Horses
Horses
[Ponytail walks right with Cueball.] Ponytail: Drunk driving was less of a problem before cars. If you got on your horse drunk and fell asleep, it could just walk home.
[Zoom in on Ponytail's torso; she holds up a palm to proffer an idea.] Ponytail: And if you tried to ride into a tree, the horse could be like "No." Ponytail: Forget human drivers – that's the benchmark we should be judging self-driving cars against.
[The front end of a car, with the bottom of the windshield and the right side mirror just inside the panel is parked before White Hat. He is holding his hand, palm up, out to the left towards the car as he brags about it to Megan and Cueball standing in front of him admiring the car. At the top left of the panel a small frame with a caption is placed over the panels frame:] Soon: White Hat: This baby has 200 horses under the hood and 3.5 in the computer. Megan and Cueball: Ooooh!

The programming of self-driving cars has been in the news lately, as engineers and philosophers debate what rules the cars should follow in dangerous situations (for instance, what to do when forced to choose between hitting a pedestrian or swerving into oncoming traffic). Ponytail suggests one approach for solving this problem: to think of the car as behaving like a horse, using its own intelligence and ignoring dangerous commands in the interests of self-preservation.
The comic begins with Ponytail claiming that in the old days, riding a horse or driving a horse drawn vehicle while drunk was less dangerous than drunk driving today. Given the higher speed and the denser traffic today this might seem plausible. On the other hand, modern cars have seat belts, airbags, and other features designed to save lives when crashes do occur; horses and horse-drawn vehicles lacked these safety features. However, if you do fall asleep on a horse, it will not suddenly walk into a tree or other obstacle, and it may actually just stop walking while you sleep.
Ponytail expands the argument by stating the horse itself will be acting in the interest of its own self-preservation. She finally states that in a comparison of the ability of self-driving cars, we should forget humans, and instead it should be the ability of horses that should be the benchmark that the self-driving cars should be judged against.
This segues into a scene in the near future where White Hat is bragging to Cueball and Megan about the features of a car (in order to sell the car to them) by comparing the features to those of horses. Car engines are traditionally measured in horsepower , which (roughly) compares the power output of the engine to that of a horse. White Hat goes a step further, claiming that the car (which is presumably self-driving) has an onboard computer with driving abilities equivalent to 3.5 horses, comparing the car's ability to mitigate for a drunk driver and/or avoid obstacles to that of a horse. White Hat has been depicted as a salesman before in 1350: Lorenz and similarly earlier in 260: The Glass Necklace .
The title text features more comparisons of the car to horses. In the text, Randall states that the car has 240% of a horse's decision-making ability and produces only 30% as much poop as a horse. This statement is absurd because it claims that the self-driving car will be producing poop. It also suggests that even with 3.5 times as much horse-intelligence as a horse, the car may only have 2.4 times the decision-making ability, although the car in the title text could also just be a different car from the one in the comic.
Note that riding a horse while drunk is in fact still dangerous and illegal in many places (for example, the UK and Ireland ). A badly-driven horse can throw off its owner, trample passersby, fall on bad surfaces, and destroy any wagon or carriage it's pulling. A self-driving car should be able to understand road rules, which a horse will not - which is presumably why the cars in the comic and the title text are both specified as being more intelligent than a horse.
In 887: Future Timeline dogs driving cars are mentioned. Self-driving cars is a recurring topic on xkcd. In 1461: Payloads spacecraft mass is measured in horses.
[Ponytail walks right with Cueball.] Ponytail: Drunk driving was less of a problem before cars. If you got on your horse drunk and fell asleep, it could just walk home.
[Zoom in on Ponytail's torso; she holds up a palm to proffer an idea.] Ponytail: And if you tried to ride into a tree, the horse could be like "No." Ponytail: Forget human drivers – that's the benchmark we should be judging self-driving cars against.
[The front end of a car, with the bottom of the windshield and the right side mirror just inside the panel is parked before White Hat. He is holding his hand, palm up, out to the left towards the car as he brags about it to Megan and Cueball standing in front of him admiring the car. At the top left of the panel a small frame with a caption is placed over the panels frame:] Soon: White Hat: This baby has 200 horses under the hood and 3.5 in the computer. Megan and Cueball: Ooooh!
