8 ms·

I thought the current thinking was that building more roads means that there will be more roads to use, and therefore more cars on the road. https://en.wikiped

by adamjc 10y ago

I thought the current thinking was that building more roads means that there will be more roads to use, and therefore more cars on the road. https://en.wikipedia.org/wiki/Induced_demand https://en.wikipedia.org/wiki/Induced_demand

kavok 10y ago
A tunnel doesn't have to specifically be for cars. Could run busses, trains, etc.. More electric cars on the road though wouldn't output more pollution around the road.
- tgb 10y ago
  Electric cars are a good match for tunnels: ventilating the tunnel enough for a whole lot of combustion engines to use is a real cost.
  - intrasight 10y ago
    And if the tunnel was limited to electric cars (likely), then that would boost Tesla.
Fricken 10y ago
That's the good thinking, but because it isn't intuitive it often gets kicked to the curb by bad thinking. More roads = less traffic, right? right? No? One could also use tunnels to build subways and presumably Hyperloops. I wonder, though, about why big infrastructure projects so horrendously expensive, in America in particular. There are developers, planners, consultants, politicians, unions, contractors, sub contractors, sub-sub contractors, and they're all out for all they can get. There are lawyers every step of the way. Nobody communicates well. Small hang-ups at the wrong place send the entire operation grinding to a halt. Can this be fixed? Is a big dumb tunnel digging operation the point of entry for infrastructure construction disruption in America? That would be nice. We're good at moving the bits around. We suck at atoms. Or is Musk setting himself up to be the next Robert Moses? Someone with the capability to move mountains, but not terribly discriminating about whether or not a given mountain should be moved. Musk doesn't talk like someone who's ever had a discussion with an Urban planner about the real reasons as to why our transportation problems are problems.
- nradov 10y ago
  US infrastructure construction costs are among the highest in the world. There appear to be multiple root causes including: extensive legal protections for private property owners, environment reviews and lawsuits, need to work across multiple government boundaries, labor laws, union work rules. https://www.bloomberg.com/view/articles/2016-04-08/why-u-s-infrastructure-costs-so-much https://www.bloomberg.com/view/articles/2016-04-08/why-u-s-i... http://www.citylab.com/work/2014/04/7-reasons-us-infrastructure-projects-cost-way-more-they-should/8799/ http://www.citylab.com/work/2014/04/7-reasons-us-infrastruct...
mwill 10y ago
Perhaps not a problem for Musk who also builds cars.
TulliusCicero 10y ago
Presumably the tunnels could also be used for transit, or maybe even walking/biking in some cases.
AYBABTME 10y ago
Tunnels will be required on Mars to shield from radiation. Getting a head start on the technology while on Earth only makes sense. Pretty much everything he plans is in perspective of having a dual use: will it be needed on Mars - SpaceX's true goal? I hate to say the word but, it's all about synergies.
RichardHeart 10y ago
If you move into a bigger house, your hallways will not fill up with more traffic. Currently humans are required at least 1 per car. Thus the housing and employment of those humans is more of a limiting factor on road demand, or perhaps car ownership or desire to drive somewhere, more so than availability of roads.
- syberspace 10y ago
  Your hallways may not fill up with people, but all your new closets, cupboards, wardrobes, drawers and whatnot will fill up with "stuff"
- ericd 10y ago
  If roads are clearer, then people tend to move farther from work, which increases the number of cars on the road at any given time. Then the roads clog up again. Increased highway construction has been enabling people to move farther and farther out into exurbs (which people think will be nice places to live, and cheaper, but that turn out create rather shabby quality of life compared to walkable cities).
  - Turing_Machine 10y ago
    "(which people think will be nice places to live, and cheaper, but that turn out create rather shabby quality of life compared to walkable cities)." "Shabby quality of life" by whose standards? The people who actually live there? I think not. If life in the suburbs actually sucked, people simply wouldn't stay there. It's not like they're given a one-way exit visa when they leave the city. They could move back any time they wanted. But, as a group, they never do. The reason they don't is because they find the amenities found in the suburbs (in specific, safety, cleanliness, room for their possessions, privacy, and better schools) preferable to those found in the cities. "Preferable" here means preferable by their standards, which are not the same as those of a single 22 year old programmer, or a single 30-something art connoisseur, or...
jessriedel 10y ago
Induced demand often happens, but certainly not always. It just depends on latent demand and network effects. More importantly, the appearance of induced demand is not a general argument against building roads! People get value out of getting to places. If we build road B intending to relieve congestion on road A, but road A stays just as congested, we nevertheless have enabled people to get places with road B that they would not otherwise have been able to reach. That increases utility. All of this applies to mass transit as well. The BART is currently at capacity during rush hour; if a parallel transit line was built, this would probably fill up with people without reducing congestion on BART, but it would still be creating value!
