DETROIT — U.S. buyers shrugged off economic worries and snapped up SUVs and pickups last month, surprising the auto industry and raising hopes that a bumpy year will end on a high note.

Big trucks typically sell when the housing market and construction industry are strong, gas prices are low and consumer confidence is high. None of those was true in September. The economy remains weak, confidence is shaky and a gallon of gas prices cost nearly $1 per more than in September 2010.

But other factors boosted truck sales. Small businesses must eventually replace aging fleets of work trucks, and auto companies offered some good deals to clear out 2011 model trucks. They also stepped up their marketing. And consumers are learning to live with economic uncertainty.

U.S. vehicle sales rose 10 percent from last September, according to Autodata. September saw the fastest sales pace since April, and automakers expect that pace to stay steady for the rest of this year.

Nearly 54 percent of vehicles sold were trucks and SUVs, the highest percentage this year. That’s good news for automakers, which make much bigger profits on trucks and SUVs. Truck sales at General Motors, Chrysler and Ford grew in the double digits, outpacing cars. Even Honda, which normally gets the bulk of its sales from cars, sold 3,000 more trucks than cars.

A shortage of cars is another reason truck and SUV sales were strong. Analysts had expected more Japanese cars to fill showrooms after months of shortages related to March’s earthquake. New Honda vehicles arrived at dealerships last week, and Toyota’s new Camry sedan recently went on sale, but they were too late to give September totals a boost.