A U.S. market research firm says light-vehicle sales in China are eclipsing sales in the United States and that China could become the world’s biggest car buyer this year.

J.D. Power and Associates, which tracks the auto industry, said that in 2011, automakers expect to sell more than 18 million vehicles in China, which is about 40 percent more than in the United States.

The company says light-vehicle sales will continue to grow in China despite higher oil prices if its economy remains strong. It predicts that the U.S. car sales will be back to some 17 million units by 2018, but adds that by then, sales in China could come close to 33 million vehicles.

The firm says that in China, the sales will be spurred by increasing urbanization, rising incomes, growing numbers of dealers and massive road construction.

Earlier this week, J.D. Power & Associates predicted that India would become the third-largest market for auto sales by 2020, after China and the United States. India is currently the world’s sixth-largest vehicle market.