As temperatures begin to cool,  and we pass the middle of the month and look toward October, rising gas prices continue to have a “minimal” impact on used vehicle prices, according to NADA Used Car Guide’s Jonathan Banks.

The NADA UCG senior analyst explained that through the first half of the month, compact and midsize car prices declined more than their larger truck counterparts.

It seems this time around, as gas prices spike, consumers are not running to the lots to cash in their gas guzzler for a more fuel-efficient ride.

Specifically, compact car wholesale prices fell by 2.2 percent since August, while large pickups only depreciated by 0.7 percent — the lowest rate for all the segments NADA UCG tracks.

However, as  a collective, prices for utilities of all sizes (compact to large) and large pickups slipped more than last month, but the collective fall of 1.4 percent was “markedly lower” than historical norms for the season, Banks said.

"Market level depreciation through over the first half of the month checked in at just 1.5 percent, and overall prices continue to be abnormally resilient considering the steeper rates of loss normally witnessed over the period,” he noted.

“Historically the rate of value loss picks up through the fall, but so far that has not been the case. By comparison, depreciation in July and August reached 2.0 percent and 1.9 percent, respectively,” Banks further explained, noting the fall season is bucking trends already.

He went on to break down which segment's prices fell the most so far this month.

“The midsize van segment proved to be a bit of an outlier as it led other segments in terms of depreciation as so far this month prices for the segment have fallen by a substantial 3.2 percent,” Banks said.

Banks also targeted the primary “culprit” behind the steep price decline in this segment.

“Looking at recent sales data shows the primary culprit behind the steep decline to be an increased number of 2012 model-year fleet units of the Chrysler Town & Country and Dodge Grand Caravan in the auction lanes,” he noted.

In fact, auction volume for the Town & Country and Grand Caravan grew by 56 percent and 28 percent, respectively, on a monthly basis, NADA UCG reported.

“Historically speaking, early fall is usually the time of the year that many rental companies dispose of units that are no longer necessary because the summer rental rush has come and passed and rental companies trim their fleet portfolios as a result,” Banks explained.

And he doesn’t think the slide for midsize vans is over yet.

“Expect to see prices continue to soften over the next few weeks as volume works its way through the lanes, but prices should firm up again as we move deeper into the fall,” Banks contends.

Lastly, it was noted on the blog post that for luxury segments, both car and utility prices fell by 1.1 percent and 1.3 percent, respectively, which was slightly less than last month for each segment.

The complete blog entry can be read here.