Some causes of death have little trouble catching the public’s attention. Avian flu, Ebola, and Zika have dominated news cycles and prompted international travel advisories. Plane crashes interrupt broadcasts and lead to thorough government investigations. Cancer, heart disease, and HIV/AIDS now attract billions of dollars of research. But one of the biggest killers of all gets little attention from governments, the media, or the general public. Car crashes killed 1.35 million people in 2016—the last year for which World Health Organization data are available—a grisly 3,698 deaths a day. Traffic injuries are now the top killer of people aged five to 29 globally, outpacing any illness and exceeding the combined annual casualties of all of the world’s armed conflicts. And the toll continues to rise: it grew by 100,000 in just three years, from 2013 to 2016. This does not include the up to 50 million people who are hit and injured by motor vehicles each year, some grievously, but who nonetheless survive. The economic losses are estimated at three percent of global GDP.

In many high-income countries, the per capita traffic death rate has dropped over the last 50 years, in part thanks to advances in car safety and stricter drunk-driving laws. In the United States, traffic fatalities have fallen by nearly a third since the middle of the twentieth century. But even so, 36,560 Americans died in car crashes in 2018—about as many as were killed by guns. Moreover, the news is getting worse for people not in a vehicle. In 2018, the number of Americans killed by cars while walking or riding a bike reached 7,140—the highest since 1990, according to the National Highway Traffic Safety Administration, and a 41 percent increase since 2008.

Globally, the absolute number of traffic deaths has crept upward as ever-greater numbers of people make more trips. Low-income countries, with lax safety standards and poorly designed roads, fare the worst: they boast just one percent of the world’s motor vehicles but suffer 13 percent of total traffic deaths. Ethiopia, for instance, had 26.7 traffic deaths per 100,000 residents in 2016, almost ten times the rate in Sweden and double that in the United States.

To the extent that policymakers have reacted to this crisis, they have tended to do so through incremental measures: passing universal seat-belt laws, mandating air bags and antilock brakes, lowering speed limits, and raising penalties for drunk driving. These are valuable steps, but they are nowhere near enough. That’s because the root cause of traffic danger isn’t defective cars or unruly drivers. It’s the roads themselves.


At the turn of the twentieth century, city streets were largely shared spaces, where people on foot mixed in the street with vendors, streetcars, cyclists, and carriages. The arrival of the motor vehicle was initially viewed with horror, as U.S. traffic deaths climbed from just 26 in 1899 to 29,592 in 1929. To increase speed and safety, streets were widened and cleared of obstacles. Engineers and public officials jammed multilane roads, highways, and bridges into previously quiet neighborhoods in order to move as many cars as quickly as possible through cities. Many cities didn’t even bother to build new sidewalks since destinations were so far away from one another that it was not feasible to walk. When the widened roads became just as congested and dangerous as the ones they replaced, engineers responded with still more construction, turning streets into automotive monocultures, where the mere idea of walking, biking, or taking public transit was viewed as foolish. But the multilane roads did not solve traffic congestion; they only enabled more and more drivers to take to the streets. In 1955, the urbanist Lewis Mumford noted that widening roads to solve traffic congestion was like loosening one’s belt to solve obesity—it temporarily eased constraints but did not solve the underlying problem.

The result of a century of car-focused design is that on every continent, roads and lanes tend to be wider than is necessary or safe. Although this keeps cars farther apart, bigger lanes—usually around 12 feet wide—reduce what traffic planners call “friction,” a healthy interaction among drivers, pedestrians, cyclists, and others that induces safer behavior. Inevitably, roads designed for speed are deadlier. Psychology plays a role—oversize lanes encourage drivers to drive at dangerous speeds and to view everyone else on the street as obstacles—but so does physics. A pedestrian struck by a car moving at 25 miles per hour has a 90 percent chance of surviving. If that car is moving at 40 miles per hour, the odds drop to 50 percent.

Widening roads to solve congestion is like loosening one’s belt to solve obesity.

Compare the traffic death statistics for four sprawling cities—Charlotte, Dallas, Jacksonville, and Phoenix—to those for New York City. Although New York City’s traffic-choked streets might not seem safe, its pedestrian death rate in 2017 was no more than a third of that in each of those cities, and the overall traffic death rate was a mere fifth. That’s not because the residents of those cities are worse drivers but because those cities’ roads were built for fast driving and without safeguards for pedestrians.

In the United States, federal and state street-design guidelines explicitly promote wider lanes, even though they are known to be deadlier. In other words, far from being “accidents”—and indeed, the World Health Organization and other traffic-safety proponents have shunned that term—traffic deaths are caused by roads that are operating exactly as designed.

