Plug-in electrified vehicles (PEVs) need product diversity and broad distribution to dealer lots to see sales gains outside of California, according to a new study.

While diversity in PEVs offered by automakers has improved, their low volumes at dealerships outside of California is hurting sales growth, according to the Union of Concerned Scientists (UCS). In its new study, “Electrifying the Vehicle Market: Evaluating Automaker Leaders and Laggards in the United States,” UCS studied automaker programs to bring PEVs to markets across the Northeast and West Coast. The study tapped into sales figures, model offerings, and availability on dealership lots.

California is well known for being the hub of PEV sales, and the figures validate that perception. More than half of U.S. PEV sales were in California last year, with 22 models available. In other states, most PEV models have been difficult to find, or aren’t available to consumers at all.

“You can’t buy a car you can’t find,” said David Reichmuth, a vehicles engineer at UCS and the lead author of the study. “One of the biggest barriers to EV adoption is that too many automakers fail to make electric options available. The future is electric, but when automakers don’t put effort into building and selling these cars – especially outside of California – they’re missing out on an evolving market.”

California’s Zero Emission Vehicle (ZEV) program, with the governor’s goals of seeing 1.5 million electric cars on roads by 2025, has helped push the state forward in sales. A robust vehicle rebate program has also been a tipping point for residents to purchase their first PEVs, but that’s been put on hold for now. California legislators and officials are working out the state budget and legislative items. Until approved with decisions on cap-and-trade expenditures, the state’s rebate program isn’t expected to be revived.

The UCS study sees BMW, GM, Nissan, and Tesla doing a better job at making electric car options available. In 2015, BMW was second only to electric-only automaker Tesla with percentage of sales coming from PEVs. Plug-ins made up 3 percent of BMW’s nationwide vehicle sales and 7 percent of sales in California.

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The study identifies Toyota, Fiat Chrysler, Hyundai/Kia, and Honda, as being slower to bring PEVs to market, or having limited vehicle production or availability. Toyota had some early success with a plug-in hybrid Prius, but currently has no other PEV on the market. Fiat Chrysler has had success in selling its Fiat 500e plug-in model in Oregon and California, but does not offer the vehicle for sale in other markets. Honda has had a selection of PEV offerings, but these cars have been offered in very limited numbers over the past several years.

The Northeast is a region with market potential that’s being missed out, the study said.

There have been fewer models to choose from and fewer vehicles available on the lot than in California. For example, in the first six months of 2016, reported about 2,800 PEVs were sold in the Oakland/San Francisco area, but only 317 in the Boston area.

Public education is crucial to moving sales forward, and that includes California, UCS said.

“Automakers and state officials should do a better job of letting drivers know about existing EV incentives,” said Reichmuth. “Our survey found that more than three quarters of California drivers didn’t know the state offers any plug-in electric vehicle incentives, and almost 80 percent weren’t aware of the federal EV tax credit. Together, these programs can lower the purchase price of a plug-in vehicle by over $10,000.”

Union of Concerned Scientists