5 ms·

I disagree with the author's premise that Induced demand is not a useful concept, as I think his "suppressed demand" alternative is a bit myopic > The demand i

I disagree with the author's premise that Induced demand is not a useful concept, as I think his "suppressed demand" alternative is a bit myopic > The demand is not really ‘induced’: it’s more true to say that it was always there – when the roads don’t exist to accommodate it you could call it ‘suppressed demand’. This has been debunked and rebuked to death. 1. The suppressed (latent would have been a better word for what he's claiming but i digress) demand is not for cars, it's for fast transportation 2. Some people will absolutely take trips they otherwise wouldn't when more throughput is available 3. Leisure driving is absolutely a thing When I think of "suppressed" demand, I think of economically useful demand that needs to exist. Perhaps that's my own bias on the semantics of these words, but if so that's just another reason why I think "induced" is more accurate-to-reality than "suppressed" or "latent" Also, > If we offer more subsidised social housing, more people tend to live in it – would we then say that demand for social housing has been ‘induced’? Yes, yes I would. The demand is for housing, and only a subset (which I would bet is minor) would prefer social housing over detached housing. However, social housing is much more economically efficient (similar to buses and trains and public transit in general), so of course the excess demand will fill up social housing when it comes available. Did the author get a proofreader or editor before posting this or is it just an independent blog post?

