Edmunds, the leading car shopping and information platform, forecasts that 1,597,256 new cars and trucks will be sold in the U.S. in March for an estimated seasonally adjusted annual rate (SAAR) of 16.9 million. This reflects a 23.2 percent increase in sales from February 2018 and a 3.0 percent increase from March 2017.  

"Healthy first-quarter numbers indicate the industry is on solid ground, but that doesn't mean we can expect another banner year for new car sales," said Jessica Caldwell, Edmunds executive director of industry analysis. "Though March tends to be a prognosticator for the year as a whole, if automakers remain disciplined with incentives and further rein in spending, we could potentially see sales start to tumble in the high-volume summer months when shoppers aren't seeing the deals they are looking for."

Edmunds estimates that retail SAAR will come in at 13.3 million vehicles in March 2018, with fleet transactions accounting for 21.4 percent of total sales. An estimated 3.7 million used vehicles will be sold in March 2018, for a SAAR of 39.3 million (compared to 3.5 million — or a SAAR of 39.1 million — in February).