With part of the new-model sales prediction chatter associated with the Volkswagen diesel controversy, a pair of used-vehicle sales projections indicated that side of the market should top 3 million in September.

The analysts at TrueCar are even more optimistic, thinking total used-vehicle sales — including franchised and independent dealership turns and private-party transactions — may exceed 4,328,643 units. Should the market hit that figure, it would represent a 3.2 percent gain year-over-year.

Edmunds.com also offered a used-vehicle sales forecast for this month, but analysts there are projecting sales won’t be that high in September. The site reported an estimated 3.01 million used vehicles will be sold in September for a seasonally adjusted annual rate of 37.5 million. That’s compared to 3.21 million — or a SAAR of 36.7 million — used-vehicle sales in August.

More industry observers offered their takes on what the new-model sales market might do this month, and many touched on the impact the VW leadership shakeup might do.

“Volkswagen’s deception is dominating headlines, but it is not keeping shoppers away from other brands’ showrooms,” said Edmunds.com director of industry analysis Jessica Caldwell, who put the site’s new-car sales forecast at 1,415,436 units to be sold in the U.S. in September for an estimated SAAR of 17.8 million.

“It puts the crisis in a little bit of perspective, since these Volkswagen diesels don't constitute a very big share of sales,” Caldwell continued. “It’s also a reminder that buyers won’t disappear from the market just because they suddenly can't or don't want to buy these affected cars. They're willing to turn to other automakers that will meet their needs.”

Edmunds’ new-sales prediction would represent a 10.1-percent decrease from August but a 13.9 percent increase from September of last year. However, the site’s projection would make this month’s sales volume the biggest September since 2004, and the sales rate will be the biggest September SAAR since 2000.

Back at TrueCar, analysts are projecting the new-car SAAR should reach 17.7 million units in September versus 16.5 million units a year ago, the highest in more than a decade, led by robust retail sales.

“Labor Day and model year-end promotions combined to create an impressive outcome this month,” said Eric Lyman, TrueCar’s vice president of industry insights. “September’s sales pace underscores the strength of the auto sector’s continued expansion and our confidence that full-year sales will reach 17.2 million units in 2015.”

TrueCar added that Volkswagen may be an outlier this month, following news that software on the automaker’s diesel models was altered to allow the vehicles to pass emissions tests. Sales of TDI diesel models have been suspended, and analysts noted that VW’s volume may fall 5.2 percent in September.

“With 27 percent of VW sales coming in the form of TDI-equipped cars, we expect an immediate impact on the brand until the stop-sale on TDI vehicles ends,” Lyman said.

Kelley Blue Book analysts shared that they expect new-vehicle sales to increase 12 percent year-over-year to a total of 1.39 million units in September 2015, resulting in an estimated 17.5 million SAAR.

At 1.39 million units, KBB said this will be the highest September sales volume since 2006.

Kelley Blue Book senior analyst Alec Gutierrez noted that dealers should expect big increases across the industry in September, with the average gains from manufacturers in the double digits. 

Including Labor Day sales with September totals this year is one reason for the big jump, but Gutierrez explained the underlying demand for new vehicles remains strong.  With the average age of vehicles on the road increasing, used-car prices on the rise and financing still inexpensive, he said it looks like new-car sales will continue to increase in the near future.

"While the Volkswagen scandal will have a negative impact on sales, the affected models represent less than a quarter of their portfolio, and some dealers have already depleted their stock of those units,” Gutierrez said.

“The larger issue is the hit the automaker's brand image and perceived trustworthiness, which may affect sales of their other models,” he continued. “We think the effects on September sales won't be too bad for Volkswagen Group's combined sales, but October and beyond could be another story.”

Finally, the monthly sales forecast developed jointly by J.D. Power and LMC Automotive has September with a new-vehicle sales total approaching 1.2 million units, a 10.2 percent increase on a selling-day adjusted basis compared with September of last year, and the strongest sales volume for the month of September since 2004 when sales reached 1.2 million units.

The forecast from J.D. Power and LMC Automotive pegged the SAAR for September reaching 14.9 million units, an increase of 1.2 million units from the selling rate last September and the highest for any month since July 2005

“Having Labor Day sales count in September definitely gives the month a tremendous lift,” said John Humphrey, senior vice president of the global automotive practice at J.D. Power. “On a selling-day adjusted basis, sales through the Labor Day weekend were 72 percent stronger than the same time last year.”

As a result of the vigorous selling pace during the spring and summer months — the selling rate from May through August averaged 17.5 million units — LMC Automotive is raising its 2015 total light-vehicle sales forecast to 17.2 million units from 17.1 million units and its retail light-vehicle forecast to 14.1 million units from 14.0 million units.

“The Federal Reserve’s decision to keep interest rates at the current level paves the way for the U.S. auto market to post strong results for the remainder of 2015, as the primary risk to volume — a rate increase — is likely pushed out to December or early 2016,” said Jeff Schuster, senior vice president of forecasting at LMC Automotive.

“Sales the previous three months have significantly exceeded expectations, so if interest rates remain low, auto sales in 2016 will get a further boost from an economy that should accelerate,” Schuster added.