There's chaos on the buses: Model reveals why shuttles come all at once or not at all.

There's chaos on the buses: Model reveals why shuttles come all at once or not at all.: "You wait half an hour for an airport shuttle bus, then two show up at once. It's not bad planning, it's chaos, says Japanese researcher Takashi Nagatani of Shizuoka University.

The unpredictability of shuttle-bus services may be inherent in the shuttling process, calculates Nagatani. He demonstrates that the average number of passengers aboard a bus and the distance between vehicles can fluctuate unpredictably, resulting in a less efficient system. Chaos emerges even in a very simple set up of two buses picking up regularly arriving passengers and taking them at constant speed to one destination."

It's not evil, it's chaos.