To rephrase your question, you are wondering how a tax on the stupid (impatient, distracted, harassed, tired) could collect so much money? Does it seem less surprising expressed in that form?
There's a LOT to be gained from exercise, as long as you aren't expecting miraculous reduction in weight. About 5 years ago I ramped up to 50 miles/week on my bike. I rapidly lost 20 pounds -- but not a pound since then. However, I have not gained any weight, either.
On the plus side, my achy joints (knees, back) don't ache so much, and in the winter I can shovel snow till my arms are noodles and my hands feel like a ran a truck over them. And all my blood numbers moved to the good side.
Cannot establish cause and effect, yet it is another in a long strong of amazing coincidental correlations of exercise and reduced mortality.
I have, however, heard a somewhat more authoritative confirmation of approximately your assertions about insulin sensitivity, from a bona-fide microbiologist who has been studying diabetic metabolism in recent years. He didn't say anything about high-intensity stuff, he just said, "use the muscles". And the fact that all these other studies were not necessarily studying high intensity exercise (stuff like walking, bicycling), perhaps it is helpful, but it is not the only helpful thing.
Or ride a bike to work. If it only takes you twice as long by bike as by car (not always true, but often true), then the net time you spend exercising is only 46 minutes per week (or half of whatever time you spend). Bonus if you can arrange to ride your bike on the days that there are usually traffic jams, because you can do better than (less than) twice as long, plus the schadenfreude of passing stopped traffic on your bicycle.
I would think that (a) people overestimate how much they exercise and (b) exercise is still good for you. There was a Danish study of mortality rates and physical activity, and various forms of (self-reported) exercise looked good, but riding a bicycle to work looked really good. I don't think that biking is any better than any other form of aerobic exercise, but if you bike to work, you do it, or you don't. And you don't quit halfway to work. Which is to say, that the self-reporting of biking to work, was probably more accurate than the self-reporting of "oh I get lots of exercise".
Don't think this is the case. Other studies of exercise and longevity show decreased mortality, "adjusting for other risk factors", and weight is surely one of the other risk factors. However, the fact that exercise tends to also move those risk factors in the right direction, seems to imply (given my imperfect understanding of these things) that to the extent that the bad scores on "other risk factors" might be caused by lack of exercise, that exercise is probably better than its conservatively adjusted effect.
Yup. If your plan is to buy low and sell high, first you have to buy low. That means, invest when the economy looks like crap, against the future when you can use your investment to advantage.
And I would add, having once worked on a business plan for a startup, brains, especially brains doing software development, are relatively cheap. The infrastructure required to document/market/advertise/sell/support the product once you decide to make money with it, is terrifying. The guy who builds the better mousetrap and gets the path beaten to his door, is the guy who spent a ton of money on marketing and advertising ("Four tips to a dead mouse!" "Your exterminator doesn't want you to know these mouse-catching secrets!").
Investing in a semiconductor fab, now THAT takes nerve.
Additional data, not entirely consistent with other sources: http://www.engineeringtoolbox.com/met-metabolic-rate-d_733.html . Their estimate for (slow, 2km/h) walking seems high -- at 90% above resting, it appears to still work out to 54 kCal/mile incremental, about the same as the Bicycling Science estimate for 4 mph. (.9 * 1h/2km * 75 kCal/h * 8km/5mi). This could still be consistent with the perception of reduced effort, since you are in fact expending that energy more slowly.
They assert that merely standing consumes 20% more energy than sitting, and about 50% more than "reclining". If the cyclist plays the recumbent card, victory is assured:-).
I thought it was restricted to commuting, you originally mention "travel" and "busses". And later "showering" and co-workers. At any speed vaguely appropriate for a commute, walking is far less efficient than cycling, and gives the option of being not too sweaty when you arrive at work, relative to cycling.
And to the extent that we also need exercise (and we all do, it's just a question of whether we get enough of it), you need to account for that time, also.
The most efficient speeds of cycling and walking, if we are not required to account for our resting metabolic rate, are infinitely slowly. Friction losses in both cases approach zero. In the case of the bicycle, you would need to convert to a tricycle somewhere around 1 or 2 mph so that the energy needed to balance at low speeds does not go up. Adding the 3rd wheel will increase the energy required by less than 50%; however, in the limit, a 150% of zero, is still zero.
So there is your answer, with no time constraints. They're equally efficient, at zero incremental calories per mile, that is never, ever tranversed. It's not a very sensible one.
If, however, you add RMR to the energy mix, you DO get sensible definitions of minimum energy per mile, because of the 75kCal divided by mph RMR contribution . I don't know exactly what it is for either walking or bicycle, but I do know, from the points that have been given, that the minimum energy per mile for a bicycle is lower than the minimum energy per mile for walking. It's a math problem, you can do it. Just make standard assumptions about incremental energy cost falling to zero at zero mph, and choose a sensible curve fit, and that's what you will get. As I said -- if incremental energy walking at 3mph is only half of walking at 4mph, and you add the RMR, you're still worse than cycling.
Your assumptions I think assume no time constraints. My commute to work is 20 miles, round trip. That's a little less than two hours, cycling in traffic, a little less than an hour, driving in traffic. At a 4mph walk, 5 hours. I don't have those three hours. At an even more "efficient" slower walk, even more hours. Your definition for "most efficient travel" allows me to walk infinitely slowly -- you need to set a lower speed bound, else there is no solution, and certainly no sensible solution.
There is the additional issue of needing a certain amount of somewhat more energetic exercise than just "base rate" in order to maintain health.
