Analysts expect sales to total about 14.3 million this year, up from 12.8 million last year. Sales peaked at 17 million in 2005 before hitting a 30-year low of 10.4 million during the recession in 2009.
Auto purchases have been robust in part because people are replacing cars they kept during the recession. The average age of vehicles on U.S. roads is nearly 11 years.
Bargain loan rates are also fueling sales. Some banks and credit unions are offering 2 percent financing to auto buyers with good credit. Rates from some automakers' finance companies are even lower.
The auto industry's recovery could inject itself into Wednesday's presidential debate. Obama has boasted that the bailout of General Motors and Chrysler helped save more than 1 million jobs. GM and Chrysler have since returned to profitability and hired thousands. Detroit's automakers build most of their cars in the Midwest, including Ohio, an election battleground state.
Romney has countered that the auto companies should have gone through bankruptcy with private funding and been allowed to recover with government-backed private loans.
The steady rise in home prices may also be affecting voter perceptions of the economy. The price increases coincide with higher sales fueled by record-low mortgage rates. The gains could embolden people who had been spooked by their shrunken home values or wary of selling or investing in a home.
A gauge of prices calculated by CoreLogic, a private data provider, jumped 4.6 percent in August compared with August 2011. It was the sharpest year-over-year gain in more than six years.
Other home-price measures have also risen. The Standard & Poor's/Case Shiller index rose in July compared with a year ago, a second straight increase.