I agree with you about it being exciting, but Waymo haven't actually ordered the minivans - the press release says up to 62,000 minivans, so the actual size of the order is not clear.
https://venturebeat.com/2018/05/31/waymo-orders-62000-fiat-c...
https://venturebeat.com/2018/05/31/waymo-orders-62000-fiat-c...