My thought at the time was that the audience would relate to food calories and that would simplify things.

Reading your post now, I see that I could have said food Calories and made more people happy ;-)

so a gallon of gasoline has 31,000,000 calories

and 31,000 Calories

Dropped in quite accidentally, while searching for information on biodiesel yields!! Yet liked the discussion in the blog article…let me take time to “drink” your argument – oil is oil whether used as food or as diesel….hmmm

Thoughts from http://www.castoroil.in

As far as which to compare with which, I think it’s all just numeric play. As I ride my bike I mentally compare with the people I see in a larve SUV (one person, no observable cargo, on a beautiful road not ‘requiring’ a truck).

I left out the whole speed thing because I was thinking, in the speed domain a bicycle can easily achieve, how does a car compare? I kind of left it that machines can certainly more energy faster than a human on a bicycle ever could. I’m sure a dragster burns more in 5 sec than a bicyclist all day. And so on.

Best wishes.

Note that figures for human-powered transportation are in incremental consumption above the resting level.

Road bicycle plus rider
4mph 8.4 kcal/km 2440mpg
10mph 15.6 kcal/km 1310mpg
15mph 24.4 kcal/km 840mpg

Auto plus one rider
30mph 539kcal/km 38mpg
60mph 820kcal/km 25mpg

That calculator doesn’t seem to work very well. It determines that it takes more energy to travel on a bike at 5mph than at 18mph, but the wind resistance drag increases with the square of the speed, and wind resistance is the limiting force for cyclists on a flat road. You might ask them for their calculations so you can make better ones. Bicycling Science goes through the studies and calculations it uses to get to those results. Worth a read.

A more important point, which isn’t really a quibble with your result, is that if the purpose of a car is to one or more people, what is the point of comparing the mass moved? Put another way, your figures demonstrate that we can move one person 32 miles with 1440 calories by bike or the same person 32 miles with 30800 calories (or more than 21 times as much) by car.

To be complete, you should compare a 1/5 loaded passenger train WRT kcal/passenger/mile. Bicycling Science lists the loaded train as 183mpg @ 30mph and the 5 passenger car as 170mpg @ 30mph.

Bicycle 190 – 30 = 160 * 684 miles per gallon = 109,440 cargo pound miles.
VW Jetta Diesel 4,302 – 3,197 = 1,105 * 30 mpg = 33,150 cpm.
Semi 80,000 – 32,000 = 50,000 * 7 mpg = 350,000 cpm.

http://www.exrx.net/Calculators/CalRequire.html

We don’t know of course, but I assume the bikemetro calories are the increase over normal, non-strenuous activities like driving.