U.S. auto sales in March are expected to rise 8 percent and the annual sales pace should top 15 million for the fifth straight month as consumers shake off worries about the economy, according to research firms J.D. Power and Associates and LMC Automotive.

Sales of new cars and trucks in March are expected to rise to 1,465,100 vehicles, while the annual sales pace is forecast to hit 15.3 million vehicles, J.D. Power and LMC said in a joint report. Since November, the annual rate has ranged from 15.3 million to 15.5 million.

Auto sales are an early indicator each month of economic health. The industry has so far proven stronger than the overall U.S. economy as the record high age of cars and trucks on the road has reached more than 11 years, and easier availability of credit pushed consumers into the market.

"We expect the economic environment to improve throughout 2013, as the likelihood of a dark cloud slowing the recovery pace diminishes," LMC senior vice president Jeff Schuster said in a statement. "Consumers do not appear phased by headwinds from Washington, as growth in auto sales are outperforming earlier expectations."

The U.S. auto sector is scheduled to report March sales results on April 2. In February, sales rose nearly 4 percent, delivering a better-than-expected performance on strength in the U.S. housing market.

Many executives and analysts have forecast 2013 U.S. industry sales to finish in the 15 million to 15.5 million range.

J.D. Power and LMC said the average retail transaction price in March rose 3 percent from last year to $28,504 per vehicle.