Americans bought 15.6 million new vehicles last year, a 12% increase from 2022 and the biggest bump in more than a decade. And if you’ve noticed, many new cars on the roads are bigger these days. For example, the 2023 model of Ford’s F-150 truck weighs about 800 pounds more than the 1991 version. This market-driven phenomenon of cars getting larger and heavier is called car bloat, and the environmental and safety costs that come with it can be substantial.

“For decades, people who buy enormous, very heavy cars have been creating societal costs that they aren’t paying for. That’s what’s called a market failure,” said David Zipper, senior fellow at the MIT Mobility Initiative. “So if you want the market for automobiles to succeed, we need to make sure that when people are shopping for their next car, they are considering the societal costs of their purchase, which is going to be a lot greater if they’re going to be buying a very large model.”

“Marketplace” host Kai Ryssdal spoke with Zipper about his article about car bloat in Slate. Below is an edited transcript of their conversation.

Kai Ryssdal: Is there a moment you can point to in the long history of the American automobile industry where we turn the corner and car bloat sort of started happening?

David Zipper: Yeah, I would say that it’s probably in the late 1970s, when a sort of now forgotten company called AMC repositioned the Jeep, the old military vehicle, to be a modern SUV for suburban and urban shoppers. And, you know, fast-forward and SUVs are the most popular vehicle type today.

Ryssdal: And there’s a classification thing too, right? Because the government says, you know, they’re kinda like driving passengers around, but we’re going to classify them differently.

Zipper: That’s exactly right. The federal government, at the prompting of companies like AMC that were looking to sell SUVs, decided to classify SUVs as light trucks, which would have more relaxed fuel-economy standards than passenger vehicles like sedans and station wagons. And it paved the way to really where we are now, where 80%-plus of the new car market today is comprised of SUVs and pickups.

Ryssdal: So, let’s get down then to the brass tacks and why we wanted to talk to you. There are ramifications and a real-world impact of car bloat, and you tick through a couple of them in the piece. The first one that I want to touch on is safety. These cars are bigger and heavier. And if you get in an accident, and you’re on the other end of it, it is not going to end well.

Zipper: That’s exactly right. A car that is taller and heavier is going to exert more force in a crash. That is bad news for someone who’s in a smaller car on the other side of that incident. And by the way, we are now at a 40-year high in the U.S. in pedestrian and cyclist deaths.

Ryssdal: Another one of the invisible costs that you tick through is basically there is the environmental aspect of these things. The gasoline-powered ones spew out more pollution because they’re pushing heavier cars. Also, they are rougher on our highways.

Zipper: That’s exactly right. Cars that are big and cars that are heavy are going to require a lot of power to move. So that means a lot more power consumption, a lot more pollution and a lot more force exerted on the tires, which will erode faster, all else being equal. And we’re only now starting to realize how much of a problem that is with tire pollution leading to die-offs of fish and potentially harming other wildlife as well.

Ryssdal: All right, so here comes a potentially touchy question. If you look at car ads, and this has been true for many years, it’s all about the freedom of the American road and the freedom to drive bigger cars. I’m an American, and I want to drive a big SUV or a truck, by golly, right? This is an American phenomenon for a whole lot of reasons.

Zipper: That’s right. But in America, we also believe in markets. And we believe that people should be able to buy what they want at the appropriate price. And the problem in this country is that for decades, people who buy enormous, very heavy cars have been creating societal costs that they aren’t paying for. That’s what’s called a market failure. So if you want the market for automobiles to succeed, we need to make sure that when people are shopping for their next car, they are considering the societal costs of their purchase, which is going to be a lot greater if they’re going to be buying a very large model.

Ryssdal: It’s not a free market in this country, right? There are government regulations. And you do point out in the piece, I think Washington, D.C., if you drive a heavier car, you have to pay a heavier registration fee, right? Because those cars are heavier. And so there is some government influence happening here.

Zipper: There’s starting to be. One example that I cited in the Slate article, which I think is quite smart, is in the District of Columbia, where the most heavy SUVs and trucks will now require a vehicle registration fee that can be seven times higher than those same fees for people who are registering a very small sedan. So you know, with policies like that, there is a recognition that if you’re going to buy a vehicle model that’s more dangerous and destructive, you’re going to have to pay more. I think that’s entirely appropriate.