If you're going to compare the entire cost of walking to just the BTUs of the mpg of driving, you've got another thing coming.

First up, the users of that vehicle are still burning calories while driving. And their average speed for a short trip must include time spent at stoplights and parking - time must be calculated door to door. It's also unrealistic to compare, say, a five minute drive to a fifteen minute walk - while the pedestrian might be living a little longer, at least nine of those ten minutes are calories they don't burn for the rest of their life.

Second, the oil necessary to build the car and to build and maintain the roads it's on account for much more than we seem to be considering.

Third, that pedestrian is a lot more likely to be buying organic or local - throwing quite the monkey wrench in that walking average.

There I was feeling good despite not biking (see above) and now you tell me walking is no alternative?! Fortunately as a near-vegan I don't eat a typical SAD--Standard American Diet.

So I'll keep on walking, thanks.

There has got to be a term for this kind of crazy, counter-intuitive, utterly depressing analysis.  Until the Term Itself be revealed to us, by someone far cleverer than I, here is a stop-gap: Engineers With Too Much Time On Their Hands.  Acronym: EWTMTOTH.  Pronounced: Yoot m'toth.  Rhymes with "Goth."  Or else "broth" or "froth" or "moth."  Or even, if you insist, with "both," though I would not recommend it.  (I do not know how to pronounce "loth"; no matter, it is archaic and poetic, so one only has to figure it out on a page in a book.  But I am aware that J.R.R.Tolkien would be very disappointed.  He would want me to pronounce "Lothlorien," for example, just as he intended, and as he thought would come naturally to the English speaker.)

    The comparison also misses energy spent on increased medical costs due to obesity and lack of exercise (for drivers much higher than for regular walkers).

    There is also the matter of particle pollution from rubber tires and from brakes.

    And the increased asthma and other breathing diseases (all of which require energy to treat).

    The energy required to raise food generally contributes less to global warming than that required to move a car.

    This kind of statistical analysis is akin to comparing apples and watermelons.  It gives science a bad name.  Shame.

patrick

Do these meatheads want us to stop eating, stop driving, or stop walking?

Stuff a porkchop in it Limbaugh fans.

Last time I checked the vast majority of us exersize and healthy food addicts don't want anything to do with fossil fueled, chem food.

http://amazngdrx.blogharbor.com/blog

For fear of being branded an EWTMTOTH (I am a busy physicist, thanks), I must point out that when we're comparing "efficiency", surely what we want to compare is not the rate at which calories are burned, energy used per unit time, but rather the energy expended to travel a certain distance, or energy used per unit distance traveled. In other words: When I walk to the grocery store, am I burning more or fewer calories than if I bike there?

With the numbers given by plantface, this would mean that, biking at 5.5 mph, the woman would burn (36 cal/10 min)/(5.5 mi/60 min)=39 cal/mi. She would burn 77 cal/mi walking 3.5 mph.

Leaving aside the question of who exactly bikes as slow as 5.5 mph or walks as fast as 3.5 mph, it seems that by distance, biking burns fewer calories. I don't know if this makes sense: the wheels allow you to coast where your tired feet would have no choice but to plod along, but on uphills, you have to raise not only you but also your bike up the hill. I'd have to see more documentation.

Don't forget all the energy used hauling the raw materials for the car out of the ground, shipping them, producing the parts in the various factories, shipping the parts to the factory in which the car is assembled, and then shipping the car to the consumer...

Also, I don't know any environmentalist who promotes big-agra farming... Most of us want to improve the efficiency of transportation AND food production/distribution.

    Mihan, it takes longer to walk the same distance than to bike it.  So, biking should burn less calories.  If you biked the same amount of time as you walk, you will cover much more distance, and you will burn much more calories.

    Bikes are supposed to be efficient!!!

    The energy saved can be applied to other things.

    RedJenny, the idea that driving is more efficient than trains or buses is silly (I can't reach the page), you should note that one of the reasons Wikipedia can't be trusted is just because of this.  Someone has gotten in to it, and manipulated it.  Try not to use it as a serious source of information.

    Walk if you have time, bike if you don't.  Both are good for you and the environment.  It is useful to walk sometimes even if you bike a lot (different muscles).  

patrick

What about women who walk? Perhaps only women who weigh below a certain amount should be encouraged to walk.

Or perhaps we should say only humans who fuel themselves using low petrol-based diets should walk instead of drive.

Someone could come up with a calculator that takes into account all conditions, including food fuel as well as weather conditions, i.e. a stiff wind requiring more calories, walking in the cold vs walking in mild weather, etc. This would allow environmentally correct decisions to be made in every instance.

Is there a grant available for this?

I guess this is what we really need to have at hand if someone brings this up:

"The walker is 6.3 times (or 626 percent) more efficient than a car with a solo driver."

I would just round it to "six times more efficient." A bike would be even more efficient, of course.

Ah, this topic keeps coming up in my discussion.  Here's my attempt to further confuse the subject and drive everyone from their computer screaming.

Consider whether you are wasteful in the amount you eat.  If you eat 3,000 kcal a day (2,200 is the FDA recommendation) you're pretty much wasting the energy if you sit and drive a car.  However, the same meals would give you enough to do all that walking or biking, at no extra food cost.  So, by this measurement, walking to work is an infinite improvement over driving.

Peel back the layers of calculation and speculation and there's still one thing we're assuming: the food is grown using fossil fuels.  Well, if you buy locally grown organic produce, or animal raised the same way, your efficiency is going to be much, much better.

One way to seek the ultimate walk-vs-drive ratio is to look at global population.  Our present population of 6.5 billion is a result of fossil fuels, directly or indirectly.  Before the use of oil, gas, coal, peat, etc. the world population was around 300-400 million and either walked or used "organic" tools like horses and plows made of wood.  So by measure of populations the benefit of doing anything "organically" versus using fossil fuels to do the same thing is between 15:1 and 20:1.