It's a multi-factor optimization, including time, energy consumption, cost, exercise, and sweat. Adding bicycling to the mix makes a satisficing result pretty easy to attain. Driving alone does not, and adding walking doesn't do it, either. Assuming at least 4 hours of exercise, plus commuting time to work, cycling provides the best solution, at 4 + 3 = 7 hours (2 bicycle commutes, 3 car commutes, includes 4 hours exercise). Walking gives 9 hours (1 walking commute, 4 car commutes, includes 5 hours exercise). Furthermore, cycling uses far less energy than the walking alternative, since walking has me driving an additional day. The fact that bicycling also moves me through the air, increasing sweat's effectiveness at cooling me, means that a given level of exertion (required for exercise), I will sweat less than if I were walking.
At least one of my colleagues would not hesitate to tell me if I were stinky, same for my wife.:-)
I think you have the "just don't get it" backwards. I talked to a guy last week with a homemade cargo bike, he put an e-assist on to make life easier with heavy cargo. An 800 watt e-assist. It was heavy, sure, but not that heavy. I am good for maybe 200 watts sustained, and I am big. Across an intersection (0-16mph), he beats sports cars. China is apparently going ape for electric 2-wheelers, with no human inputs, but nonetheless small and efficient and not too fast. Put three wheels on it to account for poor balance, and there you go. Furthermore, I ride a cargo bike (human-powered), often with 50 lbs of cargo, and e-assist usually weighs well less than 50 lbs -- therefore, e-assist does not make the bike too heavy for human power (assuming I am human). I ride uphill with 100lbs of cargo (aka, lazy child) often enough.
The best intersection for bicycles with bicycles is rotaries, since no stop is usually required, and stopping is what cyclists like to avoid. People on bikes are not interested in crashing, so if they can avoid a crash, they usually will, even if they do so using other rules than the official ones. Bicycle rules tend to take the form of "ride as if you are almost invisible" -- this is not a rule of law, but it tends to lead to safer riding. We can also look to the Netherlands, where bicycle ride shares exceed 50% in some places, and they have the safest cycling on the planet. This is partly a matter of selection effect (the US cycling experience selects jerks like me, and worse) and partly a matter of infrastructure design (they made it easy to follow the rules, and they optimized for bicycles so that they do not suffer gratuitous delays). You put "ordinary people" on bicycle in large numbers, they are much more likely to obey the law, so the carnage that you expect does not occur when cycling is scaled up. (And actually, I do usually obey the law, but very creatively.)
You claim to be a "realist" and make confident claims about the non-existence of things that I have seen either with my own eyes or on various videos that nuts like me have made. I cannot help but think that there are options you don't know about. There are surely reasons to be pessimistic, but they are entirely social, because of our crazy love for the rut that we are currently in. Technically, we can build a low-energy vehicle, battery-powered, for your mom. These things are available right now. In our current world-O-cars, I would not expect her to use such a vehicle, not because the vehicle itself is inadequate, but because the roads are full of impatient and careless people in cars, and she would not feel safe, and she probably would not be that safe.
The absolute minimum energy expenditure for walking is set by your resting metabolic rate, which is what I used. We burn about 75 kCal/hour. That means that if you are walking at 3mph, IF YOUR INCREMENTAL ENERGY EXPENDITURE WAS ZERO, you would still burn 25 kCal/mile. A cyclist, at 4mph, accounting for both resting and cycling energy, consumes only 22.5 kCal/mile. Cycling wins, even against a hypothetical zero-effort 3mph walk. The problem with walking is that it is just too slow, and you don't get to amortize your base rate across enough miles. Walk slower, the base rate cost only goes up.
And further, suppose that walking at 3mph has an incremental energy cost that is only half that of walking 4mph. That's still 44 kCal/mile, all by itself. Add the resting contribution, you get 69 kCal/mile -- much more than cycling 15mph.
You sweat a good deal less when your sweat is evaporating; the amount you sweat is determined by how much is needed to keep you cool, and in a breeze, less sweat is adequate. So yes, dried sweat, but a much smaller amount. Done right, in non-Southern climates, you don't usually need a shower.
And do note, I am someone who has bicycled in Florida, in Texas, in Silicon Valley, and in the Boston area. I am well acquainted with sweat, and I know when I have sweat so much that a shower is necessary, and when I have not (if nothing else, I can check my clothing afterwards when I do take a shower and have joined the ranks of the squeaky-clean). I have a ten mile commute, I do this in all weather. If you ride ten summer miles anywhere along the Gulf Coast, you will sweat, no doubt. But it is not always summer, and not all places are as hot and humid as the Gulf Coast. And I did once commute by bicycle, in Houston, in the summer, with no showers. It was under two miles, and I left early each morning, rode very slowly, and tried to coast from shade puddle to shade puddle. It was faster than walking, and less sweaty.
I don't think it's laziness that makes people put their bikes on busses. I had the dumb luck to race when I was a kid; I got very good at bike handling, and very comfortable in traffic. I'm over 50 now, and I still practice bike handling skills, because you never know (principally, no-hands through pot-holes). I am several standard deviations out, in terms of comfortable-in-traffic. If someone doesn't know a route that feels safe to them (either because there is none, or they did not find it, or are especially timid in traffic), then they're a likely candidate for tossing a bike onto the front of a bus.
