While a minivan may not be the self-driving vehicle of your dreams, Google said in May that it "gives us an opportunity to test a larger vehicle that could be easier for passengers to enter and exit, particularly with features like hands-free sliding doors." Judging by the photos, it has also developed a roof-mounted sensor pack, including radar, lidar and cameras that protrudes less, and some kind of bumper-mounted device.

While a minivan may not be the self-driving vehicle of your dreams, Google said in May that it "gives us an opportunity to test a larger vehicle that could be easier for passengers to enter and exit, particularly with features like hands-free sliding doors."

Google also said that the Pacifica design makes it "easy for us to install our self-driving systems, including the computers that hold our self-driving software, and the sensors that enable our software to see what's on the road around the vehicle." The model they chose is also a rechargeable hybrid minivan with a 16 kWh battery and 30 miles of range, providing the "robust" electrical system Google needs for its tech.

Mountain View kicked off the self-driving vehicle craze after it developed some of the first models after recruiting researchers that won a DARPA challenge in 2010. However, despite recently hitting the two million milestone, it's lagging considerably behind Tesla, which has logged over 200 million "autopilot" miles. 100 new vehicles means it has tripled its fleet size, so it's now aiming to "make transportation more accessible for millions of people﻿" with its autonomous technology, it said.