DETROIT — Unexpectedly strong sales of new vehicles in the United States in December propelled the industry to another record figure in 2016: 17.55 million sold.

That is the good news.

The bad news, though, is that the late push to beat the previous record, 17.47 million vehicles sold in 2015, came at a steep cost, as companies piled on higher sales incentives to lure consumers to their showrooms.

And with the American market tilting more than ever toward sales of pickup trucks and sport utility vehicles, companies are cutting production of passenger cars to reduce big inventories of slow-selling models.

As a result, there is little expectation that the sales will continue on this upward trajectory — at least not without cutting deep into profits. That means the numbers released Wednesday could be the high-water mark for the industry’s impressive comeback from the depths of the recession, when annual sales fell below 11 million vehicles and General Motors and Chrysler needed government bailouts to survive.