Automakers on Tuesday set a new US sales record for 2015 even as December sales fell short of expectations, and most forecasters said sales should rise to another record this year.

For full year 2015, US sales hit a record of 17.47 million vehicles, breaking the mark of 17.41 million vehicles in 2000, according to Autodata Corp. Low gasoline prices, easy credit and moderate economic growth boosted the industry.

WardsAuto, which provides data used by the US government for economic analysis, said 2015 sales set a record at 17.39 million vehicles sold, breaking the 2000 mark of 17.35 million.

Autodata said December sales rose 9 per cent. On an annualized rate, accounting for seasonal factors, December sales were 17.34 million vehicles, well below the 18.1 million vehicles expected by a Thomson Reuters poll of 38 economists and analysts.

“The US economy continues to expand and the most important factors that drive demand for new vehicles are in place, so we expect to see a second consecutive year of record industry sales in 2016,” said Mustafa Mohatarem, chief economist for General Motors).

Mohatarem said the most important factors are employment and growth in personal income, which will remain strong this year.

Some forecasters, including TrueCar Inc, said US sales will hit 18 million vehicles this year. The Federal Reserve's recent interest rate increase should not deter sales.

"Interest rates would have to reach 3 per cent next year before we see an inflection point that causes the year-over-year growth rate to stagnate," said TrueCar's chief economist, Oliver Strauss.

Mark Wakefield, leader of the auto practice at AlixPartners, predicted that sales will peak in 2016, at 17.75 million vehicles. Wakefield said sales will then decline to 17.4 million in 2017, 16.1 million in 2018 and 15.2 million in 2019. He said they would then gradually rise to 17 million in 2022.

Wakefield said in an interview that a century of data, along with factors such as a glut of quality used vehicles, pointed to a moderate downturn that will begin to be felt in 2017.

He said 800,000 more used cars will be available this year than in 2015.

The industry has steadily recovered since 2009, when sales hit 10.4 million vehicles, the lowest level since World War Two, adjusted for population.

In December, GM, the top seller in the United States, said its sales rose 5.7 per cent from a year ago. Ford Motor Co, the No. 2 US automaker, reported a jump of 8 per cent.

Sales of Ford's F-Series pickup truck rose 15 per cent in December. The F-Series, led by the F-150 pickup, extended two streaks: 39 years as the best-selling truck in the United States and 34 years as the best-selling vehicle of any kind.

US consumers continued to shift from cars, including sedans and hatchbacks, to SUVs, crossovers and trucks. Low gasoline prices and better fuel economy for larger vehicles encouraged this trend, said Mark LeNeve, head of Ford's US sales.

At GM, car sales fell 14.2 per cent in 2015 while sales of trucks, crossovers and SUVs rose 16.3 per cent.

GM car sales were at their lowest share of US sales, 30.2 per cent, in 2015, down from 37 per cent in 2014. Before 2000, cars never accounted for less than half of US sales.

Toyota Motor Corp, third in US sales, had a gain of 11 per cent. Honda Motor set an annual record for US sales at 1.59 million vehicles, up 3 per cent. Honda's December sales rose 10 per cent.

Sales rose 13 per cent at Fiat Chrysler Automobiles and 19 per cent at Nissan Motor Co Ltd in December.

Hyundai Motor sales fell 1.5 per cent as its US production is constrained by capacity.

Volkswagen AG's VW brand sales fell 9 per cent in December after a 25 per cent drop in November as the company's diesel emissions scandal pressured performance.

Daimler AG's Mercedes-Benz took the annual luxury sales crown, with sales of 372,977, up 5 per cent, while BMW sales of 346,023 rose 2 per cent.

Toyota's Lexus brand, which was the US luxury sales leader before the 2011 earthquake and tsunami in Japan, was right behind BMW, at 344,601 vehicles sold, up 11 per cent. – Reuters