Auto industry executives, responding to studies warning that the Chinese market could become glutted, acknowledged the risk this week, but they said they were confident that they would not suffer a sudden downturn in Asia sales or get stuck with underused facilities.

Dieter Zetsche, chief executive of Daimler, said the Chinese authorities were being careful not to let the economy overheat. As more Chinese are able to buy cars, the market is "like Germany in the 1950s," Mr. Zetsche told a small group of reporters at the Geneva auto show. China is already the largest car market in the world.

Half of executives surveyed by KPMG believe that China will have too many automotive plants within five years. In addition, Bain & Co., the consulting firm, has warned that factories in China could be capable of turning out 40 million cars a year by 2015, 35 percent more than the market can absorb.

Car companies already have experience with a sudden downturn that left them with costly unused factory machinery and too many workers. They are only now returning to sales volumes as high as in 2007, when a global downturn began. Executives said they learned from that experience how important it is to keep a close eye on the market and to make sure they can cut production quickly.

Bayerische Motoren Werke, which reacted earlier than rivals to the downturn, has reduced payroll as well as fixed costs. The company has also increased parts sharing among different models, which saves money on purchasing, said Norbert Reithofer, the chief executive of BMW.

Even if companies do invest too much in China, the cost of overexuberance there is lower than it would be elsewhere, said Stefan Jacoby, chief executive of Volvo Cars. The Swedish carmaker, sold by Ford to Zhejiang Geely Holding Group of China, said last week that it planned to build a new factory in China and reach sales there of 200,000 vehicles by 2015.

Mr. Jacoby said he was still bullish on China. "If you talk to the Chinese they are much more positive than in Europe or the United States," he said. "There is tremendous momentum in this market."