This was the year that U.S. auto sales were supposed to tank after six straight year-over-year increases. Like Brexit and Hillary Clinton's presumed cakewalk to the White House, auto sales in 2016 have confounded the experts.

Sales for the month of November came in strong for General Motors  (GM - Get Report) , Toyota Motor  (TM - Get Report) and Ford Motor   (F - Get Report) , while Fiat Chrysler Automobiles N.V. (FCAU - Get Report) posted a big decline. Overall, the industry is expected to register a seasonally-adjusted average rate (SAAR) of 17.9 million vehicles for the month or close to it.

Just as pollsters and journalists clearly underestimated U.S. voter disappointment with establishments of both political parties this election year, analysts may have underestimated U.S. consumer optimism -- an important indicator that signals the willingness to finance a new vehicle or a new home.

And this unexpected trend may continue for a while: Mustafa Mohatarem, GM chief economist, said "the U.S. auto industry is well positioned for sales to continue at or near record levels into 2017."

Automakers have been boosting discounts and financial incentives, hoping to stimulate demand and keep sales going. As has been the case all year, sales of crossovers, SUVs and pickups were especially strong, driven by relatively cheap fuel prices. With one month left to go in 2016, a strong December could break last year's record 17.5 million vehicles sold.

GM sales for the month were up 10.2%; Ford's were up 5.1%; Toyota gained 4.3%; Nissan Motor  (NSANY) sales rose 7.5% and Honda Motor  (HMC - Get Report) sales were up 6.5%. Fiat Chrysler fleet sales were down 42%, leading to a 14% overall decline.

Despite the rising discounts, average vehicle transaction prices also continued on the rise, reflecting the larger, more powerful and feature-laden models that consumers were choosing.

"Climbing transaction prices reflect the shift in consumer preference from cars to more expensive trucks and SUVs," said Tim Fleming, analyst for Kelley Blue Book. "Manufacturers with strong truck and SUV lineups are currently seeing record pricing, especially in these late fall months when these segments are especially popular."

The average transaction price for November was $34,948, up $581 from a year ago, according to Kelley Blue Book.

At the beginning of the year, analysts had been forecasting a year that would be even with 2015 or slightly down. Mike Jackson, chief executive of AutoNation  (AN - Get Report) , the nation's biggest retailer, said sales were hitting a "plateau." Mark Fields, chief executive of Ford, echoed Jackson's sentiments.

With oil prices possibly headed higher in light of possible production cuts by OPEC, gasoline prices could be going up again. Higher prices at the pump could finally pinch off consumer enthusiasm, as could higher interest rates if the Federal Reserve tightens monetary policy in light of the latest economic growth numbers.

The auto industry's cyclical nature remains a constant, though year's worth of short-term predictions for a turn in the market aren't looking very prescient today.

Doron Levin is the host of "In the Driver Seat," broadcast on SiriusXM Insight 121, Saturday at noon, encore Sunday at 9 a.m.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.