randomdata 3y ago
As commonly defined, latent demand and induced demand are effectively the same thing, albeit observed at different points in time. With respect to highways, latent demand describes the potential demand before the improvements are made. Induced demand describes the shift from potential to actual demand after the improvements have been made.
- ryathal 3y ago
  While they may measure the same thing the connotation is different and often only applied to cars like the article says. We don't say more low-income housing created demand for low-income people. We don't say building a school created demand for children. Flipping cause and effect for expansion of roads is wrong.
  - randomdata 3y ago
    > the connotation is different Of course. One speaks to the potential demand before something changes, and one speaks to the potential demand converting to actual demand after something changed. We went over this already. > We don't say more low-income housing created demand for low-income people. We don't say building a school created demand for children. Of course. More low-income housing does not create demand for low-income people. Building a school does not create demand for children. And expanding a road doesn't create demand for driving. It merely induces it, hence why we call it induced demand, not created demand. > Flipping cause and effect for expansion of roads is wrong. There's really nothing to flip. Whether you use latent demand or induced demand just depends on the point in time you are referring to. In the case of roads, one applies pre-construction, one applies post-construction. It's not like anyone thinks that if we turn the countryside dirt road that sees little more than the occasional tractor into a multi-lane highway that the cars are magically going to show up in droves. It is well understood that we only expand the roads that actually show strong indication that more use will occur when expanded. Hence latent and, later, induced demand – never created demand.
dataflow 3y ago
> When I think of "suppressed" demand, I think of economically useful demand that needs to exist. Are you certain this isn't just your own personal view? Just casually double-checking on the internet, I don't see "economically useful" as part of any definition. It seems to be all about "willingness and ability to pay" for a good or service, as useless as it may be.
- bluGill 3y ago
  It is economically useful in the subjective eyes of the person who wants to do that. Since it isn't an objective measurement we don't talk about it in economics, but willingness and ability to pay are proxies for it.
schiffern 3y ago
>When I think of "suppressed" demand, I think of economically useful demand that needs to exist. Because cars have so many unpriced externalities (smog-forming pollution, oil spills, noise-induced stress, tire microplastic dust, undercompensation for pedestrian deaths, etc), often the demand is not actually "economically useful" in the final analysis. That's the elephant in the room. Since we apparently won't accept carbon/congestion pricing, then (as a fallback) any rational policymaker should want to suppress car demand. Paradoxically this improves economic efficiency, by helping counteract the perverse Externalization Subsidy. EDIT: Policymakers can sometimes go too far, of course, or not far enough. Policy requires tuning. That's the downside of using central planning instead of Economist's Own(TM) straight sin tax, but again apparently we won't do that.
- ars 3y ago
  You are vastly overinflating the negative parts of the a car, and undercounting the positive. There are figures for the negative externalities of cars, they are not hard to find. They don't even come close to the economic activity made possible by cars. A policymaker that suppresses car demand will kill his city. And we are going to get front row seats to see if I'm right: Manhattan congestion pricing is coming, so we'll find out. I predict it's gone within 3 years. I also predict the New Jersey roads that go around Manhattan are going to get slammed as people who just need to go through Manhattan to the rest of New York avoid it and head North to go around it. This will add enormous congestion, and the net result will be far worse traffic everywhere except central Manhattan.
  - opportune 3y ago
    Worse traffic everywhere except Manhattan is the point. Whether it’s so bad that the policy is net-negative is an open question. Over a long period of time I think traffic patterns will shift as society structures itself away from NJ-LI commutes (people moving to the area or accepting new jobs avoid that route, etc)
    - ars 3y ago
      So it's great if you live in Manhattan and never leave it. It will be worse for you in all other cases. But since I assume people in Manhattan also travel I suspect it will be a net negative for everyone.
deleted 3y ago
[deleted]
throwaway99989 3y ago
> 1. The suppressed demand is not for cars, it's for fast transportation This is moot. Yes, people demand fast transportation. Fast transportation in practice means cars. In other words, people demand cars.
- mitthrowaway2 3y ago
  ... or railways? Just got back from Tokyo and it didn't seem like anybody was demanding cars. North America seems to have a tremendous, gargantuan shortage of passenger rail, especially in comparison to how much land we dedicate to freeways.
  - adrianN 3y ago
    To be fair, traffic in Tokyo is still pretty bad. However the city would definitely collapse if it weren’t for public transport
  - deleted 3y ago
    [deleted]
  - defrost 3y ago
    North America has had 50 years of focused effort from Koch's Americans for Prosperity and other similarly themed lobby groups spreading the word that public transport bad, individual FreeDumb coal rolling good. You'd almost think they profit from that message somehow. Luckily for transit enthusiasts, the Kochs have not always been successful, even in sprawling cities with a sizable Republican base. Phoenix, Arizona[1], successfully expanded its light rail system in the face of opposition from the organization’s state branch. [1] https://www.azcentral.com/story/news/local/phoenix/2015/08/25/phoenix-elections-transit-results-prop104/32283455/ https://www.azcentral.com/story/news/local/phoenix/2015/08/2... https://www.theguardian.com/us-news/2019/aug/26/koch-activists-phoenix-ban-light-rail https://www.theguardian.com/us-news/2019/aug/26/koch-activis... https://grist.org/article/the-koch-brothers-hate-public-transit-but-they-cant-always-stop-projects-in-their-tracks/ https://grist.org/article/the-koch-brothers-hate-public-tran... https://scholarscompass.vcu.edu/uresposters/290/ https://scholarscompass.vcu.edu/uresposters/290/
scythe 3y ago
>When I think of "suppressed" demand, I think of economically useful demand that needs to exist. There are cases where this is true: https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=3fdc4c4014ec3e1ef73c1fbb25d4bc901aeafbb1 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&d... When networks are deficient, roads can lead to large benefits: https://sites.bu.edu/neudc/files/2014/10/paper_243.pdf https://sites.bu.edu/neudc/files/2014/10/paper_243.pdf As networks reach sufficiency, the impact on economic activity decreases: https://www.sciencedirect.com/science/article/pii/S0967070X1530024X https://www.sciencedirect.com/science/article/pii/S0967070X1... This is not something that can be accurately shoved into an all good or all bad perspective. Whether roads are positive for economic development is a necessarily quantitative question. >only a subset (which I would bet is minor) would prefer social housing over detached housing. The author is speaking from a British perspective, and there "social housing" means government-subsidized housing. It is not a form factor and cannot meaningfully be placed in opposition to detached houses.
- hughesjj 3y ago
  Ah, my mistake about the regional difference in terminology. Still, I'd continue to argue that the demands are for fast (+safe+comfortable) transit and housing in general, not automobiles and government subsidized housing in general (I'm sure pretty much any mechanism of affordable housing is in high demand in the UK) Since we're on hacker news, 'the design (need) calls for fast transportation. Claiming we need to build to support more cars is enforcing an implementation without actually considering other design alternatives that will satisfy the need'
ars 3y ago
> When I think of "suppressed" demand, I think of economically useful demand that needs to exist. It's really not for you to decide what is a "useful" trip for people. That leads nowhere good. I mean, how far will you take idea that you decide what's "worth it" for people to do? > This has been debunked and rebuked to death. Your premise is not supported by your argument, the opposite in fact. If people want to take a trip, but don't because it's too slow, that is indeed the definition of "suppressed". > demand is not for cars, it's for fast transportation Those are currently synonyms. After you have created a new world you can redefine things, but in arguments like these you have to use the current meaning of things. In every place that I've used public transportation, which is not just in the US, public transport takes twice as long as a car. I even went online to Google Maps and picked random addresses in London - supposedly the public transport capital of the Western World, and the law holds: Cars are twice as fast.
- xp84 3y ago
  > Cars are twice as fast. With our current infrastructure, yes, but that's because of how we chose to design things. If we built 10 residential towers within a 7 minute walk of a rapid transit station, and run trains every 3 minutes at peak times, you bet your bottom dollar transit will destroy a car commute for every resident of those towers. I'm thinking of places like say, Daly City and Colma BART, for instance, whose locations would be great car commutes at 2AM, but 5-6 stops on a train beat rush hour car traffic every day -- IF the first and last mile doesn't ruin it! Now, I'm 100% not saying "everyone ought to be forced to live in high-rises over a train station" -- but I would absolutely bet you that if such residences were built with a variety of human needs in mind (for instance, plenty of them with 3-4 bedrooms for larger families instead of the usual urban mix of 1-2 bedroom units), people who presently drive an hour each way to work "downtown" would be tripping over themselves to buy them because they'd get to work faster and get to browse Insta en route as well. Instead though, for the most part, such things basically don't exist. For instance, the sites I'm describing in the Bay Area are surrounded by large tracts of SFH. (Or in the case of Colma, 1/4 that, 1/4 car-centric malls, and 1/2 cemeteries. Genius location for a transit station, guys.) Anyway sorry for being long-winded, just all I'm saying is cars are twice as fast because we dedicate enormously more space and subsidies to them, and we don't make much effort to design any part of our cities or suburbs in a way that any other type of transit could really work. It's a conscious choice we have made, and a dumb one.
ipdashc 3y ago
> Leisure driving is absolutely a thing This seems kind of an odd one to throw in. Leisure driving is fun, but you generally do it on empty country roads, no? Or in general when the roads are clear. Nobody goes to stop-and-go down a congested interstate or suburban stroad for leisure.
- hughesjj 3y ago
  I'm throwing it in for the sticklers as an example of something which truly is induced. They wouldn't be driving for leisure in those geographic locations without roads with low traffic existing. The demand requires a certain low utilization for this cohort. Also, as someone who lived next to the convention center (and thus i5) in Seattle for ~5 years, there are absolutely people who will drive down i5 for leisure driving. Lots of people racing or otherwise speeding. Hell I would do the same (minus speeding and reckless driving) along 76 and the Schuylkill when I lived on the east coast. Heck some of the biggest opposition in Seattle to tearing down the viaduct (damaged by the nisqually, unlikely to survive another earthquake) was from people who 'would miss the view/drive coming into the city's, and would wax poetic about their literal Sunday drives down such, especially right at sunset.