Traffic segregation is another principle that dominated twentieth-century road design, to the detriment of safety. The idea is that pedestrians (and everyone else) should be kept safely out of drivers’ ways. In London and Tokyo, pedestrian fences force the walking public onto the sidewalk. Meanwhile, Hong Kong posts bright blue signs: “Beware of Traffic.” But segregation isn’t always possible. Streets throughout Africa, the Americas, and Asia have poor or no sidewalks. Many cities in the developing world have seen pedestrian spaces taken over by parked cars, motorcycles, and vendors, forcing people to walk into the street.

Even though the root of the problem is the way the streets were designed, the trend has been to blame the victim. In many places, news reports of crashes tend to repeat claims (often dubious) that injured pedestrians or cyclists were distracted, delinquent, or insufficiently visible. In 2017, Honolulu criminalized texting while walking across the street despite having no evidence that it was a serious safety issue. Other American cities, such as Salt Lake City, implore pedestrians to carry high-visibility flags when crossing the street.

Cyclists (with and without helmets) in Copenhagen, March 2007
Anders Birch / laif / Redux

In cities as different as Chicago and Los Angeles, there is frequent talk of licensing bike riders or requiring them to wear bike helmets. Although bike helmets are a reasonable precaution, legally requiring them for all riders only reduces the number of cyclists on the street and thus the traffic-calming effect that they bring. In many Australian cities, for example, helmet laws have not lowered traffic deaths; instead, they have merely hobbled public bike-share systems, whose riders don’t want to carry a helmet wherever they go. Helmets aren’t what make biking safer. There are no helmet requirements in Denmark, the Netherlands, or Norway—countries where bikes are widely used for transportation and that nonetheless report fewer bike deaths per mile ridden than the United States.

As well meaning as most traffic-safety laws tend to be, they aren’t enough. Many societies have already had a century of practice training better drivers and writing better safety laws. Despite the laws on the books, vast numbers of crashes involve excessive speed, a failure to yield to pedestrians in crosswalks, or drinking and drug use. In 2017, 29 percent of traffic deaths on American roads involved alcohol. An estimated ten percent of crashes involved distracted drivers, many of whom were using cell phones. Instead of trying to legislate safety, a more effective approach is to design it.


The process can and should begin in cities. Although a 2018 study of 26 countries by the International Transport Forum found that most traffic deaths occur in rural areas, where speeding is common and where there is no space on the road for pedestrians, cyclists, or motorcyclists, the pattern is shifting as urbanization continues across the world. (By 2050, city dwellers are expected to compose 68 percent of the global population.) In city after city, a new generation of urban planners is finding new ways to reduce traffic deaths by retrofitting roads, sometimes dramatically.

Although the average transportation agency confines itself to repairing potholes, repaving roads, maintaining signs, and so on, there is much more that municipal governments can do. From 2007 to 2013, both of us worked in the New York City Department of Transportation under Mayor Michael Bloomberg. Our approach to traffic safety was simple and cost effective. Instead of dreaming up megaprojects, we took a long, hard look at the streets we already had, this time from the perspective of the most vulnerable people.

Between 2007 and 2013, the Department of Transportation redesigned lengthy portions of 137 streets and revamped 113 intersections—expanding the space to walk, decreasing crossing distances for pedestrians, and making streets navigable enough for children, senior citizens, and people with physical disabilities to cross. By narrowing lanes and putting drivers in closer contact with pedestrians and cyclists, the redesigns forced drivers to proceed, turn, and change lanes more slowly and predictably. We also collaborated with the New York City Police Department to implement reduced speed limits, using cameras to catch cars speeding, running red lights, or intruding in bus lanes.

As a result of Mayor Bloomberg’s redesigns, New York City saw a 37 percent drop in pedestrian deaths.

What’s more, we converted 180 acres of New York City road space into bike lanes, bus lanes, and new pedestrian space. This included making 2.5 acres in Times Square car free: Broadway was transformed from a taxi-choked corridor into a walkable haven. Instead of being forced by crowds to venture into the street, pedestrians now amble through the iconic destination at their leisure. We also introduced the first parking-protected bike lanes in the United States. In many cities, if a bike lane even exists, it is sandwiched between a lane of parked cars and a lane of moving traffic. Parking-protected bike lanes, by contrast, run alongside the curb and push the parking zone for cars a full lane into the street. This means cyclists don’t have to ride within arm’s reach of passing cars.

The results were visible in every borough—in the crowded avenues of Manhattan, the residential side streets of Brooklyn, the commercial centers of Queens, and the busy boulevards of the Bronx and Staten Island, many of which hadn’t changed in generations. From 2001 to 2019, traffic deaths along all of New York City’s 6,000 miles of roadway dropped by over 44 percent—from 394 to just 219—even as the number of pedestrians on the city’s streets increased and bike ridership tripled. The city saw a 37 percent drop in pedestrian deaths and similar reductions for those injured in a car.

