For the past few years, electric vehicles have flooded onto America’s roads: Tesla Model 3s, Hyundai Ioniq 5s, even the occasional electric Hummer. In 2023, automakers sold almost 1.2 million all-electric cars to U.S. consumers, accounting for over 7 percent of total new car sales and a new national record.

But all those cars also need a place to plug in. And while the country is also expanding public charging, data show that EV sales are far outpacing growth in the U.S. charging network — endangering the transition to electric cars just as it’s starting to take off.

Between 2016 and 2023, EV registrations in the United States grew almost three times faster than the United States’ public charging infrastructure. In 2016, there were seven electric cars for each public charging point; today, there’s more than 20 electric cars per charger.

“You often hear about the chicken and the egg question between chargers and electric vehicles,” said Corey Cantor, senior associate for electric vehicles at BloombergNEF, an energy research organization. “But overall the U.S. needs more public charging.”

It’s a pivotal moment for U.S. charging infrastructure generally. Last month, Elon Musk fired the entire 500-member Supercharger team at Tesla, which had helped make the company’s network the most reliable and widespread fast charging in the country. The U.S. government has pledged $7.5 billion to build out more fast chargers, but as of the end of March, only seven stations and 38 individual chargers were up and running.

Many EV drivers don’t require public charging regularly — according to the Energy Department, around 80 percent of EVs are currently powered at home. But as Americans purchase more and more EVs, public chargers will be essential to support long road trips, help apartment-dwellers go electric and alleviate overnight pressure on electricity grids. Around one-third of Americans don’t have access to a garage or carport.

Experts say that there is no “magic number” for the best ratio of EVs on the road to public chargers. “It absolutely depends on the local landscape,” said Peter Slowik, U.S. passenger vehicles lead for the International Council on Clean Transportation.

Globally, there is about 1 public charger for every 11 EVs, according to the International Energy Agency. But in countries where there are more single-family homes and garages, the ratio could be lower. In China — where many drivers live in apartment buildings and multifamily housing — there is approximately 1 charger per 8 electric cars. (China has over 1 million public chargers, compared to roughly 168,000 in the United States.) In Norway, on the other hand, there is 1 charger for every 34 electric cars.

Even if there is no ideal number, studies of the U.S. charging landscape have found that there should be a public charger for every 10 to 15 electric cars — far more than we have right now. The higher the number of EVs per charger, the more likely it is that drivers face lines or other inconveniences as they try to fill up.

And the fact that not all cars can use the same charger can make its low numbers even more difficult for drivers. EVs in the United States have different connectors that only work on certain chargers — Tesla drivers need an adapter to use non-Tesla ones, and vice versa.

“Just because we have the number of EVs per charger, doesn’t mean that everyone can access them,” said Cantor.

In a way, the United States’ slow charging build-out could be a benefit in the long-term: Many automakers have now promised to switch to Tesla’s charging connector in the next few years, which could help put most cars on the same system.

Not everyone agrees there is a delay. Slowik says that his team’s research shows that the United States is on-track for building out the charging needed over the next eight years. An increase in the number of EVs per public charger is a natural part of the adoption process, he argues, that will subside with more sales and as more chargers come online.

But others say that if EV sales continue to go up without an accompanying increase in chargers, consumers could face long lines and turn against the vehicles.

​​​​​​​“I always come back to the two barriers around EV adoption, which are upfront cost and charging anxiety,” Cantor said. “If you’re not making those concerns better, then you’re not helping.”