DALLAS — Although median family income continued on a downward slope in the first quarter, the total cost to buy and finance a new vehicle dropped at a much steeper pace, thanks largely to sharp declines in interest rates, according to Comerica Bank's Auto Affordability Index.

Specifically, it took 21.5 weeks of median family income to buy an average-priced new model in the first quarter, which was down 1.3 weeks from the previous quarter and marked a new record low.

Moreover, the average total cost to buy and finance a new vehicle was $26,000, compared with $27,700 in the fourth quarter of 2008.

"Part of the sharp decline in interest rates on car loans may have reflected some normalization of conditions in credit markets," explained Dana Johnson, chief economist at Comerica Bank.

"However, with consumers sharply cutting back on their spending in the context of the severe recession, the car companies became much more aggressive in offering reduced financing rates as well as other types of discounts," she continued.