Waze, the navigation app owned by Google, announced today that the carpooling service it launched last year is now available in the nine counties that comprise the Bay Area, as well as Sacramento and Monterey. That means that a growing number of Californians can use Waze, an app with 75 million active users, to locate strangers to fill the empty seats in their cars on their way to work.

To be sure, what Waze is offering differs greatly from Uber and Lyft’s respective carpooling services. Drivers are paired with riders with nearly identical commutes based on home and work addresses. Waze Carpool riders are charged a maximum rate of 54 cents per mile, the current IRS reimbursement rate for business travel by car. And drivers and riders are limited to two rides a day. This is not a money making service, but rather an attempt by Google to test the waters in the growing ride-sharing market.

Where this gets super interesting is when you start to think about Google’s ongoing work on self-driving cars and all that could mean for the future of transportation. Could Google combine Waze with its autonomous vehicle spinoff Waymo to launch a self-driving carpool service to compete with Uber? The patents that Google has been filing seem to suggest as much. If Waze's carpooling service is successful and expands to other cities, it's not difficult to see Google using it as a platform on which to launch a fully commercialized, on-demand driverless car service. With no drivers to pay commission, any micro-fare paid by riders goes straight to Google.

Or it could sputter and fail miserably because who uses Waze to arrange taxi rides? It took Uber almost six years of nasty, debilitating fights with taxi owners and city governments to get where it is today. And there’s no reason to assume Google can just waltz into this space, start offering a carpooling service, and successfully knock Uber off its perch.

But let’s not get ahead of ourselves. In addition to expanding its service boundaries, Waze also announced a partnership with three major Bay Area organizations — the Metropolitan Transportation Commission, the University of California-San Francisco, and Kaiser Permanente — to minimize parking and traffic congestion. Those organizations will encourage their respective employees to use Waze to carpool to and from work.

Still, the process of arranging a ride isn't easy: it takes two different apps. Select employees interested in hitching a ride through Waze can use the new rider app to find a driver. Meanwhile, drivers use the regular Waze app to find riders.

Carpooling may be all the rage among tech companies, but its far from a sure bet. UberPool and Lyft Line are continuing to grow into new cities, but Lyft’s experiment with “casual carpooling” in San Francisco ended abruptly after the ride-hail company failed to find enough drivers willing to invite strangers into their cars. Professional Uber and Lyft drivers tend to hate carpooling, as it generally forces them to do more work for less money. And while carpooling is touted as a more environmentally friendly alternative to normal ride-hailing or ride-sharing, it certainly can’t beat the greenest way to travel: good old public transportation.