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Cunninghams_right t1_iyas3qt wrote

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id4thereddit t1_iyasnyt wrote

efficiency is using the least amount of energy to achieve the desired result. There is no hard value, but it is obviously not the most efficient means we have available to us for transportation.

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Cunninghams_right t1_iyaxvvh wrote

Well what is an acceptable level of efficiency? There are lots of systems that aren't perfectly efficient. Every Metro or light rail train or bus has different efficiency.

Like, is the St Louis light rail acceptably efficient? What about the Washington DC metro? Are either of these two inefficient?

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id4thereddit t1_iyayxjm wrote

I think we aim to do the best we can do. There is no end goal, just do our best.

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Cunninghams_right t1_iyb8bh9 wrote

I don't understand the comment, though. are you in opposition to their concept because it's EVs or in favor of it because it's EVs?

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id4thereddit t1_iyb8tai wrote

what is EVs?

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Cunninghams_right t1_iybchv8 wrote

ohh, sorry. I spend to much time in the "EV" subreddit. EV meaning battery-electric cars/trucks/vans. I should have been clearer. sometimes you get used to a shorthand or jargon and forget that others may not use the term that way.

let me rephrase: I don't understand the comment because it seemed like you're saying it's transportation that isn't energy-efficient, but it's certainly more energy efficient than some things by virtue of being battery-electric with regenerative braking, etc. thus, I was trying to figure out how you draw the line for acceptably efficient. like, diesel buses are not very efficient at all, so do you think we should we use buses or not? or maybe only in high ridership routes? what about people car-pooling in gasoline cars?

I'm just trying to get a gauge on what you mean.

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id4thereddit t1_iycglfn wrote

Individual transportation.

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Put it this way - if you were designing the transportation network for a planet of 8 billion from scratch, would you choose to assign each individual a 1.5M * 4M 2 tonne vehicle which will need to be stored when not in use nearby to the individual where ever they travel, which travels at a dangerous speed in close proximity to peoples homes by low skilled and often tired and distracted operators?

Cars evolved from a different time with different needs in a different world. It just does not make sense for the world we live in today.

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Cunninghams_right t1_iydykwe wrote

>Put it this way - if you were designing the transportation network for a planet of 8 billion from scratch, would you choose to assign each individual a 1.5M * 4M 2 tonne vehicle which will need to be stored when not in use nearby to the individual where ever they travel, which travels at a dangerous speed in close proximity to peoples homes by low skilled and often tired and distracted operators?

no, but there is a point where it is acceptable.

like, how about 2 people carpooled per vehicle? what about 4? what about 10?
what if the vehicle didn't need to be parked at your house but could come pick you up? what about Diesel buses vs Battery-electric buses?

like, regular city Diesel buses are just OK in energy efficiency. are they acceptable efficiency or should they not be run?

I'm trying to get an idea of what you (and anyone else who might like to chime in) think is acceptable efficiency and should be built vs unacceptable efficiency and should not be built.

I have my own thoughts on the subject, but I like to ask others so that I can not live in my own bubble where I think my values are the "right" values. I do transit advocacy and want to avoid "losing touch" with what a typical person thinks about the subject.

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id4thereddit t1_iye10tm wrote

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I'm not going to be able to give you any specific figures, too much context is needed - there are so many factors to be considered. The need and desire for people to be able to travel freely has to be balanced with the impact that the transportation method has - in terms of space required, energy needed, environmental impacts, infrastructure requirements etc.

There are plenty of parts in the world in which small vehicles can be justified - an Australian sheep farmer can make good use of a land rover for example. But for most modern city based lives any sort of private transportation quickly becomes prohibitive.

It is a large problem that would take a lot of joint up thinking to solve, involving city design, how and were we work etc.

I know a lot of people feel passionately attached to their vehicles and it represents independence and freedom for many people, but it is just not viable on a large scale.

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Cunninghams_right t1_iyeamvv wrote

wasn't really expecting exact figures.

but when talking about a city like Las Vegas, we can make decisions about different modes. like, what ridership level are buses ok? what ridership level are light rail lines ok? the energy efficiency of a tram may be lower than the energy efficiency of an elevated rail line but above a bus. but there is obviously a ridership factor, so 1 person on a tram is obviously more energy than 1 person in a car.

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id4thereddit t1_iyebo8c wrote

Well it is two different things - public transport such as trams and buses is different than privately owned vehicles. We need to be pushing people away from private ownership and investing into better public transportation. How exactly this is done I would leave to people like you.

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Cunninghams_right t1_iyf63ok wrote

I don't want to lean too much on a single example, but I'm having a hard time being clear without doing so.

example: IF self driving cars are available (like in Phoenix but even more plentiful), people could use them instead of private vehicles. if they are battery-electric, they would have ok energy consumption. so what if the self-driving EV had space for more people, like a mini-bus or van-like vehicle? well, at some point there are a number of passengers where an EV van/car/mini-bus becomes more efficient than a diesel bus, and there is a point where it is more efficient than a tram, and a point where it is more efficient than a metro.

in such a scenario, would cars or vans be acceptable? like, say you had 4 people in a single EV car, dividing the energy consumption 4 ways.

can we say "take the average efficiency of decent quality bus line, and any number of passengers per EV that gives that efficiency or better, that should be pursued". or should we have a higher bar than the average bus? like maybe the average light rail line or average tram?

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id4thereddit t1_iyf6nq1 wrote

So your question is could an efficient transportation system be designed around individual pods transporting through a dedicated network? I don't know, it doesn't sound like the most efficient to me.

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Cunninghams_right t1_iyfc0d4 wrote

no, I'm wondering if you had an electric van/bus service driving on regular streets (run by the transit agency or a private company), what efficiency level would be acceptable? say the EV van/bus could be as energy efficient as a typical bus at X number of passengers and as efficient as a typical light rail at Y number of passenger, should the service be used in a scenario where it will average X through the day of operation, or should the service only be implemented in places where it can average Y throughout the day?

I ask because we may get to a point in the coming years where buses can become autonomous and thus the size can be varied by cities (without having to worry about the driver cost), so that more frequent but less efficient buses/vans can be used for a route, or less frequent but more efficient buses/vans can be used.

to give another scenario:

you have two bus/van services

  1. arrives every 5 minutes, averages 5 passengers per vehicle
  2. arrives every 10 minutes, averages 10 passengers per vehicle.

obviously the 2nd option uses half as much energy per passenger moved, but the difference between 5min and 10min headways can be a big deciding factor in whether or not people ride transit. so 5min headway may get more people to stop driving their cars and take the bus instead. so maybe the scenario changes to:

  1. arrives every 5min, averages 8 passengers per vehicle
  2. arrives every 10min, averages 10 passengers per vehicle

now, the 1st option is still less energy-efficient per passenger, but it is stopping people from driving their own cars, which has benefits in terms of energy consumption bus also in other indirect ways like pollution, traffic noise, parking that could be turned into green-space or bike lanes, etc.

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id4thereddit t1_iyfcz1u wrote

I have completely lost interest in this conversation. go build your dream ev power city man, your passion outshines mine.

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