Don’t expect your car’s safety technology to save you

Car companies love to explain how their research and development efforts will lead us toward “a world with zero crashes,” as General Motors puts it. Automakers like Stellantis and Nissan, among others, tout their efforts to develop “next generation technologies to make roads safer for drivers and pedestrians alike.” 

With American roadway deaths now exceeding 40,000 per year — including a surge of 10.5 percent in 2021, the fastest on record — these promises sound like salvation. 

The companies are referring to technologies, typically known as advanced driver-assistance systems (ADAS), that can manage aspects of the driving experience and intervene if the human behind the wheel makes a mistake. Such features include automatic emergency braking, lane keep assist, adaptive cruise control, and pedestrian detection. With billions of dollars invested, automakers, federal regulators, and safety advocates alike are bullish about ADAS’s potential to achieve “collision-free mobility,” as Honda puts it. 

But upon examination, these new features are hardly the panacea that their boosters imply. Some elements presented as safety enhancements (like lane keep assist) may be little more than driver conveniences. For now, at least, those technologies that could save the most lives (like pedestrian detection) remain deeply unreliable. And even if ADAS eventually works flawlessly, it is likely to have only a modest impact on annual traffic deaths. 

As the United States confronts a national crisis of traffic fatalities, carmakers and policymakers alike are focused on unproven and overhyped innovations. In reality, even the best technologies can’t compensate for the ways in which ill-conceived cars and poor street designs have made crashes more numerous and severe. We risk making our road safety crisis even worse by expecting car tech to bail us out. 

The core concept behind ADAS involves leveraging computer power to handle aspects of driving traditionally managed by a human — something that will be familiar to anyone who has used cruise control to make long highway trips a little less tedious. 

Over the last two decades, automakers have developed numerous features that deeply integrate technology into the act of driving, capitalizing on powerful sensors and cameras embedded in new vehicles. Some of these features, like pedestrian detection and automatic emergency braking, are intended for use only to prevent an imminent collision. Others, like lane keep assist and adaptive cruise control, can “ease the burden” of driving, as JD Power put it, by ensuring that the vehicle keeps pace with surrounding traffic and stays within its allotted road space. 

Products like Tesla Autopilot or Ford BlueCruise integrate these individual features into a multilayered system that can fully operate the vehicle on a highway — provided that the driver stands ready to take control if needed. That assumption is critical because these systems are not smart enough to manage a vehicle on their own. 

To ensure the driver stays focused, carmakers rely on driver monitoring systems designed to keep an eye on the tilt of a person’s face or their grip on the steering wheel. Should the driver’s attention wander, driver monitoring systems will issue a warning before ultimately forcing the driver to retake control of the vehicle.  

Industry groups sometimes call ADAS “partial automation,” a term intended to signify that, advanced as these systems are, they do not enable a car to become autonomous.

Although Elon Musk has claimed that Tesla’s Autopilot ADAS system could save half a million lives if universally deployed, there is scant evidence supporting that claim (or others about ADAS’s supposed safety benefits). The US Department of Transportation recently began collecting data about ADAS-related crashes, but it’s too soon to draw many insights.

David Harkey, the head of the Insurance Institute for Highway Safety (IIHS), is not impressed by what he has seen so far. “Partial automation systems may make long drives seem like less of a burden, but there is no evidence that they make driving safer,” he said in an IIHS blog post. “In fact, the opposite may be the case if systems lack adequate safeguards,” a reference to those all-important driver monitoring systems. 

Nevertheless, many car regulators and safety advocates are enthralled by ADAS’s potential to reduce crashes. In 2016, Mark Rosekind, then the head of the federal National Highway Traffic Safety Administration (NHTSA), extolled “technologies that promise a revolution in safety unlike any in the history of the automobile” (a quote that the Alliance for Automotive Innovation, the largest US carmaker association, places on its webpage). Cathy Chase, the president of Advocates for Highway and Auto Safety, said that “the universal adoption of these technologies will literally save tens of thousands of lives” in a 2021 letter to US Transportation Secretary Pete Buttigieg. 

But for the moment, ADAS remains very much a work in progress. A 2020 study by AAA found that the average system turned itself off every eight minutes, noting “instances of trouble with the systems keeping the vehicles … in their lane and coming too close to other vehicles or guardrails.” In a separate study of pedestrian detection, AAA found the feature to be “completely useless” at night, when 75 percent of pedestrians are struck. The European Transport Safety Council concurred, noting ADAS’s shortcomings in dark, wet, or foggy conditions. Even more troubling, automakers’ crucial driver monitoring systems can be cheated and do not work reliably. 

All of that being said, ADAS performance will likely improve due to the billions that carmakers are investing in its development, along with insights gleaned from reams of data collected from cars using these systems on the road. But even if the technology ultimately functions as intended, it may have only a marginal impact on the US roadway death toll.

Consider the need for a human to remain ready and able to take over the vehicle. Even if driver monitoring systems prevent a driver’s attention from wandering, what happens if road skills atrophy from lack of use? This is more than a theoretical issue; a study of truck drivers recently found that automated driving technology led to slower reaction times, and a report from the US Department of Transportation Inspector General raised concerns that automation could be degrading the skills of commercial pilots. 

Worse, those focused on ADAS’s technical capabilities risk overlooking its potential to encourage riskier driving. In 1975, Sam Peltzman wrote a seminal economics article examining the safety effects of state seat belt laws. Peltzman concluded that the mandated use of seat belts led drivers — secure in the straps across their waists — to take more risks behind the wheel, leading to injuries and deaths that negated those saved by the belts themselves. In effect, he argued that the new feature’s benefit was negated by behavioral adaptation. 

