"Peak oil" is the term given to the date after which extraction and production of oil enters terminal decline.
It doesn't mean the oil is necessarily running out--more that its extraction becomes less viable as time goes on.
Some suspect a similar thing is happening with automobile use in the U.S, as running a vehicle gets more expensive and cars themselves become niche items, rather than a primary means of transportation.
That's unlikely to happen for a while yet, but the early signs are there.
Navigant Research cites a report (.pdf file) by the University of Michigan Transport Research Institute (UMTRI) which finds an increasing number of U.S. households are carless.
It's been a measurable trend since 2007, and reached a 9.2 percent total in 2012. In some areas of the country, the rate at which fewer are owning cars is even higher--in the Detroit metro area, that figure has increased five percent.
Such statistics follow others suggesting younger buyers are less interested in cars than they are their smartphones, leading to fewer millennials, customers born between the early 1980s and early 2000s, buying fewer cars than their parents or grandparents did.
The elephant in the room is the global financial crisis of 2007-2008 that caused a huge recession--conveniently concurrent with the period in which people have bought fewer cars.
MORE: Oil And Energy: Bountiful Or Dwindling? Experts Argue
Higher costs of living and greater employment are hardly catalysts for carefree spending, but it could be said the recession has caused some to re-prioritize their purchases--and cars may be seen as collateral damage by some.
Alternatively, they may be seen as more of a luxury item or a hobby.
Navigant cites another report by J.D. Power, in which young buyers particularly want their cars to "stand out", and buyers are particularly keen on driving on "challenging roadways with hills and curves".
We're not sure there's a time when that hasn't been the case for younger drivers, but those still able to afford vehicles may be placing more emphasis on the fun, rather than the necessity of driving.
A paradigm shift in car ownership can only really occur when sufficient public transit alternatives become available, which they aren't for many Americans.
But if such a shift occurs, suggests Navigant, the next 30 years could reveal a market where cars are--like the horses they replaced--a source of pleasure and entertainment, rather than mere transport.