Posts Tagged ‘gas is expensive like whoa’


opportunity cost, or, bus vs. car part two

November 4, 2011

I just wrote this in a comment response, but then it occurred to me that it’s a) supremely long, and b) somewhat useful.  Here’s some opportunity cost math about my commute.

One way, door-to-door in light traffic, driving takes 45 minutes, assuming I can find a parking spot that doesn’t require a permit across the street from my office (typically — but not always — a valid assumption). It also assumes that there’s no fiery accident on I-40, which is not a very good assumption really.

One way, door-to-door right now, the bus takes 1 hour, 20 minutes, assuming again I can find a parking spot without a permit at the park-and-ride (true if I arrive for the 7:40am bus) and that I walk the mile from the stop to my office. I am planning on parking a shitty bike (<$30) at the stop and using it to get back and forth, as soon as I have time to buy one. This should cut it to 1 hour, 5 minutes.

So, this week, taking the bus was 35 minutes longer one way. If I spent all of that time working for my miserably low-paid (but with benefits!) job, I would make $8.75, or an extra $17.50 a day. If I spent that time writing freelance science articles, I could make something ranging from $0 to about $40 every day. Clearly, the economics of driving win here.

But what all of this ignores is that on the bus, I actually do have about 35 minutes in which I could be doing useful work (assuming it’s not a wifi bus and I spent that time reading comics on the internet). On Wednesday, I used it productively in the morning, but the rest of the week I was just reading Malcolm Gladwell’s “What the Dog Saw” and learning about ketchup and creative genius and the guy who invented birth control (awesome read). Anyway, if I were motivated, I could easily make up the lost time by being useful, and after I get a bike, if I’m useful I’ll actually be gaining 15 minutes of productive time every day by riding the bus.

Another thing this opportunity cost calculation ignores is that I only depart my house at 7:15am if I’m taking the bus. If I’m driving, I use that extra 35 minutes to hit snooze three times because I forgot to reset my alarm clock from when I took the bus the day before. So it’s not even sleep that’s worth anything except the comfort of lingering half-awake in warm blankets.

But mostly, what all of this means for certain is that I need a job closer to home.  Sigh.


scary fact of the day

November 2, 2011

I used to complain about public transit being doubly cost ineffective.  The fees charged to riders didn’t do much to support the cost of running the buses, but the fees were still more expensive than the equivalent gasoline cost, assuming a rider had a car that has pretty standard fuel efficiency.

Guess what?  My commute is now cheaper if I take the bus, even if I were to pay full fare instead of using my employer-sponsored bus pass.

Here’s the math.  These calculations assume I paid $3.39/gallon in gas (the price I last paid at the pump), and that I was getting 31 mpg (my usual mileage in my ’96 Camry).

  • Driving, my commute is 30.9 miles each way.  That’s 2 x (30.9 miles x $3.39 per gallon ÷ 31 mpg), a total cost of $6.76 every day.
  • Using the park-and-ride, I drive 6.4 miles from my house to the bus station.  I walk or bike from the stop to my office.  That’s 2 x ($2.50 in bus fare + 6.4 miles x $3.39 per gallon ÷ 31 mpg), a total cost of $6.40 every day.
  • Because my employer pays for my bus pass, the park-and-ride’s actual cost to me is $1.40 every day.
  • Or, because I like working in differences, riding the bus saves me $5.36 every single day.  That’s $26.80 a week, or $107.20 every month.  Over the course of the six months this job lasts (ah, grant funded positions), riding the bus has the potential to save me almost $650.
  • Even if I carpooled with one other person (I drove every other day), and even if I assume I didn’t have to drive out of my way at all to do so, riding the bus would still be almost $3 cheaper per day.  Insanity.

Yay simple math.  I was inspired to take a break from reading lots of transportation statistics and cost-benefit fact sheets and run the numbers (my new job is doing some education and outreach for a clean transportation group, so I’m spending a lot of time familiarizing myself with our existing literature).  Perhaps I’ll be back later with the more complex emissions comparison, if I feel inspired.