Bus Schedules and Probability

As any large city, Pittsburgh has a mass transit system. It's run by the Port Authority of Allegheny County (PAT for short). It's also the worst public transit system ever.

You wouldn't know it if you were to look at the display case of maps in the CMU University Union. There's dozens of blue bus schedules, and they only have the ones that CMU students might be interested in. The buses run along major pathways, and they appear to come very frequently. Notice the keyword "appear".

Let's say, for example, you were in Squirrel Hill, at Forbes and Wightman. You want to get to CMU. What time should you arrive at the bus stop? There are many options: 61A, 61B, 61C, 59U, 61D, 61F, 56U and 501. We'll not look at the last 4 since they aren't as frequent. You'll notice that the 61C (www.ridegold.com) comes every 5 minutes. When you add in the A, B, and 59U, you'll realize there should be a bus coming every 2 minutes. How totally awesome is that? I think I'll just go outside right now.

And you wait. In the snow. For 45 minutes.

While you wait, 8 buses go by in the OTHER direction.

(Did I mention that the walk to CMU is 30 minutes? But of course, by now, you won't leave, because you're due for a bus anytime now, right?)

Oh my God! A BUS! We're saved! Uh...wait...it's not stopping. Why? Cause it's full of passengers farther down the line who were ALSO waiting for a bus for 45 minutes, and they just can't squeeze any more in.

But not to worry. There's another 3-5 buses right after it. You see, the PAT buses get lonely out on the cold Pittsburgh streets. It's scary out there. So they pack up. Now, hopefully, you've run across a big pack, and you'll hop on the last one. If it's a small pack, well, then you're SOL. Better start walking.

It seems that every time one waits for a bus in Pittsburgh, at least 3 buses go by in the other direction. Even considering the packs, there are never enough buses coming by to account for the number that SHOULD be coming. The current theory is that Pittsburgh has several wormholes that cause the laws of probability to warp in unusual ways.

BTW, if anyone is thinking that the buses are late because they are "caught up downtown", this theory has been proven false. I once caught the very FIRST 61B of the morning. It was around 5:30 in the morning. The bus was coming from the East neighborhoods, it had only 3 people on it, and it was 10 minutes late. Besides that, SH to CMU is going towards downtown, not away from it. Of course, the buses in the other direction are always fine.

Lest you think this has something to do with traffic, let me assure you that, as a graduate student, I have frequently ridden the bus at very odd hours. The probability never works out in your favor. Wormholes.

There do appear to be certain pathways on which there are no wormholes. The 56U, for example. It only comes once an hour, and it only comes during the main commuting times. But you better not be even 1 minute late to the bus stop. When the schedule says 9:36, it means 9:36. We can therefore eliminate any wormholes on the 56U pathway.

I propose someone make this a research project. Please. Pittsburghers are freezing at the bus stops.