ATLANTA -

Spurred by high demand and shrinking supply, asking prices for certified pre-owned vehicles surged in July, according to AutoTrader.com, which saw a year-over-year price bump in 17 of the site’s 20 most popular CPO models during July.

What’s more, 13 of those increases were greater than $1,000.

The CPO price hike was particularly evident at Toyota and Honda. Between the two automakers, there were 10 CPO models whose prices climbed more than $1,000.

In fact, three showed gains of more than $2,000, those being the certified editions of the Toyota Highlander (up $2,412), Honda Accord (up $2,075) and Toyota 4-Runner (up $2,012).

But CPO models weren’t alone in their asking price increases.

Twelve of the 20 most popular used models on AutoTrader.com were up in price from July 2010, as were 14 of the top 19 new rides (there is no year-over-year data available for the Chevrolet Cruze).

“The combination of consumers holding on to their cars longer, leasing drying up and the lack of new car sales in 2009 and 2010 has caused a dearth of late-model quality used cars being available for sale in 2011,” explained Rick Wainschel, vice president of automotive insights at AutoTrader.

“This short supply has put tremendous pressure on the used and CPO market, pushing prices higher,” he added. “Additionally, production shortages in the new car arena have had a similar effect.”

On the used-car side, the gains were heftiest in small-car segments like compacts and midsize sedans, AutoTrader noted. The two compacts (Honda Civic and Volkswagen Jetta) and two midsize sedans (Accord and Nissan Altima) on the list of 20 most-researched used rides all saw their prices go up more than 10 percent, as these four models led the year-over-year price increases.

For new vehicles, nine of the 14 units showing price gains were up at least $1,000.

Which Vehicles Are Consumers Researching?

Moving along, AutoTrader also shared which used, CPO and new vehicles are generating the most attention from shoppers on the site.

What AutoTrader discovered is that in the midst of eased, but still expensive gas prices, shoppers “continued to flock toward big trucks and SUVs.”

While the near-$4/gallon fuel costs may have briefly deterred shoppers from these segments earlier this year, that aversion appears not to have lasted thanks to some alleviation in fuel costs during June and steadiness last month.

“Every time gas prices start increasing, there’s a threshold at which consumers start focusing more on fuel efficiency than other considerations; however, that threshold becomes a moving target with each major increase, as shoppers’ tolerance for what they pay at the pump eventually goes up,” Wainschel explained.

The used market, in particular, showed several full-size trucks making gains in consumer interest from June, with popularity waning for small cars and luxury cars, AutoTrader noted.

The Dodge Ram 1500, Chevrolet Silverado 2500 and Dodge Ram 2500 each came in two spots higher on AutoTrader’s used-vehicle popularity rankings than where they were in June. However, three of the four luxury cars on the list (Infiniti G35/37, BMW 5-Series, Audi A4) dropped two spots.

The Civic and Accord were the other two decliners from June, with the Civic dropping from No. 8 to ninth and the Accord sliding from No. 7 to No. 8.

The CPO trends were a bit more of a mixed bag, as full-size trucks and SUVs were largely static. AutoTrader spotted just “a few standouts” among the crossovers, like the certified Honda Pilot’s ascension from No. 16 to No. 13.

Meanwhile, on the new-car list, 12 of the top 20 most-researched vehicles were either full-size trucks or SUVs. Interestingly enough, the vehicle making the furthest leap was the Kia Sorento, a crossover that jumped from No. 27 to No. 20.

The site found that interest in new compacts faded compared to June.

AutoTrader provided the following charts to better illustrate the data: