The United States senate has bowed to claims from vehicle makers that tough new fuel economy rules would kill off sport utility vehicles and rejected a proposal to boost corporate average fuel economy to 36mpg.

Senators rejected the bipartisan bill proposed by Democratic senator John Kerry of Massachusetts , supported by Republican John McCain of Arizona and numerous environmental groups, to ratchet the CAFÉ figures up by 2015.

Instead, by a majority of 68-32, the senate adopted a bill, proposed by senators from two vehicle-manufacturing states - Democrat Carl Levin of Michigan and Republican Christopher Bond of Missouri - which simply directs the Department of Transport#;s National Highway Traffic Safety Administration (NHTSA) to develop new fuel economy regulations over the next two years.

But the bill requires no specific improvements over the current CAFE standards of 27.5 miles per gallon for cars and 20.7mpg for light trucks, which includes SUVs.

Rubbing in the victory for vehicle makers, senators also succumbed to pressure from their farm state colleagues and voted 56-44 to exempt America#;s huge, and mostly V8-powered pickup trucks from future fuel economy improvements.

During intensive lobbying it had been argued that the Kerry-McCain proposal would kill off SUVs, reduce vehicle occupant safety by forcing people into smaller vehicles (as was the case in the 1970s and 1980s) and, it was claimed, even force farmers out of their huge pickups into golf carts.

It was also claimed Japanese nameplates would have an unfair advantage as they produce fewer large SUVs and pickups.

Quoted by The Car Connection website, Eron Shosteck, a spokesman for the Washington-based Alliance of Automobile Manufacturers, said the amendment approved by the senate would help both consumers and workers by protecting choices. "This is a victory for consumers, public safety and autoworkers," he said.

DaimlerChrysler senior vice president of external affairs and public policy Robert Liberatore said the company "appreciates the Senate's endorsement of Senator Levin's and Senator Bond's reasonable and achievable process for increasing fuel economy standards in this country.

"We expect and are planning for increases in our corporate average fuel economy in the coming years and commit to work with NHTSA to do so in a way that does not compromise safety. We are investing billions of dollars in advanced technologies such as fuel cells to gain competitive advantage in the worldwide marketplace."

The American International Automobile Dealers Association (AIADA) said passage of the Bond-Levin amendment was "a victory for American consumers and their freedom of vehicle choice in the marketplace."

"Efforts to dramatically increase CAFE standards threatened to compromise vehicle safety and would have eliminated some of the most popular vehicles on the road today," said AIADA president Walter Huizenga.

"This was a hard-fought victory over an unreasonable proposal that threatened our member's jobs and their business investments. Bond-Levin is a sensible provision designed to seek rational increases in CAFE via the regulatory process without jeopardising consumer choice and safety," Huizenga added.

Associations representing the automotive supplier industry also hailed the senate's passage of bipartisan legislation. "Today's decision by the senate is right for the US automotive supplier industry and for consumers," said Jeff Trask, vice president of government relations for the Motor & Equipment Manufacturers Association (MEMA).

"The amendment directs NHTSA to establish new fuel economy requirements after considering a number of important factors. This will help ensure that CAFE standards are set at the appropriate level, thereby allowing our industry's contributions to automotive innovation in many areas to continue.

"Consumers will also benefit, as their needs are among those NHTSA must consider in setting new standards."

Environmental groups such as the Sierra Club have criticised the axing of the first attempt to boost CAFÉ figures since they were first mandated in the 1970s.

Some groups argue that consumers and even vehicle industry workers want to see improved fuel economy figures and that the decision will, in time, simply hand more market share to the Japanese whose vehicles are mostly more fuel-efficient.