Waymo’s ride-hail app is now available in the Google Play Store for Android users, but don’t download it expecting to summon a self-driving car right away.

Waymo, the self-driving unit of Google parent Alphabet, officially launched its first commercial autonomous taxi service in the cities surrounding Phoenix late last year. But the app that riders use to summon one of Waymo’s self-driving minivans was only available via a private link in an emailed invitation. Now anyone can download the app and add their names to Waymo’s growing waitlist for riders — but depending where you live, you might be waiting a really long time.

a precursor to scaling up its commercial taxi service?

Adding the app to Google Play would appear to be a precursor to scaling up its commercial taxi service. It’s the company’s way of saying, “We’re ready to take on a much bigger ridership.” Waymo says that interested riders with Android devices can download the app and join the waitlist to ride. “Once accepted from our waitlist, you’ll be able to request rides in the app and take your first trip,” the company says.

Waymo is essentially opening the flood gates for a torrent of requests to ride in its self-driving cars, with the implication that soon enough everyone in the Phoenix area will get the chance.

To be clear, Waymo is only operating its commercial service in the Arizona cities of Chandler, Mesa, Tempe, and Gilbert. And its cars aren’t even available to the vast majority of people who live in those communities. To be approved as a rider, you must first be a member of Waymo’s early rider program. Those riders are required to sign nondisclosure agreements before they are allowed to take test rides in Waymo’s vehicles.

Eventually, those early riders can request to be moved over to what was previously known as Waymo One, but has now been rebranded as Waymo’s public service. (Both the early rider program and the public service now operate under the banner of Waymo One. The company is also working on trucking, delivery, and several other business ventures. Confused yet?)

A spokesperson for Waymo wouldn’t provide an update on the number of people it has using its vehicles right now, only confirming that the number is in the “hundreds.” Waymo isn’t encouraging people outside the Phoenix area to download the app, but if you’re feeling lucky, go for it.

What about iOS users? The app works in iOS, but Waymo says it will still be a while more before it debuts in the App Store.