randomdata 3y ago

As commonly defined, latent demand and induced demand are effectively the same thing, albeit observed at different points in time. With respect to highways, latent demand describes the potential demand before the improvements are made. Induced demand describes the shift from potential to actual demand after the improvements have been made.

ryathal 3y ago
While they may measure the same thing the connotation is different and often only applied to cars like the article says. We don't say more low-income housing created demand for low-income people. We don't say building a school created demand for children. Flipping cause and effect for expansion of roads is wrong.
- randomdata 3y ago
  > the connotation is different Of course. One speaks to the potential demand before something changes, and one speaks to the potential demand converting to actual demand after something changed. We went over this already. > We don't say more low-income housing created demand for low-income people. We don't say building a school created demand for children. Of course. More low-income housing does not create demand for low-income people. Building a school does not create demand for children. And expanding a road doesn't create demand for driving. It merely induces it, hence why we call it induced demand, not created demand. > Flipping cause and effect for expansion of roads is wrong. There's really nothing to flip. Whether you use latent demand or induced demand just depends on the point in time you are referring to. In the case of roads, one applies pre-construction, one applies post-construction. It's not like anyone thinks that if we turn the countryside dirt road that sees little more than the occasional tractor into a multi-lane highway that the cars are magically going to show up in droves. It is well understood that we only expand the roads that actually show strong indication that more use will occur when expanded. Hence latent and, later, induced demand – never created demand.

