Autonomous-drive cars further off than most expect

Despite near constant chatter about self-driving vehicles revolutionizing how the world gets around, a new report says the transformation will take longer than many have predicted.

"The reality is autonomous-drive cars will not reach large numbers until close to 2040," said Hans-Werner Kaas of McKinsey. Kaas has written a new study looking at the expected development and impact of self-driving vehicles. "The hype is getting ahead of the reality."

Kaas sees autonomous drive technology being quickly developed, but expects implementation to be more gradual than many have predicted.

Several automakers, including General Motors, Tesla and Audi have announced plans to sell vehicles in the next couple of years with auto pilot systems that will allow cars to control their speed and steering on highways.

Beyond that, the development of truly autonomous drive vehicles will take another 15-20 years according to the McKinsey report.

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"We see this technology coming in three waves," said Kaas. "For many years there will still be many vehicles on the road that won't be communicating with autonomous drive vehicles, so the transition will take time."

Once sales of self-driving cars and trucks takes off, Kaas says they will have a major impact.

* An estimated 1.2 billion motorists around the world who spend 50 minutes per day in traffic will find themselves with freed up time.

* Drivers of autonomous drive vehicles will be free to use their commuting time to use the Internet. McKinsey estimates for every additional minute people spend on the mobile internet while in the car, digital media revenues will grow by five billion euros every year.

* Up to 5.7 billion square meters of parking space could be saved in the USA by 2050 as autonomous drive cars lead to more ride sharing.

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As for who will lead the development of autonomous drive vehicles, Kaas believes many premium automakers may be in the best position right now. However, McKinsey sees a number of tech firms also playing major roles in the race to build self-driving vehicles.

Questions? Comments? BehindTheWheel@cnbc.com .