WASHINGTON -- A top Toyota technology expert today urged people to temper expectations for what plug-in hybrid vehicles can accomplish.

Bill Reinert said that the demands of real-world driving, such as rapid acceleration on freeway entrances, could dramatically reduce the all-electric range of plug-ins, whenever they hit the market.

"When we see the (claims of) 100 mile-per-gallon stuff, not everybody's going to get 100 miles per gallon," Reinert said.

He is national manager of the advanced technology group for Toyota Motor Sales U.S.A. Inc. He was on a panel at Washington conference on plug-ins and afterward spoke to Automotive News.

A plug-in hybrid would have a more robust battery pack than a traditional gasoline-electric hybrid. In theory, with recharging from electrical outlets, it could operate much longer on electric-only power than other hybrids.

Proponents contend that an all-electric range of 40 miles would satisfy the daily needs of most drivers, giving them the equivalent of 100 mpg or more and dramatically cutting petroleum demands.

But just as some consumers have been disappointed by the real-world mileage of regular hybrids, plug-ins may not live up to those high hopes, Reinert said.

Green car wars

General Motors is planning to have the plug-in hybrid Chevrolet Volt on the market in 2010. Toyota has said it expects to have a plug-in ready for fleet customers by 2010.

The high-profile conference, organized by the Brookings Institution think tank and Google.org, dealt with the question of what government's role should be in promoting plug-ins.

Mark Fields, Ford Motor Co. president for the Americas, said in an address that significant government funding is needed for development of domestic production of advanced batteries and for retooling of plants.

Government also needs to resolve how people pay for recharging, if it is not done at home, and to establish a recharging infrastructure, especially for people without garages.

Help from Washington?

Bruce Andrews, Ford vice president of government relations, told Automotive News that near-term prospects for tax measures to benefit plug-ins are not good.

But next year, if Congress enacts legislation to cap greenhouse gases, the sale of emissions permits could provide a source of revenue for programs benefiting advanced technology vehicles, he said.

Tom Kuhn, president of the Edison Electric Institute, representing utility companies, said at the conference that big changes in policies are possible because "people in this country are mad."

Felix Kramer, founder of the California Cars Initiative and an early proponent of plug-in hybrids, said, "It is time to electrify transportation as much as possible."