During the past three months, the launch of 2008 model-year vehicles has pushed downward the resale values of two- and three-year-old passenger car and light trucks, according to vehicle appraisal guide Black Book.

From July 1 to Sept. 30, resale values fell by more than $300 for about 70 percent of these models, compared to just over 20 percent in the three-month period ending Aug 1, officials pointed out.

At the same time, Black Book reported that during the past three months, the level of depreciation has increased in relation to year-over-year figures. Domestic cars have declined 2 percent, while import cars dropped 3.9 percent. Domestic trucks decreased 4.6 percent, and import trucks dropped off 5.1 percent, the company said.

Year-over-year changes are less dramatic than the most recent quarter's performance would suggest, Black Book officials noted, due to the strength of the first six months of 2007. For the year, domestic cars fell 12 percent and import cars dropped 11.1 percent, they added. Import trucks decreased 12 percent, while domestic trucks led the market in retention, falling only 8.6 percent.