Obama, an Illinois senator and the front-runner for his party's presidential nomination, has made fighting climate change a key issue of his campaign, and as fuel prices soar, he has repeatedly called on car makers to increase fuel efficiency standards.
Without specifically telling Americans to stop buying gas-guzzling sport utility vehicles, the Illinois senator said higher fuel prices would lead to a shift.
"We've seen that this quarter. People are changing their behavior and we've seen a slump in the sales of SUVs and big trucks and a drastic spike in cars both medium size and small," he told reporters on his campaign plane.
Obama put responsibility on car makers to make vehicles more fuel efficient.
"They've done a better job of investment than they have in the past. There's still more work to do, and the federal government should help them do it," he said.
Obama, who spends most of his time traveling around the country on a plane and in cars driven by his Secret Service agents, does have a car of his own that is environmentally friendly.
"These days I don't drive much," he said. "I bought a hybrid, but we keep it in the garage mostly."