This people-focused strategy has worked for some of the world’s most unforgiving streets, including in several cities where we worked with Bloomberg Associates and the Global Designing Cities Initiative to apply many of the designs pioneered in New York City. Mexico City was once one of the world’s most dangerous cities, with some 1,000 traffic deaths a year. But between 2015 and 2017, Mayor Miguel Ángel Mancera had 171 intersections redesigned so that there were clearly defined lanes, pedestrian medians, and crosswalks. He also reduced the citywide speed limit and ramped up traffic enforcement by using speed cameras. The redesigns helped lead to an 18 percent reduction in traffic deaths, including a 24 percent drop in pedestrian deaths. The number of bike riders killed fell by 78 percent.

A family-friendly bike lane in New York City, July 2017
A family-friendly bike lane in New York City, July 2017
Justin Gilliland / The New York Times / Redux

Halfway around the world, in Addis Ababa, Ethiopia, officials introduced shortened crosswalks for pedestrians at a busy intersection in the city center, modifications that made it easier to cross the street while also forcing vehicles to slow down significantly in order to turn. The number of serious injuries fell by half in the six months after the project, and the number of deaths went down from one before the change to zero after.

In Mumbai in 2017, a traffic-safety project at the menacing Mithchowki intersection reclaimed 17,760 square feet of roadway from cars and redesigned them for crowds of pedestrians. Using brightly painted movable barriers, a road-safety team created safe waiting spaces and simplified the process of crossing the street. After the modifications, officials noticed a 53 percent increase in sidewalk use. More important, 81 percent of people surveyed said they felt safer at the location as a result of the project.

Similarly, between 2018 and 2020, Milan under Mayor Giuseppe Sala transformed ten squares that were once clogged with parked cars into community-friendly spaces, with benches, tables, and planters. Where cars once roamed, children now play ping pong and neighbors greet one another.

Most of the time, urban planners do not have to reinvent the wheel. They have the experience and testimony of others to draw on. For instance, the Global Street Design Guide synthesizes the real-world experience and practices of experts from 72 cities spanning 42 countries. The guide has now been adopted by 100 cities and several nongovernmental organizations focused on traffic safety. It represents a sea change for street design, putting pedestrians and cyclists, rather than freight and private vehicles, at the top of the street hierarchy.

Often, all it takes to make streets safer is paint, planters, and basic materials already in stock in city depots, such as stones, signs, and flexible traffic posts. Even so, given the scale of the changes, municipal governments will require sustained investment to expand on these proven safety practices and turn the tide on traffic deaths.


If low-tech solutions can have such a tremendous impact on human health, what about high-end technologies? The driverless-car industry contends that it is at the forefront of the traffic-safety charge—promising that autonomous vehicles could be programmed to maintain safe speeds no matter the environment. They point out that a combination of GPS data and sign-recognition cameras in cars can limit a vehicle to the posted or official speed limits.

It’s all well and good to claim that driverless cars operating in a closed, connected system would be safer. But everything is different on the open road, where those cars would need to drive alongside hundreds of millions of human-driven vehicles, whose operators are still speeding, cutting one another off, and jockeying for position. There has been only one death involving an autonomous car, but even one death doesn’t speak well of the technology’s capabilities in city centers alive with thousands of human actors—a jumble of people walking, biking, making deliveries, panhandling, and so on.

A self-driving car in London, March 2017
A self-driving car in London, March 2017
Evening Standard / eyevine / Redux)

Transportation officials can’t wait for driverless cars to make streets safe. Sidewalks won’t extend themselves; crosswalks won’t magically appear. Countries can’t bet their futures on the promise that better cars or better drivers will reverse the damage caused by a century of car-obsessed roadway design. If cities want infrastructure that accommodates all users, they need to lead by example and reclaim, redesign, and reconstruct their roads.

Government and public health officials routinely face problems that exceed their capacities and powers. Traffic deaths are not one of them. Indeed, traffic-related fatalities are unusual in that their causes are as straightforward as their solutions. Eliminating most health hazards on the roadway doesn’t require new technologies or unsustainable investments. It requires changing how we view traffic deaths and injuries, treating them as avoidable byproducts of a crisis in urban design rather than an inevitable feature of modern life. There is already a revolution underway to redesign city streets to a new standard. But there is still much work to be done and a growing population that needs protection.

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  • JANETTE SADIK-KHAN is a Principal at Bloomberg Associates. From 2007 to 2013, she was Commissioner of the New York City Department of Transportation.
  • SETH SOLOMONOW is a Manager at Bloomberg Associates. From 2007 to 2013, he was Deputy Commissioner for External Affairs at the New York City Department of Transportation.
  • They are the authors of Streetfight: Handbook for an Urban Revolution.
  • More By Janette Sadik-Khan
  • More By Seth Solomonow