Alphabet (GOOG 0.56%) (GOOGL 0.69%) subsidiary Waymo is about to bring driverless cars to public roads for the first time -- by taking the driver out of some of its self-driving test vehicles.

Until now, all "self-driving" test vehicles on U.S. public roads (from all companies) have had human drivers at the wheel. Testing on public roads without a human driver at the ready is an important step toward building public acceptance of autonomous-vehicle technology.

But what does it mean for Waymo and its self-driving rivals?

A white Chrysler Pacifica Hybrid minivan with Waymo markings and visible self-driving sensors on a public road

For the first time, Waymo's self-driving test vehicles are operating without human drivers ready to take over. Image source: Alphabet.

What Waymo said: Truly driverless vehicles on public roads

The news involves Alphabet subsidiary Waymo, which is the company formerly known as the Google Self-Driving Cars Project. At a technology conference on Nov. 7, Waymo CEO John Krafcik announced that Waymo is now running test vehicles without a human driver in a designated area near Phoenix, Arizona.

That's groundbreaking news. Krafcik said that Waymo will soon break more ground: Over the next several weeks, it will invite members of the public to take trips in its fully self-driving vehicles.

The company elaborated on Krafcik's announcement in a post on its corporate blog:

After more than eight years of development, we're taking the next step toward unlocking the potential of fully self-driving technology. Starting now, Waymo's fully self-driving vehicles  --  our safest, most advanced vehicles on the road today -- are test-driving on public roads, without anyone in the driver's seat. To date, Waymo vehicles have been operating on public roads with a test driver at the wheel. Now, in an area of the Phoenix metro region, a subset of our fleet will operate in fully autonomous mode, with Waymo as the sole driver.

Waymo noted that its autonomous driving system has accumulated more than 3.5 million miles on U.S. public roads since its testing began back in 2009. On top of that, it's using test software that adds a simulated 10 million miles of testing every day.

Waymo also noted that all of its current test vehicles have the backup safety systems that most experts think are required for safe autonomous driving, including backup steering and braking systems that can bring the vehicle to a safe stop if needed.

Simply put, this is a big deal.

What Waymo will get out of this

Waymo likely has several goals here:

  • Giving the public first-hand experience with driverless vehicles, so as to build enthusiasm and ease concerns
  • Learning how consumers interact with driverless cars, how people expect them to behave, and how they'll be used
  • Signaling -- to rivals, potential partners, and potential Waymo employees -- that its technology has reached the point where it's ready for this step
  • Proving to regulators (in other jurisdictions) that this kind of testing is safe

All of those are important -- not just to Waymo, but to advancing self-driving technology generally.

Does this mean Waymo is now the undisputed self-driving leader?

Yes and no. We knew that Waymo's technology was, at the very least, near the front of the self-driving pack. But others are likely close behind, including General Motors, Delphi Automotive, and possibly Ford Motor Company and a few others.

The fact that Waymo has begun this testing tells us two things: First, Waymo feels that its technology is ready for such a test. Because Waymo has been careful in its testing so far, its decision to proceed here inspires confidence. Second, it tells us Waymo has secured legal permission to operate its vehicles without human drivers in a specific, defined area of Arizona.

Don't discount the value of that legal permission. If Waymo's testing goes without incident, lawmakers and regulators in other areas will almost certainly be more willing to allow similar tests by similarly prepared rivals.

Long story short: It may turn out that companies like GM have technology that's effectively on par with Waymo's. But Waymo was the first to get permission to use it, and if it goes without incident, Waymo's test may open the door for other truly driverless tests in other areas.