The goal of this project is to explore the most cost effect speed to commute from one town to the next. I currently live in Hammond, LA (and usually commute by bike). There are many people in this area that go to Southeastern Louisiana University and commute from New Orleans, Baton Rouge, Covington and Slidel. These commutes are most on interstate highways at a near constant speed.
Skip all the cool stuff and go straight to the calculator
Key Ideas
There are two factors that apply here. First, the faster you drive, the lower your gas mileage. I think everyone can readily accept this idea, but here is some data from the 2001 Transportation Energy Data book.
Calculating fuel economy as a function of speed is simple in theory, but difficult in practice. The difficult part is determining the different coefficients of "drag". Needless to say, for this study, I will use an approximation from the above data. From this data comes the recommendation that you lose 8% efficiency for every 5 mph over 60 mph. From the above graph one can see this is approximately true. Enough of that, I will discuss it more in the fuel efficiency section.
The second idea is that the slower you drive, the more time you waste (time that could be used working and making money).
Input Data
I am going to make an applet. You need to enter the following:
- the distance you commute (one way)
- the efficiency (gas mileage) of your car at 60 mph - or any other specified speed above 60
- how much you make an hour (for salaried positions, I will just calculate your rate assuming a 40 hour work week - yes, I know this is not accurate)
- the price of gasoline in your area.
From this, the applet will calculate the speed that costs you the least amount of money
About this thing
I am not sure what to call this, I guess it is an article. Anyway, I am writing this as I work on it. This is different from my usual manner. Normally, I do all the work and then write it. For instance, as I write this now I have no idea how things will turn out.