Electric vehicles, like the Hummer EV, should be taxed in the U.S. if they weigh too much.

On Sunday, President Joe Biden directed his megawatt grin toward a worthwhile cause: getting Americans to ditch their gas-powered cars. “On my watch, the great American road trip is going to be fully electrified,” he tweeted, pushing the up-to-$7,500 federal tax credit Americans can now receive by buying a new electric vehicle. A picture showed him smiling from inside of one of GMC’s new all-electric Hummers.

There were a few problems here. For one thing, with an MSRP of around $110,000, that EV is too expensive to qualify for the tax credit. For another, at 4.5 tons, it is hardly an environmental standard-bearer; one recent study found that it is actually worse for climate change than gas-powered sedans. And finally: Imagine getting hit by that thing.

The president, like the country he leads, has something backward about overhauling America’s automotive fleet in the face of a changing climate. It isn’t just about how our cars work. It’s about how big they are.

How do we fix that? By being a little more like Norway.

Norway is the global leader of electric vehicles, with fully 87 percent of new cars purchased last year at least partially powered by electricity. The country’s embrace of EVs is no accident: Buyers benefit from enticing government incentives, such as an exemption from a standard 25 percent car tax, that have delighted EV carmakers. (“I’d like to thank the people of Norway again for their incredible support for electric vehicles,” Tesla CEO Elon Musk tweeted last month. “Norway rocks!!”)

But now the Nordic nation is changing course. This month Norway implemented new taxes on car purchases that scale with vehicle weight. Although the fees are much higher for gas guzzlers, EV buyers must now pay them too—at a rate of NOK 12.50 ($1.26) per kilogram. (The first 500 kilograms are untaxed.) For larger EVs, the added expense can be significant: An Audi e-tron, one of Norway’s most popular models, now costs around $2,600 more than it did before.

Slapping new taxes on EVs might seem like a head-scratcher, especially since around 4 in 5 cars on Norwegian roads are still gas-powered. But the country’s new weight-based car fees are a sensible move to address two critical drawbacks of oversize EVs: These models exacerbate climate change, and they endanger everyone else on the street. Other countries—and U.S. states—should follow Norway’s lead.

To be clear, all gigantic cars create significant societal problems, regardless of their power source. Heavier vehicles require more energy for propulsion, which helps explain why gas-powered SUVs and trucks have pitiably low fuel efficiency compared with sedans. (The Ford Bronco, for instance, gets 22 mpg on the highway, compared with 39 mpg for the Toyota Camry.) Larger SUVs and trucks also generate additional force during a crash, endangering anyone not inside them. Researchers have linked the ascent of SUVs to the rising number of American pedestrian deaths, which hit a 40-year high in 2021.

In the United States, federal officials invited the rise of gas-guzzling SUVs and pickups in 1975, when they created a fuel-efficiency loophole big enough to, well, drive a truck through. Today 4 in 5 new American cars are SUVs or trucks, up from less than 1 in 2 in 2000. With gas prices higher in Europe, continental car buyers have been slower than their U.S. peers to embrace vehicular enormity, but SUV sales there have surged 900 percent in the past 20 years, claiming over 40 percent of the European car market. (Pickups, meanwhile, remain a peculiarly American obsession.)

The electrification of cars addresses some, but not all, of the problems posed by the largest models—but it also creates new ones. Electric cars do not use gasoline, so the traditionally terrible mpg of SUVs and trucks is no longer an issue. But EVs still require energy to move, and generating it creates emissions. Bigger electric vehicles demand more electricity, which produces significant greenhouse gases—potentially more per mile than gasoline-powered sedans.

Another environmental risk makes giant EVs even more of a problem. The size of an EV battery scales with vehicle weight, since heftier cars require more power to move. As a result, the biggest EVs have truly enormous batteries—like the 3,000-pound battery that powers the 9,083-pound Hummer EV. Gigantic batteries consume larger amounts of critical minerals like graphite and lithium that are in short supply worldwide.

