DETROIT (AP) - U.S. auto sales surged over Memorial Day weekend, boosting an otherwise lackluster month for the auto industry.

DETROIT (AP) U.S. auto sales surged over Memorial Day weekend, boosting an otherwise lackluster month for the auto industry.

Sales of new cars and trucks were expected to be flat or drop slightly in May. Car buying site TrueCar.com forecast total sales of 1.59 million vehicles, down 1 percent from the same month a year ago.

But TrueCar said that was partly because automakers sold fewer vehicles to rental car companies and other fleets. Sales to individual buyers were expected to rise 2 percent, and over Memorial Day weekend they jumped 7 percent.

General Motors said its sales rose 3 percent over last May, while Fiat Chrysler's were up 4 percent. Both automakers benefited as buyers continued to shift from cars into small and medium-sized SUVs. Sales of the Jeep Cherokee SUV were up 23 percent, while sales of the GMC Acadia jumped 67 percent.

May is typically one of the biggest sales months of the year, as buyers flush with tax returns look forward to summer road trips. Last May, after a particularly harsh winter, sales reached a nine-year high.

It will get increasingly difficult for the industry to match those kinds of numbers. U.S. sales are expected to reach 17 million this year, near their historic peaks of a decade ago.

But the industry isn't alarmed. Consumer demand remains so strong that Ford is shortening its annual two-week summer break to one week at its six North American assembly plants. Chrysler has canceled its usual shutdown at four assembly plants in the U.S. and Mexico.

GM's sales rose 3 percent to 293,097 vehicles. Sales of its best-seller, the Chevrolet Silverado pickup, rose 11 percent, and Buick's two small SUVs the Encore and Enclave both saw 20-percent gains. But car sales were weaker. Sales of the Chevrolet Cruze dropped 27 percent.

FCA's sales totaled 202,227 vehicles. It was the company's best May since 2005. Jeep sales rose 13 percent. Sales of FCA's best-seller, the Ram pickup, rose 8 percent, while sales of Ram's ProMaster van more than doubled.