeds above the speed limit are clearly dangerous. However, another way to look at that statistic is that most fatalities occur in accidents at or below the speed limit. So if these speed limits are safe, then why are motor vehicles a leading cause of death for children?

A 2018 study by the International Traffic Safety Data and Analysis Group had similar findings regarding the danger of speed noting that for every one percent increase in speed, there was a four percent increase in fatal crash frequency. This is unsurprising because well-designed vehicles can only do so much to counteract the basic underlying physics. The damaging force on a crash victim is proportional to the speed of the vehicle divided by the time the vehicle comes to rest. Advanced crumple zones, air bags, and seat belts can decrease the force by spreading it over a larger time, but there are limits. It’s even worse for pedestrians. Ironically, driving a car is statistically safer than walking per mile traveled because most pedestrian fatalities are due to being struck by vehicles. For this reason, the 2018 study recommended reducing speed limits to 30km/h (<20 mph) in areas with pedestrians and 90 km/h (55 mph) on highways. It also endorsed the increased use of speed cameras which have improved speed limit compliance in Europe. Despite evidence of their effectiveness, speed cameras and red light cameras are actually prohibited in some US states because they are believed to infringe on constitutional rights (or at least the assumed American right to speed).

Autonomous bus, Rudolf Simon, 2018

Technology to the Rescue?

These three complementary explanations for our love of physical speed — utility, pleasure, and risk underestimation — together ensure that modern society embraces speed. This is why voluntary speed control does not work. Most people do not see it as a major problem and, even for those who do, the opportunity and temptation to travel at imprudently high speeds overwhelms any sensible impulses. Furthermore, speed limits are often based on public preferences rather than safety. So driving at the speed limit may be trading more safety for speed than you think.

The net result is that, as long as people are given control over their travel speed, they will probably travel too fast. The only way to break the cycle is to take the decision out of human hands. Speed control must be baked into the enabling technology. That means that the speed of any powered vehicle should be automatically controlled. This can be as simple as a maximum speed limiter which can be implemented on all powered transportation with negligible cost. However, modestly priced driver assistance technology exists today that allows vehicles to read and obey speed limit signs. To be clear, this is not a technological solution to a technological problem. Rather, it is using technology wisely to address an existing human behavioral problem that has been exacerbated by the unwise use of technology.

Autonomous vehicles can help eliminate speeding, but there is considerable disagreement regarding how soon fully autonomous driving technology will be available. There is also concern about autonomous driving ethics — the hard decisions a self-driving car would need to make in the case of an unavoidable accident. However, the underlying assumption is that autonomous cars will behave just like current vehicles in that they will frequently travel faster than they can safely stop. Rather than fret over “trolley problem” algorithms that must decide which pedestrians to run over, would it not be better to design cars that never speed beyond the capabilities of their braking system (and backup braking system!) in the first place? Once again, our love of speed prevents us from imagining that many “unavoidable” accidents could be avoided.

This is not just a future hypothetical situation. Partially automated driving in the form of active safety features is available now. It would be a small effort to adjust these capabilities to emphasize cautious speed control — like smart cruise control, but wiser. We can do much better with minimal effort if the public, policymakers, and technologists all agree to value life over speed.

Exploring the intersection of science, technology, and society • Dangerous Science ➜ https://doi.org/10.5334/bci

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