Taller Vehicles Kill More Pedestrians
It's not just a theoretical risk. The evidence is real
Yesterday, I wrote about my experiences driving an oversized (or, by contemporary American standards, a normal-sized) pickup truck. The thesis, if it wasn’t clear, was that these trucks shouldn’t be allowed to be part of our normal environments—but that they have an attraction to our sense of power and vanity that explain why these dangerous, oversized vehicles nevertheless have an appeal.
Two pieces, coincidentally, have appeared since then that warrant an unusual follow-up post.
The first is urbanist Addison Del Mastro’s reflections on why it might be individually rational to buy an SUV even though they’re socially suboptimal. Del Mastro’s piece is worth reading, as is his newsletter. Activists sometimes want everyone to stay on message but I think that an argument is stronger when you acknowledge contrary claims. And Del Mastro grapples with the contrary claim to my—our, mostly—position that these trucks are a menace to people:
The problem is not with cyclists, or anti-SUV people, nor is it with ordinary suburbanites and motorists who have never given more than five minutes’ thought to any of this. The problem is our culture of driving. Our motoring culture essentially encourages us—forces us—to hope that the other guy will die. It forces us to assent to the idea that mobility demands a price in blood. It is morally corrupting and rotten. The answer to so immense a collective problem must not be individual. We must agree, as a society, to root out whatever must be rooted out to end the carnage.
“Mobility demands a price in blood.” Powerful stuff! And I think he has got the idea exactly right: for a motorist, Del Mastro writes, a car-centric culture’s “death toll, in which he potentially participates every time he drives, [is] no more willed or chosen or preventable than a heart attack or a case of cancer.”
You can imagine, if you like, contemporary Americans as being some sort of distant civilization. It’s obvious from this remove that sacrificing more pedestrians to preserve someone’s ability to commute is a terrible policy outcome, but from inside that culture it is, almost literally, unquestionable. I mean, literally, just try to question it at a local planning meeting or when you meet the cost-benefit analyses that govern the siting and maintenance of road infrastructure: we don’t have the capacity to treat pedestrians as part of the traffic mix. They’re extraneous, even undesirable because they’re a threat to traffic.
(In this regard, it’s noxious that the CDC recommends that pedestrians keep themselves safe by “avoiding using electronic devices like earbuds” or “Increasing your visibility when walking at night by carrying a flashlight”. These are practical accommodations to a fallen world, to be sure, but they’re also ultimately a reminder that the government won’t protect you from the roads the government has built.)
Del Mastro’s reflections on the cruel logic of the externalities of SUVs points to a common implicit argument in the everyday practices of American consumers. Why take a risk by remaining bipedal or bicycling when you can encage yourself in an SUV? That logic only makes sense until you recall some clear counterarguments to that. For one, the best parts of America—our handful of real cities—are places meant for people, in which cars, especially big trucks, are an enemy intrusion. For another, we already sacrificed many cities to the car, meaning that the “choice” between walking and driving is one where the state has intervened, decisively and over decades, on behalf of cars. For a third, the cars currently on offer reflect a mix of policy choices, from low taxes on gasoline (too low to keep the roads repaired) to federal fuel efficiency standards that privilege big trucks (a grotesque outcome in an era of global warming.)
Finally, if the argument is that having a bigger vehicle than the other guy makes you safer, then truck and SUV sizes are an arms race, in which mutual—or forced—regulations to arrest vehicle sizes would improve everyone’s safety. It’s not freedom to be forced to choose ever-deadlier and costlier vehicles.
The second is an exciting article in Economics of Transportation by Justin Tyndall.1 Tyndall examines automobile crash data for 3,400 vehicle crashes in which a pedestrian was hit. He links vehicle data to include the dimensions of the cars involved, which allows him to estimate how the sizes of cars—in particular the height of their fronts—affect pedestrians.
Tyndall argues that a focus on vehicle weight may be misguided; even a large increase in vehicle mass won’t change the ratio of vehicle:human mass very much. Instead, the architecture of the vehicle matters:
Pedestrians may be particularly vulnerable to changing vehicle heights as the high front-ends of large vehicles mean the point of first contact in a collision with a pedestrian is more likely to be in the torso or head, rather than the legs. Vehicles with higher front-ends are also more likely to push the pedestrian under the vehicle rather than deflecting them onto the hood.
Among his new findings is the simplest: “larger vehicles are more likely to kill pedestrians, conditional on striking them”. The blunt data show that a full-size SUV is a little under twice as likely to kill a pedestrian as is a van, and 30 percent higher than a car. His statistical analysis shows that, holding speed and other factors constant, it is the front-end height of a vehicle, not its weight, that kills pedestrians. (And, yes, there’s a gendered aspect here, too: female pedestrians are substantially more likely to be killed.)
Using these results, Tyndall constructs a model to estimate how many people could be killed by rising vehicle heights. The statistics are stunning. Had the 1,026 pedestrians struck by compact SUVs been hit by a car instead, nearly 400 of them would have lived. Overall, rising vehicle heights may be responsible for roughly 1,000 excess pedestrian deaths.
One thousand people.
I’m just a poor country political scientist, but it sure seems like eventually the rising body count might warrant policymakers to inquire whether the auto industry might need to change how they do things. Tyndall’s analysis, in other words, supplies yet another piece of evidence calling for the dreaded regulation of automobiles in order to, literally, save lives.
Tyndall, Justin. 2024. “The effect of front-end vehicle height on pedestrian death risk.” Economics of Transportation 37.