How are you defining efficiency here? Is walking really more efficient than cycling? I would put walking as the least efficient manual powered methods mentioned.

Aside: I used to unicycle to work, and I have to say that it was both fantastic and much faster than walking while on a 27.5" wheel.

Bicycles are like 98% in terms of distance/effort so even when you factor in the manufacture/materials it seems like it's pretty hard to improve on.

When you account for calorie transport it's possible the e-bike comes out on top, especially if charged from a local renewable electricity source.

[]: https://pedalchile.com/blog/cycling-vs-walking

at a micro level that's probably true, but from a public policy perspective, I'm willing to bet that regular bikes effect to increase fitness probably saves more carbon in the long run (healthcare is pretty calorie intensive).

Most ebikes you have to pedal to make them go. Some just push the throttle, but most are motor assist but if you don't pedal you don't go. As such most ebikes give the same fitness benefit but let you go faster (read farther). My ebike almost forces me to work harder than the regular bike as because it is heavy it feels like it doesn't coast as nice as the regular bike, and so I'm pedaling more. (part of this is probably I'm going faster and so wind resistance is lowing me down more - but to me it feels like I have to work harder to make the ebike work, in return I go farther on it)

> As such most ebikes give the same fitness benefit but let you go faster

This is simply not true. A pedal-assist bike will go faster with the same amount of W put into the pedals, yes. But will people put in the same amount of W if 60 % will get you to your "target speed"? I doubt it. And then you get less health benefits for the same distance traveled.

On my 8 kilometer commute I average 150 W. Not because I use it as exercise. That's just where I find my comfortable level of output. Every time I've ridden on ebikes I've put in much, much less effort. I'd be surprised if I put in even a third of the energy. That's great if you just need a mode of transport. Bikes are practical, efficient, and planning for them improves cities. Even ignoring the potential health benefits. But claiming that a pedalassist bike gives the same fitness benefits just doesn't pass the smell test.

I can only state for myself that I'm putting more effort in (since I can feel the bike slow down more when I don't). Plus the ebike allows trips that because of distance I wouldn't use the regular bike for.

From a public policy perspective, we've had bikes for eons and usage has always been minuscule and now we have ebikes and usage has jumped. So that particular experiment has already been run.

Yup, IIRC in terms of kJ/km cycling is ~4x more efficient than walking (on flat surface). I guess they must be talking about the energy used in production, etc.

It's closer to 6x.

I mean, the number will really depend on how fast people are biking. Over 20mph, efficiency starts to really take a hit. Unless you use some sort of crazy shell.

Cycling anywhere near 20mph is beyond most peoples physical capabilities... with the small exception of steep downhills where the energy is "free" (at least compared with walking where you capture none of it) anyways.

I used to aim for an average 20mph over my rides when I was in peak fitness, so putting it “beyond … physical capabilities” is nonsense.

"Most people" aren't in peak fitness...

What does a salmon have in common with a man on a bicycle?

They are both Pareto-efficient. Here's a chart of cost of transport (calories/gram/km) vs weight (kg) comparing a salmon vs a bicycle vs a jet fighter etc: https://www.bike.nyc/wp-content/uploads/2017/04/efficiency-g...

Fun! But how to read the Y axis? Why does it start from 1 twice?

I think it starts at .1 at the bottom, but the scan quality makes it difficult to discern the decimal.

[delayed]

When is that measuring the salmon? Surely, calories per gram per kilometer is very high if you're swimming upstream and low when you're going downstream, right? Is this when they're in the ocean phase?

There is another dimension to add: how far do you really "need" to go and how frequently. And why it is so? Remote working vs commuting, local/nearby enough shopping vs long distance for supermarkets, going yourself vs (maybe electric) delivery.

If everything around you is built with base assumption that you must have a car, then the optimization was done by someone else with a different definition of efficiency.

Yes. This is the difference between mobility and access. You can watch a movie by driving to Blockbuster in a SUV and physically picking up an optical disc. Or in an EV. You could bike there. Or get it mailed. If you watch on Netflix you access the commodity without any transportation at all.

