刚在纽约时报网站看到这篇文章。

我们在车站等巴士的时候，如果目的地只有两三站的距离，经常我们会想我们如果现在走过去，会不会比在这里等下一辆巴士更快? 但是往往我们走到一半的时候就看到巴士呼啸而过。等还是不等? 这个问题现在有人来提供答案了：我们或许应该呆在车站。

附文：

Bus-Wait Formula, The
By CLIVE THOMPSON

You arrive at the bus stop to catch the ride to work, but the bus isn’t there. Your destination isn’t very far, so you think, Hmm, maybe I should just walk. But then you might find yourself halfway between stops when the bus whips past, which would be deeply annoying. What to do? Should you walk or should you wait? 

This question has plagued commuters for years, but this year three undergraduate students at Harvard and Cal Tech decided to resolve it. “We were sick of sitting at a bus stop, not seeing the bus and torturing ourselves over whether we should start walking,” says Scott Kominers, a Harvard student studying math, economics and ethnomusicology. So Kominers and his co-authors, Justin Chen and Robert Sinnott, drew up the problem as a classic game-theory dilemma, began crunching the numbers and, three pages later, had their answer: You should probably wait — and whatever you do, don’t second-guess yourself.

Buses, after all, are usually punctual and move much faster than you. If you start walking and catch the bus halfway through your journey, you might consider yourself fortunate — but even then you won’t have gotten to your destination any faster. What’s more, Kominers — like a good economist — points out that waiting allows you to “optimize” your time, because you could get some work done while hanging out at the bus stop. There’s also a practical problem with walking, because people who decide to walk usually pause at each stop to see if a bus is coming, which drags their journey out. “You think you’re not slowing down if you stop, but you’re adding a bunch of time each time,” Kominers adds.

Mind you, their equation breaks down in extreme cases. If your journey is relatively short — less than a mile — and you suspect the next bus is half an hour away, they calculate that you should walk. (Though you should walk decisively, without dallying at each stop along the way.) But since most trips involve more-punctual buses and longer journeys, waiting is, far more frequently, the winning strategy. Or as Kominers concludes with some delight, “Laziness almost always works."