SANTA MONICA, Calif. —TrueCar.com said it anticipates both new- and used-vehicle sales to be down from last month, while the industry average incentive spending per unit is expected to be up.

New light vehicle sales, including fleet, are expected to be 1,041,435 units in July, down 0.8 percent from June 2010 and down 0.9 percent on a month-over-month basis. The vehicle pricing and trends Website also anticipates fleet and rental sales will make up 17 percent of total industry sales for July 2011,

The seasonally adjusted annualized rate (SAAR) is expected to reach 11.4 million new-car sales, down from 11.5 million last month and down from 11.6 million during the year-ago period.

Used-car sales are estimated to reach 4,052,086, up 2.3 percent from July 2010 and down 1.8 percent from June 2011. The site also reported that four used vehicles are being sold for every new vehicle sold.

Additionally, the average incentive spend per unit is expected to reach approximately $2,418 in July, an increase of 0.7 percent from June 2011 and a 15.1 percent decrease from July 2010. The increase comes despite retail sales decreasing 2.4 percent compared to July 2010 and 0.4 percent from last month.

 “Incentives remained relatively flat compared to last month, but as inventories continue to build, automakers will need to increase incentive spending for the rest of the year to help spur some demand.”

TrueCar.com’s forecast is based on actual transaction data that is refined by other factors including sales, inventory, incentives, fuel prices, and macro economic data, according to the company. The forecast is not adjusted for selling days in year-over-year percentage changes.

*Used car sales figures include sales from franchise dealerships, independent dealerships and private party sales