Life is a compromise. I'd love to own 100 square miles of land, with my front door on New Yorks Time's square. That isn't physically possible, but it is what I want in the ideal world. (I don't live near New York so I don't know if times square is really where in New York I'd want to live, but it is an iconic place that at least gives the sense of what I mean - you could pick downtown of most large cities). Cars enable more people to have both the benefit of rural life while also getting the benefits of the city.

This isn't unique to cars - trains could give the same, but we already have a road network.

> That isn't physically possible, but it is what I want in the ideal world.

I think the same can be said (to a lesser degree maybe) about cars, which are very space inefficient. With enough sprawl and a certain density, e.g. in Toronto, it's just gonna be traffic for every one.

Not exactly. Sprawl means you can't reasonably reach the entire city, but low density sprawl and cars mean you can reach enough of a city to consider it all the advantages of a city. Toronto loses out because they have a dense city center, downtowns have to be torn down for the sprawl model to work - people who get a new job may have to move elsewhere in the city since the new job isn't close to the old (unlike when all jobs were downtown) However since you are still "close" you can visit old friends and family on weekends - it will be a long drive but you don't make that trip often so it is reasonable.

Cars don't enable many people to own 100 square miles - but I can get pretty close if I settle for 5 acres in an exurb. Many find that a single family house gives them close enough (they get a small garden - most likely grass they mow weekly - which is all they really want). But again it is a compromise. If we had science fiction technology (terraform Mars and Venus; teleporters) that 100 square miles might be reasonable.

I did not make my point clear, and that's my bad.

Torotno exists, so of course car dependency is somewhat feasible in real life. The impossible part is travelling in the sprawl with relatively short time, as limited by the road's speed limit. The real limiting factor most of the time is traffic, because of the space inefficiency of cars.

I made this point because I seem to recall a city simulation game despawn cars (literally physically impossible) to make car dependent designs "work".

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> you can reach enough of a city to consider it all the advantages of a city

With enough people driving downtown you lose most of the advantages, and it makes the lives of those who didn't choose this lifestyle worse.

Walking is probably the most efficient from a (public) health viewpoint. Given that the major problem in the West is lack of physical activity and excess calorie input.

Which is to say, the least efficient

Well you don't need a bike for walking, so that's gotta count for something (if efficiency is defined as total energy spent per distance)

Is taking an ebike really that efficient if its going to be stolen? I kid.. because I have one. But I take 3 locks with me when I need to leave it unattended...

I do worry about this some, but I also have my bikes insured including an e-cargo bike. Cheaper than most car insurance. Still would be a pain in the ass if my bike got stolen though.

In the Netherlands many insurance companies have stopped offering insurance for ebikes and electric cargo bikes, because the chance of theft is too high (approaching 90% in Amsterdam on certain types according the insurance companies).

I wonder how this ranking might change if we also took into account the energy required to produce the extra calories that humans need to consume in order to get around via these modes of transportation.

Like, you'd probably expend a lot of calories traveling 10 miles by unicycle, and over time maybe that would be more significant than the materials difference compared to cycling?

Of course, it depends a lot on the diet of the human in question.

Most humans on earth already eat way more than what they need. Exercising might actually make them eat less in the long run, because they'll lose weight and not eat so much anymore.

There's a secondary cost savings in reduced health care costs from the extra exercise. (May not apply in all countries, but does for the US/Europe).

At least part of what keeps people from switching to more eco-friendly transportation is the protection arms race: people buy bigger cars because they are safer for their occupants. This leads to more injuries because bigger cars do more damage. Which means people are more concerned about injuries and buy bigger cars.

This is one area where I am concerned about the impacts of electric vehicles. They weigh a lot more than ICE cars and might cause more significant injuries for pedestrians. There probably ought to be some sort of tax or fee on vehicles that scales by weight. However, that would favor ICE vehicles over EVs so it may not be popular among the people who might otherwise be interested in such things.

