It's a Wednesday evening in Washington, D.C., and you need to power up your Tesla.

You open the app. It shows that just one of eight chargers are available on M Street. A few blocks away, six chargers are open at a sluggish 72-kilowatt station. None are open in District Heights, and there's a 10-minute wait.

That's what Tesla drivers saw on their phones at 7 p.m. Sept. 4. Luckily for the area's EV drivers those stations were outliers among the 40 options within a 25-mile radius. So it's no fluke that the district ranks second in the country for its EV infrastructure. It even outshines on one metric. More on that later.

A new EV index for 2024 – released first to USA TODAY ahead of World EV Day on Monday – ranks Delaware at the top. The state leapt to first from 15th place in 2023 EV Index largely because more charging stations came on line with greater charging capacity.

Which states rank the highest and lowest in the EV Index

No state gets a perfect score in the index developed by HERE Technologies, a location data and technology platform, and SBD Automotive, a global automotive research firm. But it's clear EVs and their infrastructure are gaining a foothold in the Northeast and Southwest.

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States with the most EV chargers per mile and most powerful chargers

The two metrics that likely matter most to current EV owners – especially on longer trips – is how many chargers are along a state's roads and how powerful they are. Delaware is among the top 10 for locations and power while Alaska trails in the bottom 15 for both categories.

Another part of the index looks at the balance of charging points to EVs registered in state. HERE Technologies and SBD Automotive say the number of charging points jumped 32% in the U.S. since the 2023 EV Index.

"Despite the progress in expanding EV infrastructure, slower growth in EV adoption highlights a persistent challenge: The need for a robust and reliable public charging network," Christopher Handley, HERE Technologies' vice president of dynamic spatial data, says in the release of the 2024 index data.

Ratio of chargers to EVs tips further out of balance

If there are too many vehicles to public charging points, people may be discouraged from buying EVs. Similarly, too few cars per charging points make it less likely organizations will build more stations.

SBD Automotive calculated the best charger-to-EV ratio for each state. The ratio is based on factors such as the number of roads, population density and the size and growth of their EV fleets. The target ratios for each state range from as high as 12.7 cars per public charge point in California to just 1.8 in North Dakota.

Which states lead the U.S. in EV ownership

The final piece of the EV index tracks how many EVs are on the road, which, again, plays into the calculations organizations make about EV infrastructure. California, Washington, D.C, and Hawaii have the highest percentage of registered EVs. North Dakota, Mississippi and Wyoming have the lowest.

The International Energy Agency estimates Americans will purchase 1.7 million fully electric and plug-in hybrids this year – about 300,000 more than last year. While the numbers continue to grow, the rate is slowing. IEA's estimates combined EV and PHEV purchases will be up 21% in 2024, down from 40% last year.

The IEA also estimates U.S. had a combined 4.8 million EVs and PHEVs on the road in 2023. That's a small fraction of 283 million vehicle registrations counted by the Federal Highway Administration in 2022.

How every state ranks based on 2024 EV index

At the city level, HERE Technologies and SBD Automotive found that Los Angeles, New York City and San Francisco continue to lead in AC and DC charging capacity while Texas cities Dallas/Fort Worth and Houston lag. Detroit had a 9-point drop in its ranking because the average charger power dropped while the ratio of EVs to chargers grew.