Biking vs Driving
Not too long ago, a coworker was talking about biking to work, and how much that saved in gas. It occurred to me that there is still energy used to ride a bike, but instead of gas, it’s food. There must be a way to correlate the energy use between these two methods of transportation.
Energy
It turns out that gasoline is a great fuel because it has an enormous mount of energy in it. While a Big Mac has about 1500 calories, a gallon of gasoline has about 31,500 calories of energy. There are roughly 6 Big Macs per gallon, so a gallon of Big Macs would have about 9,000 calories.
Efficiency
Riding a bike burns about 700 calories an hour at 12 MPH, or 60 calories per mile. A car, at 25 MPG requires 1260 calories to move one mile. So one gallon of gas has the energy required for a person to ride a bicycle for about 525 miles.
One gallon of Big Macs would allow a bicyclist to ride for about 150 miles
The Big Mac fueled, human powered bicycle is certainly more efficient.
Cost
But what if you look at the comparison in terms of the cost of fuel? Fast food is cheap calories, so, again using the Big Mac vs gasoline comparison, a Big Mac costs about $3, and has 1500 calories. That’s $0.002 per calorie. Pretty cheap, but at $4 a gallon, gasoline has 31,500 calories of energy, resulting in a cost of only $0.00013 per calorie.
One Gallon of Big Macs would cost about $18. $4 for a gallon of gas doesn’t seem too bad in comparison.
Chalk one up for gasoline.
Conclusion
Bicycles are much more efficient, but food has a lot less energy in it than gasoline. Add to that the fact that gasoline is cheap compared to food, you find that the cost per mile works out remarkably close. The average biker above would spend $0.12 per mile in Big Macs. The average car will burn $0.16 worth of gasoline per mile. So in the end, it turns out that while the numbers seem extremely skewed, it actually works out remarkably similarly.
So is it significantly cheaper to ride a bike than to drive? Nope, but, in my comparison, it is cheaper. But which is worse for the planet, drilling for oil, or raising cows and wheat and tomatoes, and lettuce, etc to make a Big Mac? That’s a little tougher.
To further complicate things, I drive a smart fortwo everyday and average 40 MPG. I need premium gas, so let’s assume I pay $4.20 per gallon. At that cost, I pay $0.105 per mile in fuel. That’s cheaper than a Big Mac fueled bicyclist. Of course, most bicyclists don’t eat Big Macs, they eat Clif Bars and such. But at $3 for 250 calories, a Clif Bar fueled bicyclist pays $0.72 a mile, 4.5 times the average car driver.
By the way, one gallon of Clif Bars would cost about $60, and have about 5000 calories.
Please feel free to check my math and verify my assumptions.
Assumptions:
“Calories” listed are actually “Kilocalories” to be consistent with food measures
Gasoline energy content: 125,000 BTU per gallon or 31,500 kilocalories per gallon
Gasoline cost: $4 per gallon
Big Mac energy content: 1500 kilocalories
Big Mac cost: $3
Average car fuel economy: 25 MPG at roughly 50MPH in the EPA highway cycle
Average bike energy consumption: 700 calories per hour at 12 MPH or 60 calories per mile