I assume, if a car-free future ever arrives (and seriously, compare our cultural support for the automobile, with those few Google hits. Look at magazines like Road and Track, Car and Driver, the AAA, (US) national support multiple times over the years for financially troubled automobile companies), for people who are truly infirm, that there will be alternatives (I know about osteoporosis, good friend's grandmother had it, it was awful). I don't think it needs to weigh a ton, doesn't need to be six feet wide, and doesn't need to be capable of traveling at 100mph. There are already bike-y alternatives, but they are expensive boutique-y things and not widely known. Check out the bike in this photo. Another model might be some of the wheelchairs that Dean Kamen has invented; he also invented the Segway, but I saw a standing wheelchair at our post office, and it is an order of magnitude cooler. The point is not to get everyone onto bicycles -- the point is to shrink the size and weight of the vehicles so low that they can be run with no more power than a human can provide. Once you've done that, the energy requirements are so low, that you can hardly help but be green. It doesn't mean you require that it be humans that provide the power. Most of this stuff is already well past prototype, often for sale in the "real" world.
I am not so sure that bicycles need the same laws as cars to be safe. If cars rarely traveled more than 20mph, had a GVW that was rarely more than 300lbs, and always had the driver's eyes and ears unobstructed, cars might not need the current laws to be safe, either. What looks like a near miss to you on your porch, might be no big deal to the cyclists on the ground (then again, Boston drivers on bicycles are still Boston drivers, only with a lower expectation of getting a ticket). I know, on a local bike path, that there is often 2-way traffic 3 wide in 12 feet of pavement, and sometimes 4 wide. I tend to give people lots of room not because I need to it to feel safe, but because I don't want to scare them. Compare pedestrian deaths attributed to autos and light trucks, to those attributed to "pedalcycles" (this, from nationmaster.com). It's 3000:1 (keeping in mind that the trip share is about 100:1, so it is closer to a factor of 30, per vehicle). Figures from Britain are similar (saw them, don't have a reference handy). Measured by results, rather than by adherence to the laws, it appears that cyclists are the safety experts, no matter how horrible it looks from your porch.
Perhaps (man, these comment windows are squirrelly), but if you slow down to 2mph, your resting rate starts to get you -- whatever the lower incremental energy cost is, your resting energy is now 35 kCal/mile. That is more than the total energy cost of cycling at 10mph -- 25 kCal/mile incremental, plus 75/10 resting = 32.5 kCal/mile.
This stuff has been studied. Bicycling is the most efficient way to travel, unless you spend a really long time in orbit (that first 100 miles is a killer, after that, it's just coasting).
I don't think you are thinking about the numbers very carefully. A cyclist can travel the same speed at a lower energy expenditure (4mph, I included that one). Therefore, less sweat. I haven't done the math to figure the speed at which the per-hour energy expenditure of the cyclist is equal to walking at 4mph, but I know it is more than 4mph. Furthermore, the wind from pedaling forward has a decent cooling effect, so if you can taper your speed down as you approach your goal, you should be able to go even faster without sweat. I know, empirically, that stopping dead from 15mph on a hot day, immediately transforms you from comfortably cooled by the wind, to puddle-O-sweat, so that doesn't work.
And I did once take a stab at the energy of heating water for a shower, and it's not small. It makes sense to not go flat-out on your commute to work; I don't *usually* need to take a shower when I arrive at work (I don't live in Houston or Atlanta, however).
Walking IS less inefficient compared to cycling. According to Bicycling Science, 3ed, p. 166, cycling 15mph is about 24 kCal/km (38/mi), walking 4mph is about 55 kCal/km (88/mi). Cycling at 10mph is 15.6 kCal/km (25), 4mph is 8.4 kCal/km (13.5) (assuming you don't waste too much energy staying balanced).
These figures are "incremental above resting". Resting metabolic rate appears to be about 75 kCal/hour, so the 4mph figures for walking and cycling are 19 kCal/mile higher -- 107 and 22.5, respectively. At 15mph, resting contribution is only 5 kCal/mile (43 kCal/mile total).
I hope this helps. None of this is news; all the data and studies are out there, waiting for someone to read them. Two books written decades ago covered all of this -- Food, Energy, and Society by Pimentel, and Bicycling Science by Wilson.
The food energy of bicycling is not large. Considering only the bicyclist, and substituting vegetable oil for gasoline, 600mpg (50 kCal/mile, roughly). The cost of generating that food varies enormously, from 100% beef protein (end-to-end mpg, 15), to oats (end-to-end mpg, 3000, if cooked carefully). Usually, the bicycle wins handily. If you merely consume 85% lean beef (and don't discard the fat), you're at 30 end-to-end mpg. Drinking 1% milk gives you effectively 145mpg (fossil-fuel gallons, not milk gallons; 1% milk is 16 servings/gallon at 110 kCal/gallon = 1760 kCal/gallon = 35 miles/milk-gallon).
I am not sure the assumptions are "false", or rather, you yourself are making assumptions. If the alternative to a bus, is to drive a car (your assumption), then yes, you need more roads, and (as you say) more cars. But if the alternative is something somewhat smaller than a car (electric scooter, or a bicycle), then you don't need more roads (depends -- a completely full bus is more compact than the same number of people on bicycles, but the bicycles have the option of spreading themselves out a bit in time and across alternate routes).
Around here (Boston), the really disabled, don't always take the big city bus, since they cannot even walk to the stop; there are instead smaller vans that go point to point.
What you get from a bike rack on a bus, is either (a) a way to deal with a longer ride than someone wants to make, or (b) a way to get across a place where the traffic is very unpleasant or unsafe for bicycles. The best example of this is probably the Caltrain train car, where you might bike to a Caltrain station, ride the train dozens of miles up or down the San Francisco peninsula, and then get out and ride some more. This also illustrates the potential downside of transporting bicycles; in the space used by 40 bicycles and their riders, you could probably fit 120 pedestrian passengers, if the demand was that high (but it usually isn't -- and I'm estimating 20 rows, times 4 across on the first level, times 2 across on the upper level, in one half of a train car).
