DALLAS — The purchase of an average-priced new vehicle took 24.1 weeks of median family income in the third quarter, according to the Auto Affordability Index compiled by Comerica Bank.

The latest reading is up one week from the second quarter, but down 1.1 weeks compared with a year ago.

Including finance charges, the total cost of buying an average-priced light vehicle was $28,929 in the third quarter, up about $1,200 from the second quarter. Family income barely increased in the latest quarter.

"The surprise to me was that the average amount of money spent on a new car increased about 5 percent to $25,200 last quarter, excluding financing costs," explained Dana Johnson, chief economist at Comerica Bank.

"In all likelihood, many moderate income buyers pulled out of the market due to the limited availability of financing, thereby temporarily inflating the average amount of money spent on a new car," he added.

"A sharp drop in loan to value ratios, to the lowest level in three years, was another indication that tight auto financing conditions were a restraint for many potential buyers," he concluded.