The oil and trucking industry sued to block California's new carbon fuel regulations Tuesday, saying the rules will raise costs but do little to reduce greenhouse gas emissions.

In a lawsuit filed in U.S. District Court in Fresno, lobbyists for oil refiners, truckers and other groups charged that the state's "low carbon fuel standard" is unconstitutional.

While not as well known as AB 32, the state's landmark climate-change legislation, the fuel standard is an important element of California's attempt to fight global warming.

It's a thicket of regulations that says transportation fuels must reduce their "carbon intensity," starting next year. It not only targets the carbon content of a fuel but also examines the amount of carbon emitted to produce the fuel and haul it to its destination.

The California Air Resources Board, which adopted the standard last spring, says it will save billions of dollars by reducing oil consumption and encouraging new biofuels and electric-vehicle technologies. While the new fuels "in the beginning are going to be expensive," eventually costs will come down, said board member Dan Sperling, a professor at the University of California, Davis.