I think your pessimism about the future is unwarranted. First, nobody is seriously talking about getting rid of all the cars. In the Netherlands, they still have cars, so we're a long way from that. Second, suppose we did? Do you really think that those are your only choices? Electric assist (it is approximately as green as human-powered cycling, especially when you have non-fossil electricity options) is very popular in China (there, it's electric scooters) and I understand it is growing in use in Northern Europe (in the Netherlands, in particular). If you can balance, but have no strength, an e-bike, if your balance is not so good, an e-trike. And technically, this is not pie-in-the-sky at all; you can buy a cargo trike, with an electric assist option, today. I'm sure it's not cheap, because you're buying from a made-in-the-USA boutique bike company, but you can buy it now. In the Netherlands, for a bit of money, you can buy a faired, recumbent tricycle, that also includes some cargo capacity (130 liters, plus option of a trailer hitch).
Your expenses do not match mine (I'm at 2500+ mi/year). I true my own wheels, and for my derailer-driven bikes, I go with commodity chains and cassettes, and I patch tubes many times before discarding them. These things save a fair amount of money. If I didn't live in the land of winter salt-N-sand, I would get a much longer life out of my drive trains. Also, I make a point of not crashing, which saves on torn clothing.
You also need to be aware of the Insane Bicycle Markup -- the fact that you mention "torn gear" suggests that you may be in that market. Things like lights cost an order of magnitude more than they should (a 200 lumen headlight, the regulator costs under $20, a mounted LED, $7.50, and a lens, $2.50, all retail prices quantity one. Anyone manufacturing these would pay half or less). This can distort your cost-based carbon footprint calculations.
Don't know where you live, or how much you sweat, which affects your speed/sweat tradeoff, but there are some other options. One, is to look for another job. I know, not in this economy, but it's something to keep in mind, should an opportunity arise.
Two, somewhat expensive, but workable, is to get an electric assist for your bicycle. There's a variety of these, they generally will get you to 20mph (regulations limit this), more if you know how to hack them (not that I would ever recommend this, oh noes). 20mph-assisted gets you to about 8-10 miles, depending on stop signs and stop lights, and in some cases, traffic (if there's traffic, and no good place to pass on the right, you can get stuck behind a car -- they take up the whole road).
Three, and this may go hand-in-hand with the bicycle assist, is to ditch the car altogether. This may save you enough money to move closer to work, and have some left over. That option may require a Bicycle of Unusual Size, aka, a cargo bike, so that you can handle usual shopping and the occasional passenger. In some cases, you may be able to convert the parking spot that usually goes with housing, into something that you can rent out to other people who have an additional car and no place to put it, and recoup some of that money.
I think you need to back this up with numbers. There's an awful lot of diseases-of-the-unfit that cycling makes less likely, to the point that in one Danish study, non-bicycle commuters were observed to have a 39% higher mortality rate. Could just be a coincidence, of course. In my own anecdotal case, riding a bicycle allows me to avoid various forms of medical care -- in my 20s, with a cranky knee, whose symptoms were relieved by cycling, the knee doctor offered the advice, "I can cut you open, or you can ride your bike, your choice." Now, it tends to relieve symptoms of arthritis in general (on those joints that get flexed-not-impacted by riding) as well as keeping my weight down and my blood chemistry in a good place (we've got before/after comparisons, it's pretty striking).
Your cost of food-production estimates are wildly overstated. This has been addressed by people like Pimentel, and if you avoid meat, you are probably doing okay. As a general rule, the cost of a food item sets an upper bound on the energy required to produce it. So for example, a gallon of milk costs about the same as a gallon of gasoline -- so it could not take more than a gallon of gasoline's worth of energy to produce that milk (this ignores taxes, etc, but round numbers). A gallon of 1% milk has enough energy to fuel a cyclist for about 150 miles -- 2% and whole milk, much more (the rule is 50kCal per mile). So the bicycle beats a car there, pretty easily.
It's also possible to do better -- oats, in particular, yield 5 kCal of food energy for every 1 kCal of fossil fuel input (units are a bear, I know), so that if you cook them carefully (not usually the case) you can get an effective mpg of 3000. Cooking them carelessly lowers that to 2000 or even 1000mpg.
And it's been a few months since I last saw Manhattan, but the guns must be carefully hidden, because I didn't see any, and it was bloody expensive, which normally suggests that people wish to be there, not the opposite.
I hope, perhaps with little foundation, that by the time e-cars are the majority vehicle, that we will also have reliable self-driving cars, and they would be more like robotic taxi-jitneys. You call for a ride from A to B, a car shows up, with some other people already in it, maybe you pick up another on the way, and get dropped off. Robo-cars sit idle during slack periods, more run during rush hour. Closer to point-to-point, less wear and tear on the roads, also more efficient because of the multiple passengers. That's what I'd hope, anyway.
I think the problem with roads, trucks, and cars, is that the trucks do the initial damage, but unless you (spend the money to) watch for new cracks, they'll get out of hand fast, and the first day it rains, cars finish the damage. And think of the money you can save by deferring road maintenance, eh? So it's not just trucks, unless you sign on to healthy spending on preventive road maintenance, and that's not fashionable nowadays.
Your other choice is to just ride a bike -- a cargo bike is plenty capable for most trips, doesn't necessarily need a road, and doesn't tear the road up, either (lighter than any car, the lower speed and narrower tires jet less water into cracks).