IANA automotive engineer, but I would assume that injuries from car-vs-pedestrian collisions are mostly due to impact velocity, and not due to momentum.

I wouldn’t be surprised if the higher-mass electric vehicles are more dangerous to other cars when involved in car-vs-car collisions, though.

Smaller cars are more likely to throw you up and over - still dangerous, but not as dangerous as a direct inelastic hit. Smaller cars have better visibility of pedestrians and so are more likely to see and thus avoid pedestrians.

If you take a direct hit with even a tiny car at faster than 30mph you are dead. However smaller cars make it somewhat less likely you take that direct hit.

Yeah — but when I hear people talking about how EVs are heavier, I assume that people are making a like-for-like model comparison.

In a similar body size, EVs tend to weigh more, due to all the extra battery.

IANA automotive engineer either. I'll quote national bureau of economic research:

> The probability of a fatality, conditional on a collision, is 0.19 percent -- or about one in five hundred. The authors find that being hit by a 1,000-pound heavier vehicle results in a 47 percent increase in the baseline probability of being killed in the accident...

https://www.nber.org/digest/nov11/vehicle-weight-and-automot....

I would be delighted to ride a zip line to work

Energy efficiency is not the only variable that matters. Walking to my grocery store would take almost two hours each way. Biking would take 30 minutes each direction. Driving is 14 minutes each way, and is the only feasible way I can get groceries when I have my kids in tow (which sometimes is a necessity).

Of course. If in the big picture we want fewer people to need to take a car for each trip, it would be a good idea to have towns and cities where grocery stores and houses are closer together.

And of course not everyone wants to live in such a place, but plenty of people would. And in the US this is fairly rare compared to many other parts of the world.

Who wouldn't want to live close to the grocery store? Here in Dublin I live in a house with gardens front and back, 5km from the center of the city, with a grassy park in front of my house (football field size), yet I can walk to 4 different supermarkets. The furthest is about 15m walk, the nearest is 10m. And I've got a few small convenience shops even closer (like, under 5m walk). This is what I call "perfect", and I don't understand why someone wouldn't want this.

Unfortunately they stopped building communities like this in the 1950s, but they sprawl for miles around Dublin, and I consider myself lucky to be able to live here.

I've visited cities in the Midwest of the US and found them to be like hell. Can't walk anywhere.

Oh I would definitely prefer it. I think a lot of people would. So many Americans haven't lived that life though that it can be hard to imagine.

It also helps if it's not raining, and when there are no slippery surface conditions.

How inefficient is it that your grocery store is 5 miles away? Everyone should have a grocery store within a 5 minute walk of where they live.

A very tiny number of people in the US live a 5 min walk from a grocery store.

Many people live within 5 miles of one, but usually in denser areas where 5 miles could easily take 30-60 min of travel.

>A very tiny number of people in the US live a 5 min walk from a grocery store.

That's exactly the problem. There needs to be more housing built near grocery stores, and more grocery stores built where the housing is, instead of 5 miles away.

Right, but in denser areas it's kind of crazy that more people aren't within 1-2 miles of a grocery store.

In my city, everyone I know lives within 1 mile of a grocery store, but they drive anyway. Many have kids and their groceries take up a lot of space, and they don't have the leisure time to spend on walking anyway.

So how does it work? How do you e.g. get your fresh bread in the morning? Are there some local community bakieries instead?

A small fraction of Americans shop daily for food. For the majority, it's a weekly (or even less frequent) occurrence.

And no, fresh bread is not really a thing, outside of a few urbanish settings. A healthy proportion of bakeries don't even sell bread - only pastries, cakes, etc.

Americans almost never buy fresh bread. We buy packaged bread with preservatives that lasts about a week (much longer if frozen or refrigerated).

Most of us don't go to the grocery store more than once or twice a week. When we do, it's often a big purchase that you can't carry back in your hands or on a small bike. You'd need something with more cargo space.

