U.S. auto makers will sell more cars and light trucks in May than in any month since August 2007, according to a new WardsAuto forecast.

With daily sales projected to hit a 57-month high of 54,250 units over May’s 26 selling days, the report calls for the industry to deliver 1.41 million light vehicles during the month.

The May forecast represents a 10.2% increase over April’s DSR (24 selling days), in line with recent April-to-May increases that have averaged 11%.

It also marks a 20.3% jump from May 2011’s DSR (24 days), a period that saw steep sales declines due to depleted inventories in the wake of the March 2011 earthquake and tsunami in Japan.

Those inventory droughts persisted into the fall – particularly at Toyota and Honda – and will continue to factor into large year-over-year growth rates for the next several months.

Forecast sales equate to a seasonally adjusted annual rate of 14.56 million units, which, combined with April’s 14.4 million SAAR, would maintain the year-to-date annualized rate of 14.5 million units.

The projected May sales also would bring year-to-date deliveries to 6.05 million, up 15% from year-ago.

While the overall economy is growing at a much slower-than-expected pace, the auto industry should continue to see double-digit expansion for the rest of the year.

Although the Conference Board Consumer Confidence Index declined slightly in April from March, to 69.2 from 69.5, the Present Situation Index, a better indicator in recent months of the car-buying public’s mood, improved to 51.4 from 49.9.

Bureau of Labor statistics show unemployment fell to a 39-month low of 8.1% in April, continuing a slow-but-steady decline that should bode well for auto sales.

Almost all auto makers have aggressive incentive plans in place, which should play a significant role in pushing sales higher than they’ve been in nearly five years.

The Detroit Three account for 45.3% of May’s forecast light-vehicle deliveries. Both General Motors and Chrysler are projected to take roughly the same share of the market as in April, with GM grabbing 18.1% and Chrysler 11.8%.

Ford should boost its take from 15% in April to 15.4% in May, bumping Toyota out of the No.2 spot gained last month for the first time in 21 months.

It will be a close race, though, with Toyota projected to sell 214,000 vehicles, or 15.2% of May deliveries, as the auto maker continues to ramp up production and incentives in an attempt to regain its pre-recession market position.

Honda had a strong April, controlling 10.3% of LV sales. But while WardsAuto looks for the auto maker to achieve its highest DSR since August 2008, Honda still may not have the inventory to pull down much more than a 10% stake in May.

Hyundai Group, which was largely immune to last year’s production interruptions, will see year-over-year growth nearer to 3%, but account for more than 8% of LV sales nonetheless.

Rounding out the top seven auto makers, Nissan, which historically registers large gains in daily sales from April to May, is expected to see its DSR jump 27% from prior month, and 19.7% over year-ago, good for a 7% share.

jsousanis@wardsauto.com