With gas prices at $3 a gallon, Bush said the best way for the nation to end its addiction to foreign oil is to make a transition more quickly to vehicles that run on renewable and domestically produced energy.

There is broad bipartisan agreement that the government needs to do more to fund research into vehicles powered by fuels including hydrogen and ethanol. But automakers have been slow to produce large numbers of alternative-fuel cars and trucks, and most experts predict the nation is many years, even decades, away from broadly offering consumers a cost-effective alternative to the vehicles they drive today.

In the short term, Republican leaders in Congress plan to join Democrats in calling on Bush to more aggressively investigate whether the major oil companies are unfairly driving up prices. But there are few policy options available to Bush and Congress to drive down gas prices as the summer travel season approaches. Price-gouging investigations, which lawmakers call for each time pump prices spike, rarely yield results. It also doubtful lawmakers will consider reducing or suspending the gas tax, because that money directly funds road repairs and highway improvements.

After touring the California Fuel Cell Partnership, a consortium of companies and government agencies that promotes hydrogen-powered fuel cell vehicles, Bush said the Energy Department is predicting higher gas prices in coming months and that more needs to be done to lower them.

"We are going to have a tough summer," Bush said. His top long-term solution: promote hydrogen, which he called the "fuel of the future."