- elbigbad 10y ago
  Do you happen to have any examples of where induced demand has not happened? My understanding is that it is pretty much guaranteed, especially in larger cities. I think New York's bridges and tunnels are the canonical examples of this. I say pretty much because I assume there must be cases where it didn't happen, but I am unaware of them.
  - tgb 10y ago
    Maybe induced demand has always happened, in the sense of demand increasing when the product is more available. But it's plenty common for the amount that demand increases to be less than the amount of extra capacity available. Furthermore, is induced demand that bad? If you double the capacity and it again gets filled to the point of gridlock, well then at least twice as many people are now able to be in gridlock, which they apparently prefer to the alternatives.
    - mnw21cam 10y ago
      The example of when induced demand is bad is when it causes increased pollution. In many parts of the world, there is a deliberate movement towards avoiding building too many roads, in order to decrease road use and therefore pollution levels. However, a car sitting in traffic will produce much more pollution per mile than one travelling at 70mph on a clear road, so the thinking behind this may be flawed.
mason240 10y ago
The idea that we shouldn't build infrastructure because it will get used is one of the more silly talking points out there right now.
- Nav_Panel 10y ago
  Infrastructure projects should respond to the density and context of the neighborhood. Don't build a low-throughput highway between high density Manhattan and high density western Queens or it'll immediately become congested. Build a train instead. A bias toward highways in cities, which are inherently low throughput, has been the norm and also the problem over the last 80 years of urban infrastructure projects.
foobarrio 10y ago
Then why build roads at all? If N + 1 means more traffic than surely N - 1 means less? So 0 roads, no traffic! Seriously though isn't this a related rates problem? Adding roads adds capacity and also induces demand. Are the two in lockstep? Can the capacity added be greater than the demand induced?
- paulddraper 10y ago
  Not only that, but the more hyperloops we have, the more overburdened they will be. </s>
angry_napkin 10y ago
If you know 285 has an extra lane now, you'll go ahead and run that errand at a certain time that perhaps you wouldn't have otherwise. Fascinating stuff.
oftenwrong 10y ago
If a restaurant started giving out free food, you wouldn't be surprised when more people than usual went to eat there. Induced demand only happens when the road is underpriced. Any road can be made immune to induced demand by tolling at a price that reflects demand. Too much traffic? Raise the price. Looking a bit empty? Lower the price. Car dependence is only common in the US because drivers do not pay the true cost of driving. Many people could not afford to drive if they had to pay market price to use roads and parking. By disconnecting the cost of transportation from its use, we have evolved a society that is overly dependent on transportation, and that is overly sensitive to increases in transportation costs. This applies to all modes - not just cars.
Tiktaalik 10y ago
If Musk had talked with any expert in transportation at all he'd know that building a tunnel highway won't solve traffic problems in the long term. Either: A) He hasn't talked with any experts at all. B) He doesn't believe the experts. or C) He doesn't think inducing demand is a problem because he owns a car company. None of these possibilities are very good looks.
- jldugger 10y ago
  > C) He doesn't think inducing demand is a problem because he owns a car company. Just think how bad the smog would be on a car tunnel. Unless they limit it to zero emission vehicles....
paulddraper 10y ago
In economics terms, demand is a relationship between price and quantity demanded. Increasing the supply doesn't affect demand; it just changes the realized price and quantity to another place in the same demand relationship.
artumi-richard 10y ago
There has to be a ceiling to how much demand can be induced.
- marssaxman 10y ago
  One could view the US Interstate Highway System and its legacy of suburban sprawl as a massive, decades-long effort to reach that ceiling, but we don't appear to have run out of headroom yet.
tunesmith 10y ago
Induced demand is one of those things that always struck me as an abused concept. Yes, it happens, but it's impossible for it to be always true. New roads will attract more traffic, but only up to a point. There exist roads in the United States that aren't experiencing traffic jams at rush hour. If Induced Demand were a law, that wouldn't be true. So you can't just say that building new roads won't alleviate traffic, period. There are cases where it is true, and there are cases were adding new roads actually make traffic worse, but there are also cases where adding roads (or tunnels) will alleviate traffic.

by adamjc 10y ago

kavok 10y ago

A tunnel doesn't have to specifically be for cars. Could run busses, trains, etc.. More electric cars on the road though wouldn't output more pollution around the road.

tgb 10y ago
Electric cars are a good match for tunnels: ventilating the tunnel enough for a whole lot of combustion engines to use is a real cost.
- intrasight 10y ago
  And if the tunnel was limited to electric cars (likely), then that would boost Tesla.