Today, the “Peltzman effect” explains why safety technologies in fields including healthcare and sports cause people to adopt riskier behavior. Applied to ADAS, the Peltzman effect predicts that drivers will become less careful, trusting the vehicle’s technology to protect them. But ADAS is not a fail-safe; physics limits its ability to abruptly halt a vehicle. For example, Mercedes claims that its system can prevent pedestrian collisions at up to 30mph and mitigate the severity of vehicular crashes at up to 45mph, but the company makes no promises above those thresholds. This isn’t a challenge limited to Mercedes: a recent AAA study found that carmakers’ automatic emergency braking systems prevented 85 percent of test crashes at 30mph but only 30 percent at 40mph. 

Already, a study by the IIHS found that the use of adaptive cruise control increased the share of drivers who broke the speed limit by 18 percent, and San Jose State researchers concluded that ADAS-equipped cars were more likely to crash into pedestrians or cyclists. These findings align with the Peltzman effect’s predicted shift toward unsafe driving, with those outside the vehicle bearing disproportionate risk. Such dangers could be exacerbated by drivers who overestimate ADAS’s capabilities, as more than half of Cadillac Super Cruise users seem to do, according to a recent IIHS study.

There is another reason these innovations could invite more roadway deaths, something both fundamental and easily overlooked. To understand it, note that Hyundai acknowledges on its website that “ADAS is not just about safety; it’s about providing convenience as well.” Indeed, features like adaptive cruise control and lane change assistance are largely intended to make driving more pleasant rather than to minimize crashes. 

How do people respond when an activity becomes easier or more enjoyable? They do more of it.

Just as comforts like air conditioning and radios induced car owners to drive more, the comforts of software-assisted driving will compel them to take additional trips and travel further (which may contribute to automakers’ excitement about it). One study has already found that Tesla owners using Autopilot drove about 5,000 more miles per year than those without it. All else being equal, additional miles driven bring additional chances to crash. 

ADAS’s overall effect on road deaths becomes murky when these countervailing forces are considered alongside its technological potential. The systems may prevent certain collisions that would have otherwise occurred while at the same time leading to a degradation of driver skills, riskier behavior behind the wheel, and a surge in total miles driven.

We can debate whether the overall effect on roadway deaths will be positive or negative, but those expecting a virtual elimination of crashes are likely to be sorely disappointed.

The good news is that if public officials are serious about reducing road deaths, there are plenty of compelling approaches that have nothing to do with technology, such as designing streets for slower speeds, building dedicated bike lanes and sidewalks, and ramping up transit service to entice people to switch from cars. (Riding in a bus or a train is orders of magnitude safer than being inside a motor vehicle.) Keeping habitually reckless drivers off the road would also be a significant step forward. 

Rather than placing so many eggs in the ADAS basket, regulators and automakers’ R&D teams could focus on other ways that safer car designs could reduce road deaths. Speeding, tied to some 11,000 deaths per year in the United States, could be curtailed with intelligent speed assist, which automatically warns or slows drivers who are exceeding the speed limit. Europe has already moved to require intelligent speed assist in passenger vehicles, but so far, Congress and the National Highway Traffic Safety Administration have shown no signs of following suit. (Among automakers, only Volvo has voluntarily installed the feature.) 

Automakers could also confront ways in which their previous design decisions have worsened America’s road safety crisis. For instance, car companies have sought to replicate the smartphone experience by replacing dashboard knobs with infotainment touchscreens. Regardless of whether you like car touchscreens (and many people don’t), the absence of tactile feedback forces drivers to look away from the road — something that is inherently dangerous when a multiton hunk of metal is hurtling down a road at 50mph. Research from Drexel University shows a growing number of crashes tied to infotainment, but so far, NHTSA has done nothing beyond issuing voluntary guidance (which carmakers have routinely violated) about the maximum amount of time it should take to complete a task on an infotainment system. 

Meanwhile, automakers have added girth to their SUVs and trucks, which now dominate the American car market (together representing over 80 percent of sales). A taller, heavier vehicle is more likely to injure or kill in a collision, especially when striking a pedestrian or cyclist. Acknowledging this risk, auto regulators in Europe, Japan, and Australia have incorporated pedestrian crashworthiness into their car safety ratings, known as the New Car Assessment Program, or NCAP. But the United States has not. 

Earlier this year, NHTSA announced a long-awaited update to the American version of NCAP, including a proposal to finally address risks borne by vulnerable road users. But rather than examining pedestrian crashworthiness, the agency chose only to evaluate ADAS’s pedestrian detection technology. In a press release, the agency credited itself with a “novel approach to tie technological change to reducing driver behaviors that contribute to many crashes.” The dangers of oversize SUVs and trucks were not mentioned. 

NHTSA’s focus on ADAS instead of SUV and truck bloat likely came as a relief to automakers who make fat profits from the sales of huge, pricey vehicles. Rather than discuss how their past choices have contributed to America’s burgeoning roadway death toll, they would prefer to paint a utopian picture of universally safe driving at some point in the future, once ADAS is perfected and widespread. 

Case in point: the NBC affiliate in the Washington, DC, region recently produced a segment exploring SUV “blind zones” that can make a child in front of the vehicle invisible to the driver. Asked for comment, the Alliance for Automotive Innovation, a carmaker industry group, tried to shift the focus away from dangerous SUV design and toward the promise of innovation. A spokesperson said that “vehicles continue to get safer as automakers across the board test, develop, and integrate new technologies that can save lives.”

That answer, of course, is a deflection. 

Lucas Peilert contributed research assistance to this article.