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I read this mostly as a semantic difference. Both supply and demand generally exist as curves and changing the position of the supply curve changes the positio

by slg 5y ago

I read this mostly as a semantic difference. Both supply and demand generally exist as curves and changing the position of the supply curve changes the position it intersects with the demand curve. The demand curve isn't actually changing. Whether we call that move from the first intersection to the second "induced demand" or "release of suppressed demand" doesn't really matter in my opinion. The concept is the same. Jevons Paradox is a little different in that it doesn't change how we traditionally model the supply curve (that is probably why the two graphs on that Wikipedia page only show the demand curve). But the end result is the same that we have now moved to a different spot on the demand curve.

AnthonyMouse 5y ago
Yes, it's all about moving to a different place on the demand curve. It's two things that regularly get missed with induced demand. The first is the assumption of infinite demand. If two lanes isn't enough, and you add a third and that isn't enough, by induction (pun intended) you wouldn't have enough even with infinity lanes. But in practice it will be finite and might only be four. The second is that you can "induce" demand by removing demand, and therefore reducing congestion and increasing demand. If your goal is to eliminate congestion then one way or another you have to satisfy the demand that exists without congestion.
- beerandt 5y ago
  Another blind spot is people using it as an reason/excuse for public transport. They somehow see a new lane as inducing demand, but not train tracks or a seat on a bus.
  - 9935c101ab17a66 5y ago
    If more train lines or more bus seats increases the number of people using public transit, that's an unequivocal victory and is in fact the whole point of public transit.
    - beerandt 5y ago
      Not if they go unused or underused, or otherwise end up being less efficient and/or more costly overall than the alternatives. Then it's worse of both worlds. Theoretical efficiency and real-world efficiency are different things. Public transit isn't inherently good by virtue of existing without real-world benefits. (To assume or believe it good without proof would be dogmatic faith, not science.) And those benefits gained need to be greater than any and all offsetting costs lost. There are far more real-world scenarios where busses and trains end up being far less efficient than driving and flying than vice-versa. The difference in logistical degrees of freedom between the two sets makes bus and rail far too reliant on ideal geographic and operating conditions. Yet it's always these few ideal scenarios that are the basis for most cost and efficiency comparisons & claims, and are what get presented as justification for building/implementing. And the countless public transport systems that never get the ridership or revenue that their pre-construction cost/benefit analysis or environmental impact statements predicted is proof that they rely on overly optimistic assumptions that rarely pan out.

by slg 5y ago

AnthonyMouse 5y ago

Yes, it's all about moving to a different place on the demand curve. It's two things that regularly get missed with induced demand. The first is the assumption of infinite demand. If two lanes isn't enough, and you add a third and that isn't enough, by induction (pun intended) you wouldn't have enough even with infinity lanes. But in practice it will be finite and might only be four. The second is that you can "induce" demand by removing demand, and therefore reducing congestion and increasing demand. If your goal is to eliminate congestion then one way or another you have to satisfy the demand that exists without congestion.

beerandt 5y ago
Another blind spot is people using it as an reason/excuse for public transport. They somehow see a new lane as inducing demand, but not train tracks or a seat on a bus.
- 9935c101ab17a66 5y ago
  If more train lines or more bus seats increases the number of people using public transit, that's an unequivocal victory and is in fact the whole point of public transit.
  - beerandt 5y ago
    Not if they go unused or underused, or otherwise end up being less efficient and/or more costly overall than the alternatives. Then it's worse of both worlds. Theoretical efficiency and real-world efficiency are different things. Public transit isn't inherently good by virtue of existing without real-world benefits. (To assume or believe it good without proof would be dogmatic faith, not science.) And those benefits gained need to be greater than any and all offsetting costs lost. There are far more real-world scenarios where busses and trains end up being far less efficient than driving and flying than vice-versa. The difference in logistical degrees of freedom between the two sets makes bus and rail far too reliant on ideal geographic and operating conditions. Yet it's always these few ideal scenarios that are the basis for most cost and efficiency comparisons & claims, and are what get presented as justification for building/implementing. And the countless public transport systems that never get the ridership or revenue that their pre-construction cost/benefit analysis or environmental impact statements predicted is proof that they rely on overly optimistic assumptions that rarely pan out.