Slashdot Mirror
To rephrase your question, you are wondering how a tax on the stupid (impatient, distracted, harassed, tired) could collect so much money? Does it seem less surprising expressed in that form?
There's a LOT to be gained from exercise, as long as you aren't expecting miraculous reduction in weight. About 5 years ago I ramped up to 50 miles/week on my bike. I rapidly lost 20 pounds -- but not a pound since then. However, I have not gained any weight, either.
On the plus side, my achy joints (knees, back) don't ache so much, and in the winter I can shovel snow till my arms are noodles and my hands feel like a ran a truck over them. And all my blood numbers moved to the good side.
Cannot establish cause and effect, yet it is another in a long strong of amazing coincidental correlations of exercise and reduced mortality.
I have, however, heard a somewhat more authoritative confirmation of approximately your assertions about insulin sensitivity, from a bona-fide microbiologist who has been studying diabetic metabolism in recent years. He didn't say anything about high-intensity stuff, he just said, "use the muscles". And the fact that all these other studies were not necessarily studying high intensity exercise (stuff like walking, bicycling), perhaps it is helpful, but it is not the only helpful thing.
Or ride a bike to work. If it only takes you twice as long by bike as by car (not always true, but often true), then the net time you spend exercising is only 46 minutes per week (or half of whatever time you spend). Bonus if you can arrange to ride your bike on the days that there are usually traffic jams, because you can do better than (less than) twice as long, plus the schadenfreude of passing stopped traffic on your bicycle.
I would think that (a) people overestimate how much they exercise and (b) exercise is still good for you. There was a Danish study of mortality rates and physical activity, and various forms of (self-reported) exercise looked good, but riding a bicycle to work looked really good. I don't think that biking is any better than any other form of aerobic exercise, but if you bike to work, you do it, or you don't. And you don't quit halfway to work. Which is to say, that the self-reporting of biking to work, was probably more accurate than the self-reporting of "oh I get lots of exercise".
Don't think this is the case. Other studies of exercise and longevity show decreased mortality, "adjusting for other risk factors", and weight is surely one of the other risk factors. However, the fact that exercise tends to also move those risk factors in the right direction, seems to imply (given my imperfect understanding of these things) that to the extent that the bad scores on "other risk factors" might be caused by lack of exercise, that exercise is probably better than its conservatively adjusted effect.
Yup. If your plan is to buy low and sell high, first you have to buy low. That means, invest when the economy looks like crap, against the future when you can use your investment to advantage.
And I would add, having once worked on a business plan for a startup, brains, especially brains doing software development, are relatively cheap. The infrastructure required to document/market/advertise/sell/support the product once you decide to make money with it, is terrifying. The guy who builds the better mousetrap and gets the path beaten to his door, is the guy who spent a ton of money on marketing and advertising ("Four tips to a dead mouse!" "Your exterminator doesn't want you to know these mouse-catching secrets!").
Investing in a semiconductor fab, now THAT takes nerve.
Additional data, not entirely consistent with other sources: http://www.engineeringtoolbox.com/met-metabolic-rate-d_733.html . Their estimate for (slow, 2km/h) walking seems high -- at 90% above resting, it appears to still work out to 54 kCal/mile incremental, about the same as the Bicycling Science estimate for 4 mph. (.9 * 1h/2km * 75 kCal/h * 8km/5mi). This could still be consistent with the perception of reduced effort, since you are in fact expending that energy more slowly.
They assert that merely standing consumes 20% more energy than sitting, and about 50% more than "reclining". If the cyclist plays the recumbent card, victory is assured :-).
I thought it was restricted to commuting, you originally mention "travel" and "busses". And later "showering" and co-workers. At any speed vaguely appropriate for a commute, walking is far less efficient than cycling, and gives the option of being not too sweaty when you arrive at work, relative to cycling.
And to the extent that we also need exercise (and we all do, it's just a question of whether we get enough of it), you need to account for that time, also.
The most efficient speeds of cycling and walking, if we are not required to account for our resting metabolic rate, are infinitely slowly. Friction losses in both cases approach zero. In the case of the bicycle, you would need to convert to a tricycle somewhere around 1 or 2 mph so that the energy needed to balance at low speeds does not go up. Adding the 3rd wheel will increase the energy required by less than 50%; however, in the limit, a 150% of zero, is still zero.
So there is your answer, with no time constraints. They're equally efficient, at zero incremental calories per mile, that is never, ever tranversed. It's not a very sensible one.
If, however, you add RMR to the energy mix, you DO get sensible definitions of minimum energy per mile, because of the 75kCal divided by mph RMR contribution . I don't know exactly what it is for either walking or bicycle, but I do know, from the points that have been given, that the minimum energy per mile for a bicycle is lower than the minimum energy per mile for walking. It's a math problem, you can do it. Just make standard assumptions about incremental energy cost falling to zero at zero mph, and choose a sensible curve fit, and that's what you will get. As I said -- if incremental energy walking at 3mph is only half of walking at 4mph, and you add the RMR, you're still worse than cycling.
Your assumptions I think assume no time constraints. My commute to work is 20 miles, round trip. That's a little less than two hours, cycling in traffic, a little less than an hour, driving in traffic. At a 4mph walk, 5 hours. I don't have those three hours. At an even more "efficient" slower walk, even more hours. Your definition for "most efficient travel" allows me to walk infinitely slowly -- you need to set a lower speed bound, else there is no solution, and certainly no sensible solution.
There is the additional issue of needing a certain amount of somewhat more energetic exercise than just "base rate" in order to maintain health.
