An existential threat to the auto industry

U.S. auto sales may have hit a record last year, but a newly released study shows such records may soon be harder to set. It found a decline in the number of younger people getting drivers' licenses, suggesting American attitudes on conventional car ownership are shifting and leading to profound changes in the auto industry.

The University of Michigan survey, which looked at licensing trends from 1983 through 2014, found a continuous decrease in the percentage of those under age 45 who hold a driver's license.

But it isn't just younger generations who have soured on the idea of driving. University of Michigan researchers Michael Sivak and Brandon Schoettle found that since 2008, the percentage of Americans with drivers' licenses in nearly every age group has declined, even as U.S. auto sales have slowly regained the robust levels recorded before the Great Recession.

In fact, the only group to see an increase were those aged 70 and older.

These changes and others revealed in the study portend "potentially major implications" for the transportation industry, including the number of vehicles purchased, Sivak said.

Though auto sales climbed to 17.5 million last year, industry analysts believe they may soon peak -- if they haven't already. The specter of stagnating auto sales looms even as the age of U.S. auto fleet continues to climb and the nation's population grows, surging 14 percent since 2000, when auto sales hit a previous high of 17.4 million.

Sivak and Schoettle didn't speculate about what's behind the drop in Americans' desire to drive, but several trends could explain why the love affair with the car may be flagging.

First, living in big cities is hot again -- especially among millennials -- and many people find that driving (and owning) a car, say, in New York or San Francisco, is more hassle than it's worth, especially when there are more convenient ways of getting around, including subways, buses and trains.

Online shopping has also reduced the need to drive, allowing consumers to have many of the goods they need delivered right to their doorstep, rather than having to venture out and pick them up.

But it's the popularity of ride-sharing services such as Uber and Lyft, which provide yet another way of forgoing the need to drive oneself here and there, that have grabbed the attention of automakers, which see opportunity in developing self-driving cars.

Earlier this month, General Motors (GM) invested $500 million in Lyft to develop a network of self-driving cars that riders can call up on-demand, a goal shared by rival Uber and Alphabet (GOOGL), the parent of Google.

As a follow-up, this week, the Detroit-based automaker announced it had acquired the technology and most of the assets of the San Francisco-based ride-hailing pioneer Sidecar Technologies in a big to help GM strengthen itself against the rising popularity of Uber.

The moves give GM a leg up on competitors such as Daimler and Ford Motor (F), which are developing their own ride-sharing services.

If GM and the rest of the auto industry are successful in integrating the new transportation options that many Americans find appealing, they might just weather the trend of waning interest in driving and find a new highway to growth.