The Growing Threat of Oversized Vehicles to Pedestrian Safety
The number of pedestrian deaths in the United States has alarmingly increased. In 2022, traffic incidents took the lives of 7,805 people on foot—an 83 percent jump from 2009, marking a 40-year high. The vast majority of these fatalities involved a vehicle colliding with a pedestrian. A critical step toward tackling this rise of ‘killer cars’ was recently taken by the National Highway Traffic Safety Administration (NHTSA), with the proposal of a new federal regulation. This rule would mandate—not just suggest—that automakers make sure the front ends of their vehicles don’t pose excessive risk of head injuries to pedestrians.
Should the proposal become law, larger SUVs and pickups would face particular challenges in passing NHTSA’s mandatory tests. Some cars would need to be scaled back in size. This would not completely solve the problem of how large cars have become; the head is only one part of the body that can be injured by a vehicle. But it is a significant moment for the NHTSA, marking the agency’s first demand that automakers adjust the physical design of their vehicles to safeguard those on foot. Currently, the NHTSA is seeking public feedback, with the general public and automakers able to contribute to whether the rule becomes law or is diluted.
The country is at an important juncture, where it can finally begin to solve the deadly problem of large cars – or allow it to worsen.
Auto executives usually acknowledge the role of their products in the pedestrian safety crisis, but they propose a very different approach. Instead of directly addressing vehicle size, they emphasize emerging technologies like pedestrian automatic emergency braking, which could potentially avoid crashes entirely, thereby negating the dangers that larger vehicles present in a collision. However, these technologies are not consistently effective, and even in the future, their benefits will be limited. Addressing the harms of gigantic SUVs and pickups would require stopping their production.
The Issue of ‘Car Bloat’
By ‘car bloat,’ I mean the continuous expansion of vehicle sizes over the past 50 years. While this is globally present, it is particularly evident in the United States. Sedans and station wagons have been largely replaced by SUVs and pickups, accounting for about four out of five new car purchases. At the same time, the individual models have become heavier. For instance, a 2024 Chevrolet Silverado pickup is roughly 700 pounds heavier and 2 inches taller than its 1995 counterpart. According to federal data, the average new American car now weighs approximately 30 percent more than it did 40 years ago.
‘Car bloat’ produces many “negative externalities,” as economists call them, which are costs borne by society and not purchasers. These include increased emissions, faster road deterioration, and decreased curbside parking capacity. However, ‘car bloat’s’ most immediate and critical downside is the danger it poses to anyone on the road not inside an oversized vehicle. Although those in larger cars may be slightly safer in a crash, those in smaller cars are at a much higher risk. In a crash, among the heaviest one percent of American cars, a recent analysis by The Economist found that 12 people die inside of smaller models for each person saved by their size.
The Risks for Pedestrians
Pedestrians are even more at risk. Research by the Insurance Institute for Highway Safety found that vehicles with tall, flat front ends, which are common on SUVs and pickups, are over 40 percent more likely to kill a pedestrian in a crash than those with shorter, sloped ones. Furthermore, large cars are more likely to hit someone in the first place because drivers sitting at a higher level off the ground have obstructed views of their surroundings. A 2022 IIHS study found that large vehicles’ A-pillars (the structure between the windshield and side window) often obscure pedestrians at intersections, and TV news stories have run segments showing that an SUV driver cannot see as many as nine toddlers sitting in a row in front of them.
The Industry Response
The most simple way to alleviate pedestrian safety risks would be to shrink the size of the largest car models; however, American automakers are hesitant to do so since big SUVs and trucks are highly profitable. Instead, the companies have turned to technologies that supposedly mitigate ‘car bloat’s’ safety issues. Executives often mention pedestrian automatic emergency braking, systems that use computer vision, lidar, or radar to identify a person ahead and stop the vehicle, thus preventing a crash. Earlier this year, the NHTSA finalized rules that will establish benchmarks for pedestrian automatic emergency braking (PAEB) on new cars starting in 2029. When the NHTSA announced its new proposal to lower the risk of pedestrian head injuries in a collision, the Alliance for Automotive Innovation, a trade group, mentioned PAEB in its response, implying that further regulations might be unnecessary.
Limitations of Advanced Technologies
While PAEB has real benefits, such as another 2022 study by IIHS finding that PAEB could prevent about a quarter of pedestrian deaths, the same study also found that carmakers’s PAEB systems did not perform reliably in turns or at night when about 3/4 of pedestrian deaths occur. A study released earlier this year by Missy Cummings, a robotics professor at George Mason University and a former NHTSA advisor, assessed six vehicles’ PAEB systems and concluded that the cars “were not consistent internally or with one another in pedestrian detection and response.”
Cummings stated that these results did not surprise her. “PAEBs can detect pedestrians in some conditions, but, because of their architecture, they inevitably cannot work 100 percent of the time,” she said. “Radar requires movement, so if it’s seeing something move, it can do a good job. Lidar requires dry weather, so if it has that, it does a great job.” She paused before judging computer vision, the main technology in Tesla’s automatic braking systems: “It never does a good job.”
Automakers appear to acknowledge the limitations of these pedestrian detection systems. Chevrolet’s PAEB webpage states that the technology may not detect children, people walking at night, or those who are part of a group. Car companies are also attempting to improve their PAEB systems before the NHTSA’s 2029 deadline. However, even if these systems eventually work flawlessly, the limits of physics will keep them from stopping a fast-moving vehicle in time to avoid colliding with a pedestrian.
The NHTSA’s 2029 PAEB standard will require cars to avoid collisions at 37 mph, but it does not set the same expectation if the car is traveling faster. By the agency’s own estimates, roughly half of all pedestrian deaths occur on roads with speed limits of 45 mph or higher. Therefore, PAEB is far from a pedestrian-safety panacea. The same goes for another technology that some, including Democratic Connecticut Senator Richard Blumenthal, have suggested could counter the hazards of car bloat: front and rear cameras that provide drivers with a picture of what lies ahead of or behind them. Although these cameras can help drivers see areas that would otherwise be obscured due to their vehicle’s height and hood design, they cannot provide unrestricted vision. “Blind-spot cameras still have blind spots,” said Cummings. “You still get that visual cone, and you’re still going to get things that are not in view.” Research has shown that people react faster to objects viewed directly rather than through a reflection or screen, indicating that drivers may need more time to react when observing an emergency through a camera than they would if seeing it directly.
Historically, the U.S. has considered street safety to be a problem that technology can fix without requiring changes to the size and shape of even the largest vehicles. Therefore, the actions of the NHTSA in requiring automakers to ensure their hood designs do not pose excessive risk of pedestrian head injury is significant. Future rules, including those on pedestrian torso impacts and cyclist crashes, could also be considered. The agency is finally acknowledging that automakers cannot simply innovate their way out of their responsibility to address the crisis of U.S. road safety. Regulating vehicle size directly is just as appropriate as it is necessary.
