For the week of October 20, Black Book reports that overall car values decreased by 0.63 percent and volume-weighted truck values decreased by 0.62 percent.

Overall, declines in car values are similar to the average weekly depreciation seen in the previous four weeks, according to Black Book.

"Car segments that performed relatively well last week include Upper Mid-Size Car and Premium Sporty Car, declining by only 0.26 percent and 0.28 percent, respectively," said Anil Goyal, VP of Automotive Valuation and Analytics for Black Bo0k.

Overall, the volume-weighted truck values decreased by 0.62% last week. This is much higher than the average depreciation rate of 0.35 percent seen in the previous four weeks.

"Truck segments that performed relatively well last week include Compact SUV and Mid-Size Pickup, declining by only 0.07 percent and 0.19 percent, respectively," Goyal observed.

Black Book also continues to take a look at the depreciation trends of specific Volkswagen diesel vehicles affected by the recent emissions/software situation. The report shows that since September 18, each vehicle has displayed a higher level of depreciation compared with its competitive gas models:

• Golf Diesel: -8.7%; Gas Models: -3.7%

• Jetta Diesel: -13.8%; Gas Models: -3.7%

• Beetle Diesel: -9.3%; Gas Models: -3.2%

• Passat Diesel: -13.5%; Gas Models: -2.8