Edmunds.com, the leading car information and shopping network, forecasts that 1,537,436 new cars and trucks will be sold in the U.S. in May for an estimated Seasonally Adjusted Annual Rate of 17.5 million. The projected sales will be a 2.3 percent increase from April 2016, but a 5.8 percent decrease from May 2015. While sales appear to be slowing, Edmunds says that 2016 is still on track to break last year's record of 17.47 million new car sales.

"It's easy to look at May's sales and conclude that the retail car market is losing steam, but it's too soon to say for sure that auto sales are leveling off," says Edmunds.com Director of Industry Analysis Jessica Caldwell. "As in previous years, the summer months will flush out more incentives from automakers and the urgency that shoppers show in responding to these incentives will give the industry a much better sense of how the market is trending."

Edmunds.com estimates that retail SAAR will come in at 14.3 million vehicles in May, with fleet transactions accounting for 18.5 percent of total sales. An estimated 3.2 million used cars will be sold in May, for a SAAR of 38.5 million (compared to 3.4 million – or a SAAR of 38.5 million – used car sales in April).