I’m been wanting to calculate this out before. Call it Brad’s myth of driving fast – debunked. Driving fast doesn’t get me places faster. There’s a lot of numbers in this one, it’s just my math background talking. I just want to caution you so I don’t give you a headache.

My commute from Amy’s:

to the bus stop exit is 29.5 miles

to work is 43.4 Miles

This morning I drove **only** the speed limit. To the bus stop exit took 32 minutes and to work took 47 minutes. So taking the minutes divided by 60, I get they took 0.533333 and 0.783333 hours respectively. Then dividing those figures by the miles I get my average MPH speeds (55.31 MPH and 55.40 MPH).

Now let’s assume that I got 10 MPH over the speed limit. I add 10 to my average MPHers from this morning. Now they are 65.31 instead of 55.31 and 65.40 instead of 55.40. The miles don’t change obviously. To figure out how long it will take, I take the miles divided by the speeds and then the total multiplied by 60 to get the minutes. So:

( 29.5 Miles / 65.31 MPH ) X 60 = 27.10 minutes

( 43.4 Miles / 65.40 MPH ) X 60 = 39.81 minutes

So if I’m driving 10 miles per hour over the speed limit, I’m not saving much time.

Amy’s place to the bus stop exit is only 5 minutes quicker if I’m going 10 MPH over the speed limit. Amy’s place to work only 7 minutes quicker if I’m going 10 MPH over the speed limit. So not worth it in my opinion.

Let’s look at the gas usage when driving slow or fast. I’m driving my 2005 Toyota Camry, which gets roughly 33 miles per gallon. According to Yahoo Answers, driving 75 miles per hour instead of 55 miles per hour increases fuel consumption by 20%, so we’ll assume only going 10 MPH over increases the fuel consumption by 10 percent. So in my Camry, driving ten over drops my miles per gallon from 33 down to 29.7 MPG. We get the number of gallons used for each trip by taking the miles of the trip divided by the miles per gallon. So:

**To bus stop exit (at speed limit):** 29.5 miles / 33 MPG = 0.89394 gallons

**To bus stop exit (10 MPH over limit):** 29.5 miles / 29.7 MPG = 0.99327 gallons

**To work (at speed limit):** 43.4 miles / 33 MPG = 1.31515 gallons

**To work (10 MPH over limit):** 43.4 miles / 29.7 MPG = 1.46128 gallons

So driving 10 MPH over the speed limit, it uses 0.0993 and 0.1461 gallons respectively. Doesn’t sound like too much. Multiplying that by $3 per gallon and then by 2 (for round trips), that only $0.60 and $0.88 cents per trip. Nothing there. Based on a 20 day work month, that’s only $11.92 and $17.54 to drive faster. Not too much, but if you are someone hurting for money that could help out by driving slower.

I also calculated all this on going from Amy’s to my Dad’s place (179.82 miles) and to my favorite park – Yellowstone National Park (1,009.63 miles). Driving 10 MPH over to my Dad’s house only gets me there 19 minutes early and ends up only costing me $1.82 round-trip. Out to Yellowstone, driving 10 MPH gets me there 108 minutes earier. Slightly less than two hours, which isn’t much on such a long trip. The gas it costs me round-trip if only $20.40 so on such a trip twenty dollars isn’t much.

I’d love to say that me driving all the way to work instead of taking the bus only costs me and extra $0.28 per day, but unfortunately I work downtown. So instead of $0.28 per day it becomes $10.28 per day extra because of the bad parking rates. Much too much to drive to work if I don’t have to. That and it sure is nice to avoid the traffic.

Anyone see if I calculated something wrong?

So what I can tell, driving fast doesn’t get you places that much faster, but it doesn’t cost you that much more. Of course this counts that all other facts are being equal. Maybe driving faster means you’ll be past a certain intersection before a major accident happens. Then again maybe driving that fast makes you much more likely to be the one that caused that accident. Hard to say, because those are uncontrollable factors. That being said, I’m going to try driving slower. Might as well enjoy my drive, knowing that if I rushed I wouldn’t get there much faster.

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