The US has become a nation of ancient pickup trucks

If you want to know why the Big Three Detroit automakers - GM, Ford, Fiat-Chrysler - are selling so many pickup trucks and banking the profits from these all-American vehicles, look no further than a simple statistic.

Vehicle age.

The average age of a vehicle on the US road is more than 11 years.

That's practically unprecedented, a hangover from the financial crisis, and a big driver of booming car sales in 2014 and 2015.

Americans don't drive old cars. But for years, they have been, hemmed in by a weak economy, job losses, and tight credit.

The situation is even more stunning on the pickup-truck front.

According to Ford CEO Mark Fields, 50% of the pickups in the US fleet are 10 years old or older.

And 25% are 20 years old or older. (Fields remarked on the age of US pickups during the Ford's third-quarter earnings call on Tuesday.)

America has become the home of the free and the land of the totally beat-to-crap truck.

That's good news for Ford.

The automaker builds the F-150 full-size pickup, which for decades has been the bestselling vehicle in the US.

And after taking a big risk by reengineering the mighty F-Series to include more lightweight aluminum, Ford is ready to sell a brand-new truck to all those people whose old F-150 is celebrating a 20th birthday.