IRVINE, Calif. -

It hasn’t happened since April: auction values for affordable small cars climbing.

But that’s exactly what Kelley Blue Book observed recently.

Thanks to a modest increase in price at the pump, used vehicles such as the Honda Fit, Smart fortwo, Suzuki SX4, Volkswagen Jetta TDI, Kia Rio and Honda Insight posted $100 to $600 price gains during the four weeks leading up to this past Thursday, KBB’s Alec Gutierrez said in a recent analysis.

While current uptick in fuel costs is rather modest and likely won’t last long, this hasn’t kept a few dealers from snagging the more inexpensive fuel sippers in the lanes, he noted.

“A jump in fuel prices nearly always precedes a rise in values of fuel-efficient vehicles,” said Gutierrez, KBB’s senior market analyst of industry insights. “However, we usually do not see a quantifiable increase in demand until gas prices approach $3.75 per gallon or more nationally.

“Despite the 7-cent per gallon increase in fuel prices so far this month, prices remain 50 cents below their April peak of $3.92 per gallon and are due for further declines later this year,” he continued.

“If seasonal patterns hold true, the current upswing in fuel prices likely will be short lived and relatively modest overall,” Gutierrez shared. “Yet some dealers have taken the opportunity to buy the most affordable fuel-efficient vehicles at auction, perhaps anticipating an uptick in demand for fuel-sippers from price-sensitive shoppers.”

Even amid “isolated pockets of strengths” in the wholesale arena, used values in the aforementioned four-week span fell an average of 2.2 percent, Gutierrez said. And fuel-friendly subcompact, compact and hybrid cars had the steepest slide, as they softened between 2 percent and 4 percent.

“There is a small chance that the price increases we have seen over the past several weeks could signal the beginning of a turnaround in auction values; however, it is far more likely that the isolated gains today are anticipated, rather than actual, increases in consumer demand for fuel-efficient vehicles due to rising fuel prices,” the analyst emphasized.

As of Thursday, the national average for fuel cost was less than $3.50 per gallon, he added.

Gutierrez also pointed out the U.S. Energy Information Administration’s projections for a continue slide in gas prices the remainder of the year and into next year.

Citing the EIA’s July 10 short-term energy outlook, he said fuel consumption went down significantly last year, noting that Americans are using less fuel in 2012, as well.

“An increase in the fuel-efficiency ratings of vehicles sold over the past several years, coupled with a high unemployment rate that has kept drivers off the road, sent consumption tumbling by 340,000 barrels per day in 2011, and another 150,000 barrel-per-day decline is expected in 2012,” Gutierrez pointed out.

“After factoring in rising production levels and record high crude inventories, it is no wonder the EIA has projected fuel prices to average $3.49 per gallon in 2012 and only $3.28 per gallon in 2013, down from an average of $3.52 in 2011,” he added.

What’s more, the proportion of consumers anticipating "somewhat higher"  gas prices dropped from 61 percent in the first quarter to 37 percent in the second, the analyst said, citing KBB Market Intelligence.

More than half (55 percent) are expecting fuel costs to drop or remain steady.

“With fuel prices expected to continue to decline, Kelley Blue Book believes that although we may see isolated pockets of strength in values of fuel-efficient vehicles from time to time, these values will continue to trend downward through the rest of the year,” Gutierrez concluded.