We reported just last week that by adding 300 Chevy Bolt EV to its self-driving test fleet, GM was on its way to having the biggest captive self-driving test fleet in the world, but Waymo just crushed that dream today.

Waymo, formerly Google’s self-driving effort and now an official Alphabet company, announced that it is deploying 500 self-driving Chrysler Pacifica hybrid minivans in Phoenix. Interestingly, it’s not only about gathering data from driving since they will also give actual rides to the public through a new program.

John Krafcik, CEO of Waymo, explained the trial:

“Over the course of this trial, we’ll be accepting hundreds of people with diverse backgrounds and transportation needs who want to ride in and give feedback about Waymo’s self-driving cars. Rather than offering people one or two rides, the goal of this program is to give participants access to our fleet every day, at any time, to go anywhere within an area that’s about twice the size of San Francisco.”

Applications are open on their website.

Of course, like with any other self-driving program, they still have engineers behind the wheel to monitor and take over control in case of a disengagement.

They say that they have already been testing the program with one family over the last month and they released a quick video about it:

The 500 minivans are adding to the existing 100 that Waymo outfitted with its self-driving sensors already – bringing the total to 600 and making it the largest captive self-driving test fleet. Only Tesla with its open fleet of vehicles in customers’ hands can potentially gather more data, but as far as captive fleets, Waymo is now the clear leader.

More vehicles result in more data, which in turn accelerate the program and its potential commercialization. Considering that we are talking about a 6-fold increase here, we could see a significant step forward by Waymo with the data gathered from this new fleet.

The announcement also coincides with the start of deliveries for the plug-in hybrid version of Chrysler’s new Pacifica minivan, which has been favored by Waymo’s program. After several delays, Chrysler confirmed last week that they are finally being delivered to customers.