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Google has been making enough progress with its self-driving cars that it believes it could be ready for broad-scale use within five years.

Chris Urmson, the head of the Google project, also has a very personal reason for that time frame. He has an 11-year-old son that, absent self-driving cars, will be eligible to get his driver’s license in about four and a half years.

“My team and I are committed to making sure that doesn’t happen,” he said, speaking Tuesday at the TED conference in Vancouver.

Urmson said Google believes that while technology that assists drivers can help reduce some accidents, only completely self-driving cars will fully address safety concerns. One reason, he said, is that the better the assistive technology gets, the more risks human drivers will take.

Nor, he said, will today’s driver-assist technologies just evolve to become fully self-driving cars on their own.

“That’s like me saying if I work really hard at jumping, one day I will be able to fly,” he said.

Google initially had a model with a steering wheel to allow humans to take over if need be, but its current design — unveiled at last year’s Code Conference — is fully self-driving.

The company is currently logging three million miles in simulators every day, in addition to its real-world driving tests. Urmson showed how the vehicle can handle complex occurrences like traffic zone lane closures, a bike running a red light and even a woman in a motorized wheelchair chasing ducks.

Here are our own Kara Swisher and Liz Gannes taking the car for a joy ride:

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