<p><em><strong>Photo of 2015 Chevrolet Silverado LTZ courtesy of GM.</strong></em></p>

Vehicle manufacturers should sell 16.5 million light-duty vehicles in retail and fleet channels in 2014, which represents a 6 percent increase from 2013 amid the backdrop of an improving U.S. economy, according to Edmunds.com.

Spending on U.S. vehicles should reach $100 billion for the year. In 2013, buyers spent $90.8 billion on light-duty vehicles, Edmunds.com projects.

In December, 1.51 million vehicles will be sold. This represents a 16.4 percent increase from November and an 11.4 percent increase from December of 2013, according to the company.

"Many factors have helped car sales recently," said Jessica Caldwell, senior analyst with Edmunds.com. "Low gas prices, a record stock market and the improving economy are making people feel more financially comfortable, and even the weather has cooperated, for the most part."