Just a couple of years ago, self-driving cars were the stuff of science fiction, their availability for average drivers always decades away. But with Google leading the autonomous-vehicle charge, technically as well as legally -- and recently announcing intentions to partner with the auto industry -- self-driving cars could be here earlier than anyone ever thought.

That’s also the conclusion of a report released last week by the respected market-research firm KPMG and the Center for Automotive Research. The report even went as far as to say that the impact of autonomous driving on the automobile industry -- as well as on transportation and society as a whole -- will be as significant as Henry Ford’s introduction of the assembly line. It cites four trends that researchers see as speeding up the development of self-driving cars.

One Detroit automaker is already rapidly moving ahead with self-driving technology and will have partially autonomous cars by the middle of the decade. And as with Google, the company's goal is more about safety than convenience and technical know-how.

The four trends that the report says will accelerate autonomous cars include:

Market dynamics: Licensing for young drivers is dropping significantly, as a new tech-savvy, social-media-connect​ed generation is steering away from the U.S.’s long love affair with cars. This also coincides with projected increases in urban populations, and subsequent traffic congestion, that will change how people view transportation -- and may alter the dominance of the automobile.

Adoption: The shift to autonomous cars will, of course, depend on factors such as cost, legislation and availability as well as how they would travel along with the millions of older cars still on the road. On the last point, a "base case" scenario outlined by the study predicts that autonomous vehicles could be given their own lanes or could use existing car-pool lanes, which would ramp up adoption.

Implications for investment: This considers the economics side of the trend. Fewer accidents mean fewer traffic jams and possibly greater productivity. Also, car-sharing could become more common, creating less demand for car ownership -- meaning fewer vehicles sold.

Convergences: This is the part of the trend toward autonomous driving that you can actually try for yourself if you’re shopping for a new car. Driver-assist technologies such as adaptive cruise control and lane-departure prevention take temporary control of the car to prevent accidents, and are becoming more common. They are paving the way for self-driving cars.

Building on some of these systems, General Motors' Cadillac division is already on track to deliver a semiautonomous driving feature called Super Cruise to the market by 2015. It will take the sensor compatibility used by technologies that are part of the Driver Awareness package on the Cadillac XTS and the upcoming ATS and combine it with two new driver-assist systems: full-speed range-adaptive cruise control and lane centering.

“Lane centering keeps the vehicle centered within the roadway,” GM spokesman Dan Flores told Exhaust Notes. “That will be combined with full-speed range-adaptive cruise control that keeps a safe distance from cars in front of you -- from the speed limit all the way down to a complete stop.”

But Super Cruise -- as with autonomous driving in general -- doesn’t mean you’ll be able to check out behind the wheel, just as pilots have to remain vigilant when flying on autopilot. And the goal is not technology for technology’s sake, Flores added.

“From a GM perspective, the basis of all this technology is not to get us to autonomous vehicles,” he said. “The focus is we want to create cars that ultimately don’t crash. And once you get to a point where cars don’t crash, it’s a very small step to get vehicle to drive themselves.”

Doug Newcomb has been covering car technology for more than 20 years for outlets ranging from Rolling Stone to Edmunds.com. In 2008, he published his first book, "Car Audio for Dummies" (Wiley). He lives and drives in Hood River, Ore., with his wife and two kids, who share his passion for cars and car technology, especially driving and listening to music.