As one of the great innovators of Silicon Valley, Google is known for regularly testing the waters with unorthodox ideas that appear to have little to do with the company's core business. In just the past two weeks, the company has announced a $280 million solar power initiative and is in the process of conducting a new Google Ideas conference for political extremists to discuss the role that technology can play in de-radicalization efforts around the globe. That’s what you do when you have the constant need to discover the next big trillion-dollar market idea.

The latest big Google idea? Driverless cars.

With the help of Google lobbyists, the Nevada legislature passed Bill 511 this past weekend, which essentially legalizes the operation of driverless vehicles on highways within the state of Nevada. (Yes, that's one more thing you can do in Vegas that you can't do in the rest of country.) Far from being a publicity stunt or side project of a fabulously wealthy executive, this appears to be part of a broader strategic vision within Google. At Cannes last week, for example, Google chairman Eric Schmidt outlined his two big ideas for the year - one of them was mobile payments on Android phones, and the other was driverless cars.

The meme of driverless cars really took off earlier this year, when Google's Sebastian Thrun gave a brilliant TED Talk on his vision for the future of these vehicles. These driverless vehicles use laser range finders and video cameras to detect traffic and possible obstacles, and then navigate their way using detailed maps. Watching videos of these cars in action is impressive: they've already been driven more than 140,000 miles in California, including urban streets, mountain roads and obstacle test courses (where speeds approach 45-50 mph). These driverless vehicles could eliminate traffic congestion, reduce the number of traffic fatalities by half each year, and help save the environment by cutting down on the amount of air pollution.

Yes, but is it really a trillion-dollar market opportunity for Google?

The speculation about Google’s plans for the cars runs the gamut, with most people assuming that the company is just looking for another way to monetize your 52 minutes of commuting time each year. After all, if you’re not behind the wheel and stuck in traffic, you could be making Google search inquiries, clicking on Google text ads, or downloading new Google docs.

More likely, however, Google has realized that the line between the physical world and the Internet world continues to blur. Soon, there will be no such thing as an "online" business or an "offline" business, or a "mobile" business and an "Internet" business. What if the Google Car is the precursor of an online collaborative sharing service like Getaround or Zipcar? That could be a big idea that blends elements of mobile, digital and social networking with the basic structure of a mainstream car rental business.

Even before the driver-less car meme started to take hold this year, it was becoming clear that the modern car is as much a computer – with on-board satellite navigation systems and sophisticated entertainment systems - as it is a means of transportation. We've already heard stories about luxury cars that enable on-board computer systems to do the parallel parking for their drivers.

The Google Car could turn out to be a dangerous idea -- as "dangerous" as any of the ideas presented by the ex-gang members, neo-Nazis and Muslim extremists at the current Google Ideas conference. A consumer-ready Google Car could challenge our deepest-held notions of what the boundary between man and machine should be when robot drivers guided by satellites and computers begin to navigate the transportation grid.