Self-driving cars, (or autonomous cars, driverless cars or robotic cars), is a vehicle that is capable of sensing its environment and navigating without human input. Google has been out first with such cars back in 2012, but other companies like Tesla Motors is also working on autopilots as of 2015.
Already before 2012 Randall began making references to Self-driving cars (the word he has used most often, and never autonomous cars as is the Wikipedia article title), and since then it has become a recurring theme, with comic 1720: Horses being the one that sparked the creation of this category. But already in 1559: Driving these kind of cars where the main cause of the pun, and also in 1493: Meeting where they a big part. In other comics they have just been mentioned.
Here is a list of comics that relates to Self-driving cars: