Are Large Cars Safer Than Small Cars? Not Necessarily, Study Finds

But it only works if everyone downsizes together.

For decades, people have maintained the belief that when it comes to automobiles, bigger may not be better, but it is safer. In the event of an accident, this line of reasoning goes, it’s best to be surrounded by as much metal and plastic as possible. Can’t argue with physics, right?

Some people have used this logic to argue against governmental fuel economy standards, which can encourage automakers to develop smaller vehicles in order to boost their fleet gas mileage averages. After all, the more mass you have to soak up the force of an impact, the more energy the engine has to create to overcome the vehicle’s inertia—and the more energy it makes, the more fuel it burns. Like we said—can’t argue with physics. 

So are eco-friendly measures like the Corporate Average Fuel Economy (CAFE) standards causing more deaths? Well, according to a study conducted by the National Bureau of Economic Research released last month…no. In fact, according to researchers, downsizing the cars on the road seems to actually 

As the study points out, the problem isn’t one of size—it’s a matter of the size differential. When a small car hits a large car, the small car gets the bad end of the deal not because it’s inherently small; rather, it gets mangled because it’s so much smaller relative to its co-impactor. (A 2005 Crown Victoria that hits a Pinto weighs just as much as a 2005 Crown Victoria that slams into a Hummer H1, but everything else being equal, those impacts will work out a helluva lot better for the folks in the first Crown Vic.) Measures like CAFE force all the cars on the road to get smaller, however, not just the already-small ones. 

“What CAFE actually does is it doesn’t just lower the weight of one vehicle,” co-author Kevin Roth said, according to The Washington Post. “It changes the entire composition of the fleet.”

For the study, the researchers collected data on a stunning 17 million car crashes that occurred between 1989 and 2005, then simulated how those crashes would likely have gone down if not for CAFE. Remarkably, they found that between 171 and 439 fewer deaths occurred each year in the real world than likely would have in a reality where CAFE never existed.

The study could prove prescient should the Trump administration choose to flush some or all of the Obama administration’s planned CAFE enhancements down the toilet—or doubly so if the current occupant of the White House decided to dump the entire federal guideline.