8km is about 20-35 minutes on a bike depending on infrastructure, I am sure it is zero minutes in many places due to lack of infrastructure. It is extremely cheap to build, and fast, look at Paris it is rapidly becoming a more bicycle friendly city, it is still carmagedon though.

When I grew up we went to a grocery store 5 miles away, even though the closest was only 2 blocks. Once in a while we walked to the close store, but it was so much more expensive than the farther away one that we just about paid for the entire cost of the car just on the grocery savings.

I can't control the prices of the local store, and so it is efficient to have the ability to choose other stores and thus force them to compete on price.

Of course, many people forget that there are folks living in villages / remote areas like you.

I’d never even consider living anywhere where it‘d take me 15 minutes to the grocery store no matter what mode of transport. How long is your commute? I have like ten grocery stores in fifteen minute cycling distance, the closest is two minutes away.

I work from home, so my commute is 0 minutes XD

tbf I prefer to measure human loss in QALYs in case a disease mostly kills old people. It's impossible to measure perfectly but it's not worse than "A death". We all die in the end.

Certainly in the Bay it's pretty easy to get by with no car at all - just rent or borrow one if you want to take a trip to Tahoe every once in a while. If you go deeper into the country though, there are many places where car ownership is nearly mandatory, especially for people who can't WFH.

EVs are pretty close to being able to replace ICE cars around here, but still can't match the range, cost, or longevity of an ICE vehicle. I could do 80%+ of my miles in an EV, but once or twice a year, we take a 1000 mile road trip that would be considerably more painful in an EV. If we're only going to own one car, it still needs to be ICE.

That said, I do own two cars. One of them is a 2001 Ford truck that is on its last legs. It's not very environmentally friendly to run, but given that I put so few miles on it per year, it's probably better than causing a new car to be produced, regardless of its technology.

Would I still be able to run a 2023 EV in 2044? Will the batteries last that long, with any sort of usable range?

> but once or twice a year, we take a 1000 mile road trip that would be considerably more painful in an EV. If we're only going to own one car, it still needs to be ICE.

You could just rent a car for those two trips like you suggested yourself in your first paragraph ;). Optimise for the most common scenario, not the least common one.

> Would I still be able to run a 2023 EV in 2044? Will the batteries last that long, with any sort of usable range?

Replacing the battery pack on an EV once every 15 years is certainly cheaper than all the maintenance that goes into an ICE in the same timeframe. Hopefully we can start recycling batteries properly before the current generation of EVs is up for battery replacements.

The cost to rent a car for a week is getting close to the cost of just owning a car. (very much it depends, if you only own new cars renting is cheaper, but most people own older cars which are much cheaper). Plus when you rent they worry about little scratches and such which limits what you can do on vacation.

I’m not sure what math you’re on, usually the metric is 1-2 months to match ownership.

I recently hired a small car for £20 a day. Not a special deal, that’s just the price. A week would make that £140. An old car would cost almost twice that in taxes. Then you have maintenance, insurance, MOT, and devaluation.

If you can use a small car. I have a family, so I need a larger car (minivan, but typically they give me a large SUV). $100/day. A used minivan amortized over years is pretty cheap.

> If you go deeper into the country though, there are many places where car ownership is nearly mandatory, especially for people who can't WFH.

This is true, but it's also worth noting that it's true because small and medium-sized cities systematically dismantled their public transportation systems between the 1920s and 1960s, replacing them with infrequent bus services.

One of the things I do when trying to understand how so many of our smaller cities became car hells is to Google "$CITY streetcars 20th century." We had the infrastructure and chose to remove it.

Yes, my city is one of those. Sadly it leads to a death spiral. The bus sucks, so nobody rides it, so the bus gets no money, so they cut routes, so the bus sucks more, so fewer people ride it.......

Yeah probably. Every EV comes with an 8+ year battery warranty, and it seems pretty rare to actually use it. No one I know has.

