After a strong start, U.S. new vehicle sales "leveled off" in the last week of September, according to J.D. Power & Associates, with the seasonally adjusted annualized rate, or SAAR, expected to come in below the researcher's expectation from a week ago.

Analysts have expressed concern about the stagnation of the auto industry, which despite some new car introductions, has struggled to significantly lift the current sales rate, reported The Wall Street Journal.

For total sales, the SAAR is expected to come in at about 11.5 million units in September, with fleet sales accounting for 20% of the month's sales. That estimate is under J.D. Power's prior estimate of 11.8 million units, but is still above August's 11.4 million and the 9.2 million rate a year ago. Sales are expected to jump as the industry struggled a year ago after the government's "Cash for Clunkers" program concluded.

"Consumers continue to grapple with high unemployment levels, a weak housing market and higher vehicle prices," said Jeff Schuster, a forecasting director at J.D. Power. "However, even with the weaker-than-expected close to September, retail volume has improved from recent levels and the recovery continues to progress slowly."

J.D. Power expects the retail annual selling rate to be about 9.4 million units for September, below its earlier 9.7 million estimate. The researcher said retail transactions are a more accurate measurement of true underlying consumer demand for new vehicles.

The higher projections were based on strength early in the month, which J.D. Power attributed to buyers delaying some of their purchases in late August, most likely waiting for Labor Day sales and hoping for increases in vehicle availability. J.D. Power said at the time that the industry was focused on economic indicators to gauge the level of recovery--echoing comments made by auto executives in recent months.

Last week, car-shopping website Edmunds.com said it expected the six top U.S. auto makers to report higher sales from a year ago, saying total sales should rise 28 percent.