xkcd.WTF!?

Explanation ➲

This comic demonstrates one reason why vehicles have gotten progressively larger and more powerful, due to a type of arms race between drivers. When vehicles of different sizes share the road, passengers in the smaller ones will usually be more at risk in collisions, since the body construction and lower inertia generally provide less protection. So, for safety reasons, people have an incentive to buy larger cars. According to the comic, this causes a cycle of cars for increasingly selfish owners, which reaches a point of absurdity due to the cost and mass of giant cars, implying a never-ending vicious cycle.

In the "Soon" panel, Randall has extrapolated this to adding spiked armor and weaponry to large cars, and other drivers will need to outdo this to compete on the road. This scenario is reminiscent of the vehicles from the Mad Max franchise, and of the Slag Brothers from Wacky Races. Unfortunately, the whirling spike club scenario is problematic (not just in terms of injury or death but even in the happy path): if all the cars on the road have whirling spike clubs, as soon as your car comes in contact, your club will be destroyed or at least damaged. This will make you prey for the cars who have not yet been in an accident.

The title text views this from the opposite perspective. The owner of a large car is worried that they'll kill people in small cars, so believes that small car drivers shouldn't drive on the road at all and should be restricted to the sidewalk for their own safety. Driving the smallest cars in pedestrian spaces is obviously absurd, but follows the prior trend of separating bikes from car traffic 'for cyclists' safety' and often having them share pedestrian spaces due to 'practical' constraints. While this reduces conflicts between cyclists and drivers of motor vehicles, it results in cyclists and pedestrians becoming an inconvenience and danger to each other instead. In the car-centric view, it is not worth creating separate infrastructure for bicycles and similar small vehicles, so the title text's extension of the trend is to classify small cars as bike-like vehicles, even though this endangers both smaller vehicles and pedestrians.

Biking on sidewalks is illegal in some jurisdictions, with a greater number banning small powered vehicles like e-bikes. Where either kind of bike is allowed, laws generally require that the rider take precautions like riding at reasonable speeds when near pedestrians, alerting pedestrians when passing, and yielding to pedestrians when needed. Small, low-speed carts do routinely share some larger pedestrian spaces, such as golf courses and large airports, but even these would have trouble safely passing on regular sidewalks. Smaller single-occupant electric vehicles (mobility scooters) frequently share pedestrian spaces, but their limited speeds reduce the frequency and potential severity of impacts.