World oil prices hit a new record high in Friday's trading in New York.
Crude oil for future delivery was as high as $55 a barrel before easing slightly at the close of trading.
The all-time-high price came just hours after the head of the U.S. central bank said high energy prices are likely to have less impact on the economy than the oil shocks of the 1970's.
In a Washington speech Friday, Federal Reserve Chairman Alan Greenspan said the economy is now more energy-efficient than it was back then.
Mr. Greenspan said the global economy will adjust even further by boosting energy exploration, increasing fuel economy and seeking alternatives to oil. He conceded that the adjustment is unpredictable and will take time.