From anecdotes I've seen online, the only people who experience serious serious range degradation are atypical users (eg a taxi with 500k miles that exclusively uses fast charging) or owners of cars that don't have any thermal management for the battery (e.g. Nissan Leaf).

> a 4000 lb vehicle

Amateur numbers.

The F-150 Lightning is 6,500 lb (2,950 kg) and the Rivian trucks (R1T, R1S) are 7,000 lb (3,175 kg). The electric F-150 is 35% heavier than the ICE model.

Meanwhile:

https://news.ycombinator.com/item?id=37726539

not to get us too far off track, but unicycling is WAY less efficient than walking.

For those that have never tried it: it's like trying to go for a jog while maintaining a three-quarters-squat posture.

I’m disappointed they weren’t talking about electric unicycles…I have one of those, and it just feels like skiing. No real effort required.

Many aspects to the word "efficiency".

Space efficiency - how wide it takes to reach a certain throughput - train wins

Time efficiency - how much time it takes to get from point A to point B - barring traffic, car wins

Energy efficiency - how much energy it takes - bike wins

Your argument is just as strong without the subjective ranking of efficiency.

Majority of my time commuting the bike wins every time, mostly because I'm commuting at the same time as everyone else.

Good for you. Doesn't describe everyone else.

Not an option any more when you need to start dropping kids off at school first - not to mention the weather and safety.

There are tons of options for carrying kids on a bike. Made even easier when you add electric assist.

I can imagine parents not wanting to take the risk of being outside two-tonne metal boxes on the road with their children. Infrastructure matters a lot.

I drop my kids off at school on the way. They bike too. Started with a trail-a-bike, and now they are their own bikes and I bike with them to school on my way.

I bet you live in a different climate than me. ...and your kids are likely older. These factors matter dramatically.

> (5) Mass transit (can be public/private) transportation: Electric trains

This depends quite a lot on ridership. E.g. a typical MAX train in Portland, filled at perhaps 10% capacity aside from a few narrow time periods in the morning and evening, loses out on efficiency to a Honda Civic with four people. Trains are heavy even when they are empty.

But most cars are not filled with 4 people: quite often it's only one or two

And many don't drive a Honda civic: they are driving the biggest, heaviest car they can get their hands on

> We don't need

Let me stop you right there. We "don't need" most of the possessions you currently own, including the one you're using to browse HN. We don't live for mere subsistence.

People can decide for themselves what they want to give up to reduce their carbon footprint, and that doesn't necessarily have to be their vehicle.

If you're defining efficiency as energy required to travel a distance, then an electric bike that doesn't require effort from the rider is going to be way more efficient than walking or cycling.

That was one of the exercises I had when studying - calculate the energy intensity of various modes of transport. It turns out that if you calculate the whole energy requirements to get the extra food into someone's mouth that they'll want if they are walking or biking, then it's not much different to the amount of energy that would be used by just driving a car. Making food is energy-intensive, and the conversion efficiency into mechanical output by a working person is very low. In contrast, an electric motor and a battery can both be made extremely efficient.

Would you show your work? I am curious and a little bit skeptical.

A gallon of gasoline has about 31,000 kcal. In the US, a typical sedan gets about 30 miles per gallon.

Walking a mile at 150lb bodyweight burns about 100 kcal. (This is non linear though: walking longer distances will burn less per mile on average)

If we assume linearity, to walk an extra 30 miles in a day you'd need 3000 more kcal of food. What is the energy cost of growing and transporting 3000 kcal of food? Does it exceed 31,000 kcal?

This was 10-15 years ago, so I don't have my notes lying around. However, I do remember that it was based on the calorific efficiency of bread bought at a supermarket. Other foods may vary - for instance if you grow potatoes in your back garden then it's probably going to be a lot more efficient.

I can well believe that there is a 10:1 ratio between energy in and mechanical energy out of a human.

However my point wasn't that cars and humans are about the same. That's probably only true in the "same order of magnitude" sense. My point was that humans are way less efficient at propelling a bicycle than an electric motor is.