dataflow 3y ago

> When I think of "suppressed" demand, I think of economically useful demand that needs to exist. Are you certain this isn't just your own personal view? Just casually double-checking on the internet, I don't see "economically useful" as part of any definition. It seems to be all about "willingness and ability to pay" for a good or service, as useless as it may be.

bluGill 3y ago
It is economically useful in the subjective eyes of the person who wants to do that. Since it isn't an objective measurement we don't talk about it in economics, but willingness and ability to pay are proxies for it.

schiffern 3y ago

>When I think of "suppressed" demand, I think of economically useful demand that needs to exist. Because cars have so many unpriced externalities (smog-forming pollution, oil spills, noise-induced stress, tire microplastic dust, undercompensation for pedestrian deaths, etc), often the demand is not actually "economically useful" in the final analysis. That's the elephant in the room. Since we apparently won't accept carbon/congestion pricing, then (as a fallback) any rational policymaker should want to suppress car demand. Paradoxically this improves economic efficiency, by helping counteract the perverse Externalization Subsidy. EDIT: Policymakers can sometimes go too far, of course, or not far enough. Policy requires tuning. That's the downside of using central planning instead of Economist's Own(TM) straight sin tax, but again apparently we won't do that.

ars 3y ago
You are vastly overinflating the negative parts of the a car, and undercounting the positive. There are figures for the negative externalities of cars, they are not hard to find. They don't even come close to the economic activity made possible by cars. A policymaker that suppresses car demand will kill his city. And we are going to get front row seats to see if I'm right: Manhattan congestion pricing is coming, so we'll find out. I predict it's gone within 3 years. I also predict the New Jersey roads that go around Manhattan are going to get slammed as people who just need to go through Manhattan to the rest of New York avoid it and head North to go around it. This will add enormous congestion, and the net result will be far worse traffic everywhere except central Manhattan.
- opportune 3y ago
  Worse traffic everywhere except Manhattan is the point. Whether it’s so bad that the policy is net-negative is an open question. Over a long period of time I think traffic patterns will shift as society structures itself away from NJ-LI commutes (people moving to the area or accepting new jobs avoid that route, etc)
  - ars 3y ago
    So it's great if you live in Manhattan and never leave it. It will be worse for you in all other cases. But since I assume people in Manhattan also travel I suspect it will be a net negative for everyone.

deleted 3y ago

[deleted]

throwaway99989 3y ago

> 1. The suppressed demand is not for cars, it's for fast transportation This is moot. Yes, people demand fast transportation. Fast transportation in practice means cars. In other words, people demand cars.

mitthrowaway2 3y ago
... or railways? Just got back from Tokyo and it didn't seem like anybody was demanding cars. North America seems to have a tremendous, gargantuan shortage of passenger rail, especially in comparison to how much land we dedicate to freeways.
- adrianN 3y ago
  To be fair, traffic in Tokyo is still pretty bad. However the city would definitely collapse if it weren’t for public transport
- deleted 3y ago
  [deleted]
- defrost 3y ago
  North America has had 50 years of focused effort from Koch's Americans for Prosperity and other similarly themed lobby groups spreading the word that public transport bad, individual FreeDumb coal rolling good. You'd almost think they profit from that message somehow. Luckily for transit enthusiasts, the Kochs have not always been successful, even in sprawling cities with a sizable Republican base. Phoenix, Arizona[1], successfully expanded its light rail system in the face of opposition from the organization’s state branch. [1] https://www.azcentral.com/story/news/local/phoenix/2015/08/25/phoenix-elections-transit-results-prop104/32283455/ https://www.azcentral.com/story/news/local/phoenix/2015/08/2... https://www.theguardian.com/us-news/2019/aug/26/koch-activists-phoenix-ban-light-rail https://www.theguardian.com/us-news/2019/aug/26/koch-activis... https://grist.org/article/the-koch-brothers-hate-public-transit-but-they-cant-always-stop-projects-in-their-tracks/ https://grist.org/article/the-koch-brothers-hate-public-tran... https://scholarscompass.vcu.edu/uresposters/290/ https://scholarscompass.vcu.edu/uresposters/290/

scythe 3y ago

>When I think of "suppressed" demand, I think of economically useful demand that needs to exist. There are cases where this is true: https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=3fdc4c4014ec3e1ef73c1fbb25d4bc901aeafbb1 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&d... When networks are deficient, roads can lead to large benefits: https://sites.bu.edu/neudc/files/2014/10/paper_243.pdf https://sites.bu.edu/neudc/files/2014/10/paper_243.pdf As networks reach sufficiency, the impact on economic activity decreases: https://www.sciencedirect.com/science/article/pii/S0967070X1530024X https://www.sciencedirect.com/science/article/pii/S0967070X1... This is not something that can be accurately shoved into an all good or all bad perspective. Whether roads are positive for economic development is a necessarily quantitative question. >only a subset (which I would bet is minor) would prefer social housing over detached housing. The author is speaking from a British perspective, and there "social housing" means government-subsidized housing. It is not a form factor and cannot meaningfully be placed in opposition to detached houses.

