Let’s Get Serious About Capping Car Speeds in Crowded Cities

There's no reason that cars in urban areas should be capable of traveling more than 20 mph.

Video still: WCBS
Video still: WCBS

Tuesday’s truck attack on the southern end of the West Side Greenway was hard to process. The harm was great — 8 people dead, about a dozen seriously injured. And the victims were assaulted in a place that’s supposed to be a refuge from the stress and aggression of typical city streets.

The West Side Greenway is where you go to breathe salty Hudson River air and watch the sun set over New Jersey. It’s the New York City bike path where cars intrude the least, where someone who’s not quite confident enough to brave the streets on a bike can find their legs. It’s the kind of place where you can let your guard down a little and relax the heightened sense of alertness you have to carry near motor traffic.

Saifullo Saipov violated that sense of security. And it’s infuriating to know that, like so much vehicular violence, his attack was preventable.

When I first heard that a truck driver had hit people on the greenway, I thought of Eric Ng. On December 1, 2006, Eric was struck and killed by Eugenio Cidron on the West Side Greenway. Cidron was driving drunk after a night out at Chelsea Piers and managed to travel a mile on what is supposed to be a car-free path. Afterward, Transportation Alternatives called for measures to prevent motorists from driving on the greenway.

To this day, however, many entry points to the greenway remain vulnerable to unauthorized motor vehicle access. Some posts that guard the greenway are flimsy and pose no physical obstacle to cars or trucks. They’re just suggestions. It’s a scandal that the agencies in charge of the greenway have let these vulnerabilities persist for years.

As more details emerged about the violence and it became clear that Saipov had acted with deliberate malice, sturdier bollards on the greenway still seemed necessary — but not nearly sufficient to prevent similar attacks. Stopping the next vehicle rammer — and NYC has already been victimized by two this year — is not something that street design alone can guarantee.

In New York, we should absolutely be designing safer greenways. We should be making more streets safely accessible to people walking or biking and off-limits to people in motor vehicles. We should be doing these things because space is precious and it makes no sense to let cars crowd out healthier, cheaper, more enjoyable ways to get around. But there are limits to car-free street networks as a preventive safety measure.

In a large, crowded city there will always be points in the transportation network where large numbers of people are exposed to the path of motor vehicles. Any crosswalk on a major Midtown avenue, for instance, is susceptible to people who want to do what Saifullo Saipov, Richard Rojas, and James Alex Fields have done, and bollards are not an option there.

The fundamental weakness that these attackers exploited is not the absence of physical barriers. It’s our willingness to allow vehicles capable of lethal speeds to occupy the same space as large numbers of unprotected human beings. We’ve grown acclimated to living in close proximity to vehicles that can be driven 70, 80 mph or faster, even though there’s no reason that cars in crowded cities should be capable of traveling more than 20 mph.

A ramming attack carried out at 20 mph is not going to cause great harm. A vehicle moving at 20 mph can more easily be evaded, and any impact is much less likely to be fatal.

If we address this vulnerability, not only would intentional vehicular attacks lose their destructive power, but the far, far larger number of traffic fatalities and injuries caused by ordinary negligence and recklessness would also plummet. The potential to prevent this routine violence and the staggering loss of life and limb it generates is the most compelling reason to cap car speeds.

To be clear, I’m not talking about lowering NYC’s default speed limit from 25 mph and adding a bunch of enforcement cameras. Those steps would save many lives (and we should pursue them vigorously!) but could still be circumvented by a motivated psychopath with car keys. What I mean is that except for emergency vehicles, cars and trucks should be programmed not to exceed 20 mph in urban areas.

Sound outlandish? The barriers are not as intimidating as they might seem.

Modern vehicles are already outfitted with computerized systems that limit maximum speeds. Right now they are blunt instruments, but making them responsive to urban contexts poses far fewer technological hurdles than producing autonomous vehicles, which the car industry is chasing with truckloads of R&D money. Compared to full autonomy, it would be a trivial matter to add a layer of geographical awareness so drivers are incapable of lethal speeds on city streets but free to go 65 on the highway.

Culture will be a bigger obstacle than technology. The ability to drive at dangerous speeds is zealously defended even in many parts of New York. The city’s 25 mph default speed limit (which in practice is not enforced unless you drive faster than 35 mph), set off bouts of whining from people accustomed to treating big streets that cut through neighborhoods as speedways.

Their arguments aren’t grounded in the genuine necessities of city life. Our surface mobility problems derive from congestion that slows cars and buses to a crawl, not the speed limit.

It’s one thing to make the case for capping city car speeds in a blog post, and another to campaign for it as a real change to the transportation system. Where would a campaign for 20 mph cars start?

The entry point, as I see it, is the sense of impending technological change generated by the recent drumbeat for autonomous cars. Whether or not you believe the claims about autonomous vehicles hitting the market in a few years (I think it’s going to take longer than that), the industry is spending big on AV technologies, lobbying hard for access to streets to test AV prototypes, and hyping the potential benefits, including safety gains.

It’s hard to game out how this will all unfold when there’s still so much uncertainty about the trajectory of the technology. So instead of worrying about the end-state of AVs, why not begin with a discrete, manageable step, based on components of the AV package that are clearly viable?

The transition to 20 mph cars in cities would be far simpler than any hypothetical transition to all-out autonomy, while delivering huge public safety benefits. We can live in cities where cars don’t travel at lethal speeds. In fact, we should insist on it.