WASHINGTON - Some automakers are close to calling for fuel economy standards as high as 36 mpg for cars and 30 mpg for light trucks, sources said today.

The proposal would be offered as an alternative to a fuel economy measure scheduled to be considered by the full Senate the week of June 11.

The Senate bill calls for a fleetwide average of 35 mpg by 2020 -- about 40 percent higher than today -- and further increases of 4 percent a year until 2030. Lobbyists for the industry have labeled the bill extreme and untenable.

But with congressional sentiment high for action to reduce petroleum consumption and cut greenhouse gas emissions, automakers probably cannot simply kill the legislation.

One document circulating among lobbyists is a draft of alternative legislation prepared by Sen. Carl Levin, D-Mich., an industry ally. It calls for a car standard of 36 mpg by 2022 and a truck standard of 30 mpg by 2025, up from today's 27.5 for cars and 22.2 for trucks.

The alternative would enable automakers to avoid fuel economy standards altogether if they could show they were building vehicles with better fuel economy and lower emissions.

Levin's office did not say whether he will offer the draft as an alternative or it is merely a work in progress.

Charles Territo, a spokesman for the Alliance of Automobile Manufacturers, said the group's member companies "are hopeful that there will be an alternative that we can support." The alliance represents the Detroit 3, Toyota and five other automakers.

Discussions about options are part of intense behind-the-scenes activity leading up to Senate debate on the fuel economy bill.

Environmental lobbyists are working to toughen the bill on the Senate floor. They argue that so-called off-ramps in the bill are giant loopholes.

The off-ramps would allow federal regulators to set standards lower than what the bill calls for if the regulators find the standards are technologically or economically too tough for the industry to meet.

You may e-mail Harry Stoffer at hstoffer@crain.com