hughesjj 3y ago
Ah, my mistake about the regional difference in terminology. Still, I'd continue to argue that the demands are for fast (+safe+comfortable) transit and housing in general, not automobiles and government subsidized housing in general (I'm sure pretty much any mechanism of affordable housing is in high demand in the UK) Since we're on hacker news, 'the design (need) calls for fast transportation. Claiming we need to build to support more cars is enforcing an implementation without actually considering other design alternatives that will satisfy the need'

ars 3y ago

> When I think of "suppressed" demand, I think of economically useful demand that needs to exist. It's really not for you to decide what is a "useful" trip for people. That leads nowhere good. I mean, how far will you take idea that you decide what's "worth it" for people to do? > This has been debunked and rebuked to death. Your premise is not supported by your argument, the opposite in fact. If people want to take a trip, but don't because it's too slow, that is indeed the definition of "suppressed". > demand is not for cars, it's for fast transportation Those are currently synonyms. After you have created a new world you can redefine things, but in arguments like these you have to use the current meaning of things. In every place that I've used public transportation, which is not just in the US, public transport takes twice as long as a car. I even went online to Google Maps and picked random addresses in London - supposedly the public transport capital of the Western World, and the law holds: Cars are twice as fast.

xp84 3y ago
> Cars are twice as fast. With our current infrastructure, yes, but that's because of how we chose to design things. If we built 10 residential towers within a 7 minute walk of a rapid transit station, and run trains every 3 minutes at peak times, you bet your bottom dollar transit will destroy a car commute for every resident of those towers. I'm thinking of places like say, Daly City and Colma BART, for instance, whose locations would be great car commutes at 2AM, but 5-6 stops on a train beat rush hour car traffic every day -- IF the first and last mile doesn't ruin it! Now, I'm 100% not saying "everyone ought to be forced to live in high-rises over a train station" -- but I would absolutely bet you that if such residences were built with a variety of human needs in mind (for instance, plenty of them with 3-4 bedrooms for larger families instead of the usual urban mix of 1-2 bedroom units), people who presently drive an hour each way to work "downtown" would be tripping over themselves to buy them because they'd get to work faster and get to browse Insta en route as well. Instead though, for the most part, such things basically don't exist. For instance, the sites I'm describing in the Bay Area are surrounded by large tracts of SFH. (Or in the case of Colma, 1/4 that, 1/4 car-centric malls, and 1/2 cemeteries. Genius location for a transit station, guys.) Anyway sorry for being long-winded, just all I'm saying is cars are twice as fast because we dedicate enormously more space and subsidies to them, and we don't make much effort to design any part of our cities or suburbs in a way that any other type of transit could really work. It's a conscious choice we have made, and a dumb one.

ipdashc 3y ago

> Leisure driving is absolutely a thing This seems kind of an odd one to throw in. Leisure driving is fun, but you generally do it on empty country roads, no? Or in general when the roads are clear. Nobody goes to stop-and-go down a congested interstate or suburban stroad for leisure.

hughesjj 3y ago
I'm throwing it in for the sticklers as an example of something which truly is induced. They wouldn't be driving for leisure in those geographic locations without roads with low traffic existing. The demand requires a certain low utilization for this cohort. Also, as someone who lived next to the convention center (and thus i5) in Seattle for ~5 years, there are absolutely people who will drive down i5 for leisure driving. Lots of people racing or otherwise speeding. Hell I would do the same (minus speeding and reckless driving) along 76 and the Schuylkill when I lived on the east coast. Heck some of the biggest opposition in Seattle to tearing down the viaduct (damaged by the nisqually, unlikely to survive another earthquake) was from people who 'would miss the view/drive coming into the city's, and would wax poetic about their literal Sunday drives down such, especially right at sunset.