“If we can redistribute these resources—instead of putting them in a Hummer, put them in smaller cars or e-bikes—that’s preferable,” said Jay Turner, a professor of environmental studies at Wellesley College and the author of the book Charged: A History of Batteries and Lessons for a Clean Energy Future. Supporting his point, a recent study found that SUVs are so inefficient that electrifying them instead of smaller vehicles could actually worsen climate change.

Largely because of their batteries, electric vehicles are typically around 30 percent heavier than equivalent gas-powered models. That leads to yet another concern of bigger EVs: the added force they exert during a crash. Already, the Insurance Institute of Highway Safety is revising its crash safety tests to account for the unprecedented weight of certain EVs. As National Transportation Safety Board chair Jennifer Homendy warned in a recent address, the tonnage of goliath-like EVs portends danger for any road user not inside one—especially those walking and biking.

A recent study found that SUVs are so inefficient that electrifying them instead of smaller vehicles could actually worsen climate change.

To sum up: The purchase of each oversize EV makes climate change harder to mitigate, while placing other road users at greater risk. Economists call these societal costs “externalities,” a kind of market failure that, unaddressed, leads to skewed purchase decisions because buyers see only their own costs, ignoring those borne by everyone else.

The economists’ solution? A tax or fee that forces consumers to consider their choices’ impacts on others. This is the beauty of weight-based car fees like Norway’s: They nudge buyers away from the most massive and damaging car models and toward those that are smaller.

Norway’s new fees land especially hard on anyone buying an oversize car that runs on gas, potentially adding tens of thousands of dollars to the purchase price. That makes sense, given large SUVs’ inefficient use of fossil fuels. But gigantic EVs impose costs too—something that Norway now acknowledges.

France, by contrast, also charges weight-based car fees, but EV buyers don’t have to pay them. (In a 2019 policy brief, a research group within the French government recommended removing that exemption.) Pierpaolo Cazzola, the director of the European Transportation Research Center at the University of California–Davis, said that climate-focused European officials are giving new consideration to weight-based fees for EVs. “It’s a resource-allocation argument,” he said. “There is growing awareness that we’re talking about a limited battery supply chain.”

But in the United States, the federal government has shown no signs of taxing cars by weight, despite Department of Transportation Secretary Pete Buttigieg’s declaring the rising number of traffic deaths “a national crisis” (which enormous cars make harder to solve) and President Biden’s setting a goal that EVs comprise half of all new cars sold in 2030 (which will be harder to reach if massive EVs hog battery resources).

“Given the politics at the national level, it’s almost impossible to imagine the federal government implementing weight-based vehicle fees,” said Turner. “It’s much easier to see a state doing something like this.”

The District of Columbia offers a model. The city last year overhauled its car registration fee schedule, charging owners of cars weighing over 6,000 pounds $500 a year, almost seven times more than the cost of registering a modest-sized sedan. Acknowledging the added weight of electric batteries, the District offers EVs a 1,000-pound credit that preserves the incentive to go smaller.

Carmakers, which have grown reliant on pricey SUVs and trucks, were less than pleased by D.C.’s move. The Alliance for Automotive Innovation, an industry group, sent a letter to D.C. councilmembers warning that the city’s new policy “will capture a growing number of EVs that are expected to come to the market over the next few years and will act as a disincentive to their purchase.”

To which D.C. officials might respond, “Great!” Disincentivizing the purchase of the most societally damaging EVs is exactly what we should want. Moreover, carmakers themselves determine which EVs “come to the market”; making the biggest models more expensive might force a welcome reevaluation of their product development plans.

Even the stiffest weight-based fees still leave buyers with plenty of reasonably sized EV options, including many vehicles that weigh less than 5,000 pounds, like the Tesla Model 3 and Hyundai IONIQ 5. The Alliance for Automotive Innovation’s letter implied that enormous EVs are inevitable, but that view is not universally held among car executives. The CEO of Citroën, Vincent Cobée, recently said he expects that “people will start limiting weight and battery sizes, either through tax, through incentives, through regulation, through naming and shaming.”

And they would be right to do so. Whether powered by gasoline or electrons, colossal vehicles like the Hummer are a societal malignancy, hindering our ability to address climate change while placing other road users in greater danger. Rather than cheer them on, leaders like Biden should be taxing the hell out of them.

Lucas Peilert provided research assistance.