General Motors Corp., the world's largest automaker, said it expects U.S. gasoline prices to be lower in three months than they are now, leaving intact a long-term consumer shift from cars to higher-profit trucks.

Gasoline now averages about $1.70 a gallon nationwide, about 60 cents a gallon higher than in June 1999, GM said. Still, adjusted for inflation, gas prices are about 20 cents a gallon lower than in 1979, when they helped Japanese companies increase imports of small, fuel-efficient cars, the automaker said.

GM expects its truck sales through dealerships to rise above half for the first time this year, to 53 percent, and to increase to about 60 percent next year. So far, U.S. gas prices haven't surged high or long enough to disrupt the long-term shift into minivans, pickups and sport utilities, which increasingly appeal to affluent buyers, said Paul Ballew, GM's top market analyst.

"Higher gasoline prices are having a short-term effect on this market, but it's not a sea change," Ballew told reporters.

U.S. gasoline prices will be lower this fall than now, Ballew said, though he declined to make a specific projection. U.S. consumers' average annual spending for gasoline has risen to $1,350 from $825 a year ago, he said.

The affluence of vehicle buyers is helping ease the impact of higher gas prices on car and light-truck sales. In 1998, the richest 20 percent of U.S. households accounted for more than half of new-vehicle spending, up from about 43 percent in the mid-1980s, Ballew said.

Investors monitor trucks sales closely because the Detroit-based automaker can earn $7,000 on each truck it builds, more than twice as much as on each car, analysts have estimated.

GM's sales of light trucks this year through May rose almost 12 percent from a year earlier to 1.06 million and were just under half of its total for light vehicles. Last week, the automaker said it would cut estimated third-quarter production of sport-utility vehicles, minivans and pickup trucks by 11 percent from a year earlier.