Friday, August 28, 2020

New Bus Route, Who Dis?

Anyone know the schedule for this bus route? How often it runs, the route map, etc.?


[Pictured is the bus shelter at the Central Campus Transit Center, the hub for the university’s campus-focused (vs. Michigan medicine-focused) buses. During normal operation, the electronic signs display the arrival times for incoming routes (e.g. “Bursley-Baits 4 min,” “Commuter North 9 min,” and so on). However, on weekends when few routes are running, they sometimes display a message along the lines of “No route information available. Sorry for the inconvenience.” For whatever reason, they dispatch this information split up as “No route information available/Sorry for the/inconvenience.” There’s room on the sign to display the whole message at once – look at the sign behind it with hiring information – but no, they wish to broadcast INCONVENIENCE 1/3 of the time.

Photo taken last spring, but I think it would be a pretty good route to represent 2020. Instead of showing up when you need it, like the Knight Bus in Harry Potter, the Inconvenience Bus is always running extremely late or pulls away from the stop early as you’re running to catch it, takes scenic detours at least 50% of the time, breaks down if you’re on your way to important meetings, and keeps disappearing from tracking apps, then reappearing either at the stop past yours or in Siberia. Wait, this sounds like public transportation as it already is under normal circumstances . . . just kidding. Mostly.

For real though, both the university and the Ann Arbor Area Transportation Authority (AAATA) are planning to reconfigure their routes this fall to prioritize common destinations and reduce the number of people on buses/time spent on the bus. This does mean that instead of one 25-minute bus ride you might have two 10-minute bus rides, plus time spent waiting to transfer, but depending on how the probability of virus transmission varies with time, it might actually be better to be in contact with more people (two separate bus rides) for less time. For example, assume the probability you get infected is directly proportional to time spent on the bus with an infected person (say 1% for every five minutes) and there’s a 1% chance someone on the bus is infected. If we compare one 30-minute ride to two 15-minute rides, the chance you get infected on the 30-minute ride is 0.01*(6*0.01) = 0.06%. Conversely, the chance you don’t get infected is 99.94%. For one 15-minute ride, you get infected with a probability of 0.03% and stay healthy 99.97% of the time, so for two 15-minute rides, the chance you don’t get infected is (0.9997)2 = 0.99940009 or 99.940009%, a (very) slightly higher chance of not being infected by taking two shorter bus rides vs. one longer ride.1 I have no idea if infection is directly proportional to time, and this also assumes random distribution of infectious people and that total time on the bus is the same, but it’s at least possible that the university isn’t doing some sort of smoke and mirrors/song and dance thing to make people think they’re making these plans to keep people safer.

Of course, this could all still be a CYA move by the university since the route reconfiguration is to make all the routes 15 minutes or less, and part of the CDC’s definition of “close contact” for contact tracing is spending more than 15 minutes near to an infected person, so now U-M technically never has to contact trace anyone from the buses. File this one as more probable than 5G causing coronavirus but less likely than the Earth is round.

1The funny part about this analysis is that the “safest” thing to do is split the bus ride up into an infinite number of infinitely short rides. Which isn’t the most physically possible solution, so maybe now we need some optimization of “coronavirus risk” vs. “# of times students will willingly transfer buses before mutinying.” My guess is two buses before revolt, because bus transfers are a pain in the neck.]

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