Edmunds forecasts that 1,565,683 new cars and trucks will be sold in the U.S. in May for an estimated seasonally adjusted annual rate (SAAR) of 16.7 million. This reflects a 16 percent increase in sales from April 2018 and a 3.5 percent increase from May 2017.

"The summer selling season is off to a healthy start," said Jeremy Acevedo, Edmunds manager of industry analysis. "Despite rising gas prices, shoppers are clearly demonstrating their confidence in the strength of the economy as they continue to seek out larger, more expensive vehicles."

Edmunds experts note that Memorial Day sales events could contribute to this lift as well.

"Inventories of in-demand vehicles such as light trucks are still running high, so automakers are motivated to make this holiday weekend sales event count," Acevedo said. "Depending on how shoppers respond, this could set the trend for even sweeter deals as we head deeper into the year."

SALES VOLUME FORECAST, BY MANUFACTURER

Edmunds estimates that retail SAAR will come in at 13.6 million vehicles in May 2018, with fleet transactions accounting for 18.5 percent of total sales. An estimated 3.4 million used vehicles will be sold in May 2018, for a SAAR of 39.3 million (compared to 3.5 million — or a SAAR of 39.2 million — in April).

MARKET SHARE FORECAST, BY MANUFACTURER