It's a multi-factor optimization, including time, energy consumption, cost, exercise, and sweat. Adding bicycling to the mix makes a satisficing result pretty easy to attain. Driving alone does not, and adding walking doesn't do it, either. Assuming at least 4 hours of exercise, plus commuting time to work, cycling provides the best solution, at 4 + 3 = 7 hours (2 bicycle commutes, 3 car commutes, includes 4 hours exercise). Walking gives 9 hours (1 walking commute, 4 car commutes, includes 5 hours exercise). Furthermore, cycling uses far less energy than the walking alternative, since walking has me driving an additional day. The fact that bicycling also moves me through the air, increasing sweat's effectiveness at cooling me, means that a given level of exertion (required for exercise), I will sweat less than if I were walking.
At least one of my colleagues would not hesitate to tell me if I were stinky, same for my wife. :-)
I think you have the "just don't get it" backwards. I talked to a guy last week with a homemade cargo bike, he put an e-assist on to make life easier with heavy cargo. An 800 watt e-assist. It was heavy, sure, but not that heavy. I am good for maybe 200 watts sustained, and I am big. Across an intersection (0-16mph), he beats sports cars. China is apparently going ape for electric 2-wheelers, with no human inputs, but nonetheless small and efficient and not too fast. Put three wheels on it to account for poor balance, and there you go. Furthermore, I ride a cargo bike (human-powered), often with 50 lbs of cargo, and e-assist usually weighs well less than 50 lbs -- therefore, e-assist does not make the bike too heavy for human power (assuming I am human). I ride uphill with 100lbs of cargo (aka, lazy child) often enough.
The best intersection for bicycles with bicycles is rotaries, since no stop is usually required, and stopping is what cyclists like to avoid. People on bikes are not interested in crashing, so if they can avoid a crash, they usually will, even if they do so using other rules than the official ones. Bicycle rules tend to take the form of "ride as if you are almost invisible" -- this is not a rule of law, but it tends to lead to safer riding. We can also look to the Netherlands, where bicycle ride shares exceed 50% in some places, and they have the safest cycling on the planet. This is partly a matter of selection effect (the US cycling experience selects jerks like me, and worse) and partly a matter of infrastructure design (they made it easy to follow the rules, and they optimized for bicycles so that they do not suffer gratuitous delays). You put "ordinary people" on bicycle in large numbers, they are much more likely to obey the law, so the carnage that you expect does not occur when cycling is scaled up. (And actually, I do usually obey the law, but very creatively.)
You claim to be a "realist" and make confident claims about the non-existence of things that I have seen either with my own eyes or on various videos that nuts like me have made. I cannot help but think that there are options you don't know about. There are surely reasons to be pessimistic, but they are entirely social, because of our crazy love for the rut that we are currently in. Technically, we can build a low-energy vehicle, battery-powered, for your mom. These things are available right now. In our current world-O-cars, I would not expect her to use such a vehicle, not because the vehicle itself is inadequate, but because the roads are full of impatient and careless people in cars, and she would not feel safe, and she probably would not be that safe.
The absolute minimum energy expenditure for walking is set by your resting metabolic rate, which is what I used. We burn about 75 kCal/hour. That means that if you are walking at 3mph, IF YOUR INCREMENTAL ENERGY EXPENDITURE WAS ZERO, you would still burn 25 kCal/mile. A cyclist, at 4mph, accounting for both resting and cycling energy, consumes only 22.5 kCal/mile. Cycling wins, even against a hypothetical zero-effort 3mph walk. The problem with walking is that it is just too slow, and you don't get to amortize your base rate across enough miles. Walk slower, the base rate cost only goes up.
And further, suppose that walking at 3mph has an incremental energy cost that is only half that of walking 4mph. That's still 44 kCal/mile, all by itself. Add the resting contribution, you get 69 kCal/mile -- much more than cycling 15mph.
You sweat a good deal less when your sweat is evaporating; the amount you sweat is determined by how much is needed to keep you cool, and in a breeze, less sweat is adequate. So yes, dried sweat, but a much smaller amount. Done right, in non-Southern climates, you don't usually need a shower.
And do note, I am someone who has bicycled in Florida, in Texas, in Silicon Valley, and in the Boston area. I am well acquainted with sweat, and I know when I have sweat so much that a shower is necessary, and when I have not (if nothing else, I can check my clothing afterwards when I do take a shower and have joined the ranks of the squeaky-clean). I have a ten mile commute, I do this in all weather. If you ride ten summer miles anywhere along the Gulf Coast, you will sweat, no doubt. But it is not always summer, and not all places are as hot and humid as the Gulf Coast. And I did once commute by bicycle, in Houston, in the summer, with no showers. It was under two miles, and I left early each morning, rode very slowly, and tried to coast from shade puddle to shade puddle. It was faster than walking, and less sweaty.
I don't think it's laziness that makes people put their bikes on busses. I had the dumb luck to race when I was a kid; I got very good at bike handling, and very comfortable in traffic. I'm over 50 now, and I still practice bike handling skills, because you never know (principally, no-hands through pot-holes). I am several standard deviations out, in terms of comfortable-in-traffic. If someone doesn't know a route that feels safe to them (either because there is none, or they did not find it, or are especially timid in traffic), then they're a likely candidate for tossing a bike onto the front of a bus.
