Eight states have pledged to increase sales on electric and hydrogen-fueled vehicles by making their prices more appealing to consumers, CNN Money reported.

By developing standards for charging stations, expanding financial incentives to buy the cars and lowering consumer electric rates, the states aim to increase the number of vehicles on the road to 3.3 million by 2025.

The states involved, which represent nearly a quarter of U.S. auto sales, are California, New York, Connecticut, Maryland, Massachusetts, Oregon, Rhode Island and Vermont. An estimated cost for the initiative has not been released.

California has spearheaded the program, announcing its goal of 1.5 million new zero emission vehicles in the next 12 years.

Sales of these vehicles have underperformed both government and automaker expectations, Mike Omotoso, an analyst with LMC automotive, told CNN. Even when factoring in a $7,500 federal tax credit and state tax credits of up to $2,500, zero-emission vehicles can cost more than gasoline-powered vehicles, he said.

Automakers are under pressure from the federal government to increase the average mileage of the vehicles they sell, according to CNN. Zero-emission vehicles are also supposed to make up at least 15 percent of sales by 2025.

The Electric Drive Transportation Association said the market for electric and hybrid vehicles is growing steadily, especially as word of mouth spreads from satisfied customers.

"Ultimately what sells the vehicles is people getting in them and driving them," said Brian Wynne, the group's president.

Global Automakers, a group representing Toyota, Honda, Subaru and 10 other auto companies, said its members were "pleased" states would be working towards a single plan.

"Getting the marketplace ready to support [zero-emission vehicles] is a shared responsibility and automakers are already making huge investments in developing the technologies," the group said.

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