## October 5, 2019

### Modeling my Commute

When I was deciding if I wanted to work at the Center for Mathematics Achievement the only drawback was the commute. It's a mere 15 miles as the crow flies from home to the office so it shouldn't be that bad, right? Nope. To get there at 10:30 am on a weekday google tells me it could take anywhere from 45 minutes to an hour and a half to drive! An arrival time between 8 and 9:30 could easily take 2 hours. Those numbers are awful, and I'm committed to not being the traffic (https://twitter.com/Dale_Bracewell/status/1176980860525895680) so I started researching public transportation options. This is where the fun started, because I'm really lucky to have lots of options.

• I could walk to the bus
• I could drive to the commuter rail
• I could drive (farther) to the subway

Each of these has advantages and disadvantages - total time, cost, schedule flexibility. So I started with the cheapest option (no parking and bus/subway) and worked my way down to the option I thought I'd dislike the most (I really don't like driving).
The research was somewhat challenging in terms of identifying all my options, but once I thought of an option it was easy to look up schedules and costs. Then I had to dig deeper, at which point I learned some compounding factors - like the train station closest to my house has really limited parking. But at this point I still had 3 viable options, the 3 bullets I started with. The cheapest option takes the longest. The next cheapest option requires lots of driving. The most expensive option requires little driving, an easy transfer - the trains are all in the same building, and I get to sit on the train where I'd be stuck standing on the rush hour subway.

At this point I was really wishing I could do some calculating - but I didn't have a way to calculate this. What multiplier do I give for driving (yuck) vs. subway (meh) vs. train (yay)? No one wrote this problem for me so I don't know if Tina dislikes driving twice as much or three times as much or ten times as much as the train. One of the things I really like about the high school curriculum from IM is that we wrote modeling prompts exactly like this. There are scaffolded versions where we provide the data or guiding questions, but there are also wide open versions like Tina needs to get from Salem to Cambridge, what should she do? It's realistically challenging.

So what did I do? The first day I drove to the Lynn train station. First I learned that while driving south seems logical because I'm trying to go south, so is everyone else so I was sitting in traffic and trying to make a tricky left turn across traffic. Then I learned that it's an amazing \$2 a day to park there. And finally I learned the trains don't run exactly at the times they say so my train to train transfer was really tight. On the way home I tried subway to train and the subway was just as crowded as I'd worried it would be. The next day I drove north to the Salem train station. There was no traffic because I could leave after both schools on my route started and I was going in the opposite direction of the rest of the traffic. It costs more both to park and to ride the train from Salem, but there's an express train which gets me there with a cushion to make my train transfer. So for the month of October I'm committing to this plan because it's the one that ranks highest for personal happiness during the commute. At the end of the month I will see if my bank account happiness and my personal happiness balance out. This program Lesley University offers should help with my bank account happiness:
My personal happiness at work has definitely been high enough to outweigh the pain of a long commute. I'll be sure to tell you all about what I'm doing at work soon, but for now you should read this newsletter because I wrote it and it tells you some of what we're up to!

#### 1 comment:

1. Google maps tends to be good about computing transit times, though perhaps not so good at mixed park-and-ride options.