Thursday, January 24, 2008

A commuter asks, “So, do I wait, or do I walk?”

As a Londoner and a non-driver, the much vexed question, “ How long do I wait for the bus?” is one that occupies much of my commuting time (far too much, for those of you who are interested). Once you start waiting, you feel obliged to wait just those extra five minutes, in the almost certain knowledge that, if you don’t, the bus will arrive just as you reach the point of no return.

It was, therefore, with a degree of fascination that I read news of research by Scott Kominers, a mathematician at Harvard University, indicating that, in the absence of information, the lazy option is, statistically, the best one.

I live in the north-west London suburb of Kingsbury, sufficiently far from a useful Underground station to make using a bus a viable option. However, I have a choice of two buses, one of which runs more frequently, but takes longer to get to Wembley Park station, the other less frequent, but runs me to Kingsbury station in a shorter time. Kingsbury adds four minutes to my train journey but I get a seat. Dilemmas, dilemmas…

My bus stop has something called ‘Countdown’ which, technically, tells me how long it will be before the next bus comes. The catch is, it isn’t wholly reliable. It might, for example, tell me that there is a bus due in eight minutes, when one is actually coming around the corner. On the other hand, it might tell me that there is a bus three minutes away, which remains agonising that close for another five minutes. Alternatively, it mysteriously disappears into the West Hendon triangle, never to be seen again.

What I really need is a mathematician to tell me what my best option is. Actually, what I really need is a helicopter…

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