Washington ? The Senate gave automakers a reprieve Wednesday by rejecting a plan to require that they produce cars, trucks and sport utility vehicles that run 50 percent farther on a gallon of gas.

The industry and its unions lobbied hard against requiring a 36 mile-per-gallon average by 2015. Supporters of the higher standard said it would save millions of barrels of oil and could be reached through current and emerging technologies.

Instead, the Senate by a 62-38 vote told the Transportation Department to develop new fuel economy rules over the next two years, but did not require specific mileage increases.

Separately, senators voted 56-44 to exempt pickup trucks from future mileage increases.

Sen. John Kerry, sponsor of the 36 mpg proposal, said that proposal which replaced his in a broad energy bill was “an artful dodge, a great escape” from doing anything about fuel economy. “We are going backward,” said Kerry, D-Mass.

Federal fuel economy rules have not changed in 15 years, noted Senate Majority Leader Tom Daschle, D-S.D., who said the vote was “a missed opportunity … to pass meaningful” standards.

The House already has turned down significant increases in auto fuel economy.

Automakers now are required to meet a fleet average of 27.5 mpg for sedans and 20.7 mpg for SUVs, minivans and pickups. Kerry’s proposal would have combined the two categories.

The average for all vehicles was 24 mpg in 2000, about what it was 22 years ago.

Conservationists say motor vehicles account for 40 percent the oil used across the country and that higher mileage levels would help reduce U.S. reliance on oil imports as well as address environmental problems such as climate change.

The Senate debate, however, focused on the potential fallout from the proposed mileage increase: job losses in the auto industry and the production of smaller cars, which could lead to more traffic fatalities while depriving Americans of lower-mileage but roomier minivans and SUVs.

Minority Leader Trent Lott displayed a picture of a two-seater, bubble-like subcompact a Daimler-Chrysler that gets 70 mpg and is sold only in Europe. “I don’t want every American to have to drive this car,” said Lott, R-Miss.

Kerry accused opponents of his proposal of “extraordinary, ridiculous scare tactics” prompted by the auto industry.

“No American will be forced to drive a different vehicle. The technology is available today to meet the higher standard,” Kerry said.

He cited a National Academy of Sciences study last year that concluded significant fuel efficiency improvements were possible without making cars smaller and lighter.