I assume, if a car-free future ever arrives (and seriously, compare our cultural support for the automobile, with those few Google hits. Look at magazines like Road and Track, Car and Driver, the AAA, (US) national support multiple times over the years for financially troubled automobile companies), for people who are truly infirm, that there will be alternatives (I know about osteoporosis, good friend's grandmother had it, it was awful). I don't think it needs to weigh a ton, doesn't need to be six feet wide, and doesn't need to be capable of traveling at 100mph. There are already bike-y alternatives, but they are expensive boutique-y things and not widely known. Check out the bike in this photo. Another model might be some of the wheelchairs that Dean Kamen has invented; he also invented the Segway, but I saw a standing wheelchair at our post office, and it is an order of magnitude cooler. The point is not to get everyone onto bicycles -- the point is to shrink the size and weight of the vehicles so low that they can be run with no more power than a human can provide. Once you've done that, the energy requirements are so low, that you can hardly help but be green. It doesn't mean you require that it be humans that provide the power. Most of this stuff is already well past prototype, often for sale in the "real" world.
I am not so sure that bicycles need the same laws as cars to be safe. If cars rarely traveled more than 20mph, had a GVW that was rarely more than 300lbs, and always had the driver's eyes and ears unobstructed, cars might not need the current laws to be safe, either. What looks like a near miss to you on your porch, might be no big deal to the cyclists on the ground (then again, Boston drivers on bicycles are still Boston drivers, only with a lower expectation of getting a ticket). I know, on a local bike path, that there is often 2-way traffic 3 wide in 12 feet of pavement, and sometimes 4 wide. I tend to give people lots of room not because I need to it to feel safe, but because I don't want to scare them. Compare pedestrian deaths attributed to autos and light trucks, to those attributed to "pedalcycles" (this, from nationmaster.com). It's 3000:1 (keeping in mind that the trip share is about 100:1, so it is closer to a factor of 30, per vehicle). Figures from Britain are similar (saw them, don't have a reference handy). Measured by results, rather than by adherence to the laws, it appears that cyclists are the safety experts, no matter how horrible it looks from your porch.
Perhaps (man, these comment windows are squirrelly), but if you slow down to 2mph, your resting rate starts to get you -- whatever the lower incremental energy cost is, your resting energy is now 35 kCal/mile. That is more than the total energy cost of cycling at 10mph -- 25 kCal/mile incremental, plus 75/10 resting = 32.5 kCal/mile.
This stuff has been studied. Bicycling is the most efficient way to travel, unless you spend a really long time in orbit (that first 100 miles is a killer, after that, it's just coasting).
I don't think you are thinking about the numbers very carefully. A cyclist can travel the same speed at a lower energy expenditure (4mph, I included that one). Therefore, less sweat. I haven't done the math to figure the speed at which the per-hour energy expenditure of the cyclist is equal to walking at 4mph, but I know it is more than 4mph. Furthermore, the wind from pedaling forward has a decent cooling effect, so if you can taper your speed down as you approach your goal, you should be able to go even faster without sweat. I know, empirically, that stopping dead from 15mph on a hot day, immediately transforms you from comfortably cooled by the wind, to puddle-O-sweat, so that doesn't work.
And I did once take a stab at the energy of heating water for a shower, and it's not small. It makes sense to not go flat-out on your commute to work; I don't *usually* need to take a shower when I arrive at work (I don't live in Houston or Atlanta, however).
aack -- walking is less EFFICIENT.
Walking IS less inefficient compared to cycling. According to Bicycling Science, 3ed, p. 166, cycling 15mph is about 24 kCal/km (38/mi), walking 4mph is about 55 kCal/km (88/mi). Cycling at 10mph is 15.6 kCal/km (25), 4mph is 8.4 kCal/km (13.5) (assuming you don't waste too much energy staying balanced).
These figures are "incremental above resting". Resting metabolic rate appears to be about 75 kCal/hour, so the 4mph figures for walking and cycling are 19 kCal/mile higher -- 107 and 22.5, respectively. At 15mph, resting contribution is only 5 kCal/mile (43 kCal/mile total).
I hope this helps. None of this is news; all the data and studies are out there, waiting for someone to read them. Two books written decades ago covered all of this -- Food, Energy, and Society by Pimentel, and Bicycling Science by Wilson.
The food energy of bicycling is not large. Considering only the bicyclist, and substituting vegetable oil for gasoline, 600mpg (50 kCal/mile, roughly). The cost of generating that food varies enormously, from 100% beef protein (end-to-end mpg, 15), to oats (end-to-end mpg, 3000, if cooked carefully). Usually, the bicycle wins handily. If you merely consume 85% lean beef (and don't discard the fat), you're at 30 end-to-end mpg. Drinking 1% milk gives you effectively 145mpg (fossil-fuel gallons, not milk gallons; 1% milk is 16 servings/gallon at 110 kCal/gallon = 1760 kCal/gallon = 35 miles/milk-gallon).
I am not sure the assumptions are "false", or rather, you yourself are making assumptions. If the alternative to a bus, is to drive a car (your assumption), then yes, you need more roads, and (as you say) more cars. But if the alternative is something somewhat smaller than a car (electric scooter, or a bicycle), then you don't need more roads (depends -- a completely full bus is more compact than the same number of people on bicycles, but the bicycles have the option of spreading themselves out a bit in time and across alternate routes).
Around here (Boston), the really disabled, don't always take the big city bus, since they cannot even walk to the stop; there are instead smaller vans that go point to point.
Hybrid and plugin-electric automobiles change this, since they have regenerative braking.
What you get from a bike rack on a bus, is either (a) a way to deal with a longer ride than someone wants to make, or (b) a way to get across a place where the traffic is very unpleasant or unsafe for bicycles. The best example of this is probably the Caltrain train car, where you might bike to a Caltrain station, ride the train dozens of miles up or down the San Francisco peninsula, and then get out and ride some more. This also illustrates the potential downside of transporting bicycles; in the space used by 40 bicycles and their riders, you could probably fit 120 pedestrian passengers, if the demand was that high (but it usually isn't -- and I'm estimating 20 rows, times 4 across on the first level, times 2 across on the upper level, in one half of a train car).
