U.S. Vehicle Sales Fall 13.2% Amid High Gas Prices and Tight Credit.

Vehicle sales in the United States fell last month to their lowest level in 16 years, as consumers continued to shun large trucks because of high gas prices, and tight credit kept less creditworthy customers off lots.

A Ford plant in Oakville, Ontario.

The automaker reported that sales in the United States fell 15 percent in July from a year ago.

Sales were down 13.2 percent, at a time when the companies had expected to begin seeing an improvement.

Instead, the five largest automakers each reported sales declines on Friday. Sales fell 26.1 percent at General Motors, the largest car company, while Chrysler, which used to be the third-largest, reported a 28.8 percent decline and came within a few thousand sales of falling to sixth place. The Ford Motor Company posted a 14.7 percent decline.

Together, the three Detroit automakers accounted for just 42.7 percent of the vehicle market last month, selling about 150,000 fewer vehicles than they had a year earlier.

The declines in the United States market affected foreign automakers too.

Toyota Motor reported an 11.9 percent decline, while Honda, which builds fewer trucks than its rivals and was the only large automaker to report a sales increase for the first half of the year, said its July sales decreased 1.6 percent. Nissan’s sales rose 8.5 percent on strong demand for its small cars.

As recently as this spring, executives in Detroit forecast that auto sales would rebound in the second half of 2008, as consumers spent their federal rebate checks and overcame difficulties in the housing market. But the July sales figures suggest that will not be the case.

In fact, the industry’s annualized sales rate of 12.55 million was its lowest since April 1992, showing that the market is continuing to deteriorate.

Soaring borrowing costs for the automakers’ financing arms and other lenders have led to higher automotive loan rates and tighter credit standards, which have cut sharply into sales. G.M. said it is losing 10,000 sales a month that it used to get from customers with below-average credit ratings.

“In the next several months, or even the next year I would say, the unfolding credit situation that customers are facing in dealerships will take center stage,” said James D. Farley, Ford’s marketing chief. “A lot more creativity has to take place in the finance and insurance office to sell a car now.”

Meanwhile, leases are becoming significantly harder to obtain, with Chrysler no longer offering leases through its financing arm.

G.M. and Ford said on Friday that they will cut back on leasing but remain committed to that business.

Falling sales of sport utility vehicles and pickup trucks have caused resale values of those vehicles to plummet, and that has turned many leases into huge money losers for the automakers. Unprofitable leases led to write-downs of $2.1 billion for Ford and $716 million for G.M.’s financing arm, the General Motors Acceptance Corporation, which it partly owns. GMAC this week halted subsidies for leases in Canada.

“All the risk, all the liability and all the expense is being put onto the consumer with this move away from leasing,” said Rebecca Lindland, an analyst with the research firm Global Insight. “There may be unintended consequences to this move, and they may be unpleasantly surprised that consumers walk away and go someplace else.”