Democratic presidential hopeful John Edwards says a wave of mergers in the oil industry should be investigated by the Justice Department to see what impact they have had on soaring gasoline prices.

During a campaign stop in Silicon Valley on Thursday, Edwards will berate the oil industry for "anticompetitive actions" and outline an energy plan he says would reduce oil imports "and get us on a path to be virtually petroleum-free within a generation."

"Vertically integrated companies like Exxon Mobil own every step of the production process — from extraction to refining to sale at the pump, enabling them to foreclose competition," says an outline of Edward's energy plan provided to The Associated Press by his campaign.

Edwards' call for a major shift away from oil use would include, according to the document:

— An increase of federal auto fuel economy requirements to 45 miles per gallon from the current 27.5 mpg by 2016.

— Expansion of the use of biofuels such as ethanol, including a requirement for oil companies to make available E-85 fuel (which has 85 percent ethanol) at a quarter of their stations. Edwards wants all new cars to be able to use E-85 by 2010.

— Mandatory restrictions on emissions of carbon dioxide with an aim to cut CO2 and other greenhouse gases by 80 percent by mid-century.

— Creation of a $13 billion energy fund from the sale of greenhouse gas permits and ending some tax breaks for the oil industry. The money would be used to support biofuels and conservation technologies.

Many of Edwards' proposals — from cutting greenhouse gas emissions to investigating oil industry consolidation — have been the subject of numerous hearings in Congress this years, as has calls by Democrats to make automobiles more fuel efficient.

Rival Democratic presidential candidates, including Sens. Hillary Clinton and Barack Obama, also have called for expanded use of ethanol and other measures to reduce the country's reliance on oil.

But Edwards' message may resonate especially in California, the nation's most delegate-rich state, which has perennially high gasoline prices.

On Wednesday, the average regular-grade gasoline in California was $3.41 per gallon, according to the AAA Daily Fuel Gauge Report. The national average was $3.20 per gallon, compared to $2.85 a year ago.

But Tupper Hull, spokesman for the Sacramento-based Western States Petroleum Association, said the prices reflected market rates, and an antitrust investigation would be a waste of time. He said the industry has been the subject of more than 20 state and federal investigations over the past two decades.