I think your pessimism about the future is unwarranted. First, nobody is seriously talking about getting rid of all the cars. In the Netherlands, they still have cars, so we're a long way from that. Second, suppose we did? Do you really think that those are your only choices? Electric assist (it is approximately as green as human-powered cycling, especially when you have non-fossil electricity options) is very popular in China (there, it's electric scooters) and I understand it is growing in use in Northern Europe (in the Netherlands, in particular). If you can balance, but have no strength, an e-bike, if your balance is not so good, an e-trike. And technically, this is not pie-in-the-sky at all; you can buy a cargo trike, with an electric assist option, today. I'm sure it's not cheap, because you're buying from a made-in-the-USA boutique bike company, but you can buy it now. In the Netherlands, for a bit of money, you can buy a faired, recumbent tricycle, that also includes some cargo capacity (130 liters, plus option of a trailer hitch).
Your expenses do not match mine (I'm at 2500+ mi/year). I true my own wheels, and for my derailer-driven bikes, I go with commodity chains and cassettes, and I patch tubes many times before discarding them. These things save a fair amount of money. If I didn't live in the land of winter salt-N-sand, I would get a much longer life out of my drive trains. Also, I make a point of not crashing, which saves on torn clothing.
You also need to be aware of the Insane Bicycle Markup -- the fact that you mention "torn gear" suggests that you may be in that market. Things like lights cost an order of magnitude more than they should (a 200 lumen headlight, the regulator costs under $20, a mounted LED, $7.50, and a lens, $2.50, all retail prices quantity one. Anyone manufacturing these would pay half or less). This can distort your cost-based carbon footprint calculations.
Don't know where you live, or how much you sweat, which affects your speed/sweat tradeoff, but there are some other options. One, is to look for another job. I know, not in this economy, but it's something to keep in mind, should an opportunity arise.
Two, somewhat expensive, but workable, is to get an electric assist for your bicycle. There's a variety of these, they generally will get you to 20mph (regulations limit this), more if you know how to hack them (not that I would ever recommend this, oh noes). 20mph-assisted gets you to about 8-10 miles, depending on stop signs and stop lights, and in some cases, traffic (if there's traffic, and no good place to pass on the right, you can get stuck behind a car -- they take up the whole road).
Three, and this may go hand-in-hand with the bicycle assist, is to ditch the car altogether. This may save you enough money to move closer to work, and have some left over. That option may require a Bicycle of Unusual Size, aka, a cargo bike, so that you can handle usual shopping and the occasional passenger. In some cases, you may be able to convert the parking spot that usually goes with housing, into something that you can rent out to other people who have an additional car and no place to put it, and recoup some of that money.
I think you need to back this up with numbers. There's an awful lot of diseases-of-the-unfit that cycling makes less likely, to the point that in one Danish study, non-bicycle commuters were observed to have a 39% higher mortality rate. Could just be a coincidence, of course. In my own anecdotal case, riding a bicycle allows me to avoid various forms of medical care -- in my 20s, with a cranky knee, whose symptoms were relieved by cycling, the knee doctor offered the advice, "I can cut you open, or you can ride your bike, your choice." Now, it tends to relieve symptoms of arthritis in general (on those joints that get flexed-not-impacted by riding) as well as keeping my weight down and my blood chemistry in a good place (we've got before/after comparisons, it's pretty striking).
Your cost of food-production estimates are wildly overstated. This has been addressed by people like Pimentel, and if you avoid meat, you are probably doing okay. As a general rule, the cost of a food item sets an upper bound on the energy required to produce it. So for example, a gallon of milk costs about the same as a gallon of gasoline -- so it could not take more than a gallon of gasoline's worth of energy to produce that milk (this ignores taxes, etc, but round numbers). A gallon of 1% milk has enough energy to fuel a cyclist for about 150 miles -- 2% and whole milk, much more (the rule is 50kCal per mile). So the bicycle beats a car there, pretty easily.
It's also possible to do better -- oats, in particular, yield 5 kCal of food energy for every 1 kCal of fossil fuel input (units are a bear, I know), so that if you cook them carefully (not usually the case) you can get an effective mpg of 3000. Cooking them carelessly lowers that to 2000 or even 1000mpg.
And it's been a few months since I last saw Manhattan, but the guns must be carefully hidden, because I didn't see any, and it was bloody expensive, which normally suggests that people wish to be there, not the opposite.
I hope, perhaps with little foundation, that by the time e-cars are the majority vehicle, that we will also have reliable self-driving cars, and they would be more like robotic taxi-jitneys. You call for a ride from A to B, a car shows up, with some other people already in it, maybe you pick up another on the way, and get dropped off. Robo-cars sit idle during slack periods, more run during rush hour. Closer to point-to-point, less wear and tear on the roads, also more efficient because of the multiple passengers. That's what I'd hope, anyway.
I think the problem with roads, trucks, and cars, is that the trucks do the initial damage, but unless you (spend the money to) watch for new cracks, they'll get out of hand fast, and the first day it rains, cars finish the damage. And think of the money you can save by deferring road maintenance, eh? So it's not just trucks, unless you sign on to healthy spending on preventive road maintenance, and that's not fashionable nowadays.
Your other choice is to just ride a bike -- a cargo bike is plenty capable for most trips, doesn't necessarily need a road, and doesn't tear the road up, either (lighter than any car, the lower speed and narrower tires jet less water into cracks).