Fricken 10y ago

That's the good thinking, but because it isn't intuitive it often gets kicked to the curb by bad thinking. More roads = less traffic, right? right? No? One could also use tunnels to build subways and presumably Hyperloops. I wonder, though, about why big infrastructure projects so horrendously expensive, in America in particular. There are developers, planners, consultants, politicians, unions, contractors, sub contractors, sub-sub contractors, and they're all out for all they can get. There are lawyers every step of the way. Nobody communicates well. Small hang-ups at the wrong place send the entire operation grinding to a halt. Can this be fixed? Is a big dumb tunnel digging operation the point of entry for infrastructure construction disruption in America? That would be nice. We're good at moving the bits around. We suck at atoms. Or is Musk setting himself up to be the next Robert Moses? Someone with the capability to move mountains, but not terribly discriminating about whether or not a given mountain should be moved. Musk doesn't talk like someone who's ever had a discussion with an Urban planner about the real reasons as to why our transportation problems are problems.

nradov 10y ago
US infrastructure construction costs are among the highest in the world. There appear to be multiple root causes including: extensive legal protections for private property owners, environment reviews and lawsuits, need to work across multiple government boundaries, labor laws, union work rules. https://www.bloomberg.com/view/articles/2016-04-08/why-u-s-infrastructure-costs-so-much https://www.bloomberg.com/view/articles/2016-04-08/why-u-s-i... http://www.citylab.com/work/2014/04/7-reasons-us-infrastructure-projects-cost-way-more-they-should/8799/ http://www.citylab.com/work/2014/04/7-reasons-us-infrastruct...

mwill 10y ago

Perhaps not a problem for Musk who also builds cars.

TulliusCicero 10y ago

Presumably the tunnels could also be used for transit, or maybe even walking/biking in some cases.

AYBABTME 10y ago

Tunnels will be required on Mars to shield from radiation. Getting a head start on the technology while on Earth only makes sense. Pretty much everything he plans is in perspective of having a dual use: will it be needed on Mars - SpaceX's true goal? I hate to say the word but, it's all about synergies.

RichardHeart 10y ago

If you move into a bigger house, your hallways will not fill up with more traffic. Currently humans are required at least 1 per car. Thus the housing and employment of those humans is more of a limiting factor on road demand, or perhaps car ownership or desire to drive somewhere, more so than availability of roads.

syberspace 10y ago
Your hallways may not fill up with people, but all your new closets, cupboards, wardrobes, drawers and whatnot will fill up with "stuff"
ericd 10y ago
If roads are clearer, then people tend to move farther from work, which increases the number of cars on the road at any given time. Then the roads clog up again. Increased highway construction has been enabling people to move farther and farther out into exurbs (which people think will be nice places to live, and cheaper, but that turn out create rather shabby quality of life compared to walkable cities).
- Turing_Machine 10y ago
  "(which people think will be nice places to live, and cheaper, but that turn out create rather shabby quality of life compared to walkable cities)." "Shabby quality of life" by whose standards? The people who actually live there? I think not. If life in the suburbs actually sucked, people simply wouldn't stay there. It's not like they're given a one-way exit visa when they leave the city. They could move back any time they wanted. But, as a group, they never do. The reason they don't is because they find the amenities found in the suburbs (in specific, safety, cleanliness, room for their possessions, privacy, and better schools) preferable to those found in the cities. "Preferable" here means preferable by their standards, which are not the same as those of a single 22 year old programmer, or a single 30-something art connoisseur, or...

jessriedel 10y ago

Induced demand often happens, but certainly not always. It just depends on latent demand and network effects. More importantly, the appearance of induced demand is not a general argument against building roads! People get value out of getting to places. If we build road B intending to relieve congestion on road A, but road A stays just as congested, we nevertheless have enabled people to get places with road B that they would not otherwise have been able to reach. That increases utility. All of this applies to mass transit as well. The BART is currently at capacity during rush hour; if a parallel transit line was built, this would probably fill up with people without reducing congestion on BART, but it would still be creating value!

elbigbad 10y ago
Do you happen to have any examples of where induced demand has not happened? My understanding is that it is pretty much guaranteed, especially in larger cities. I think New York's bridges and tunnels are the canonical examples of this. I say pretty much because I assume there must be cases where it didn't happen, but I am unaware of them.
- tgb 10y ago
  Maybe induced demand has always happened, in the sense of demand increasing when the product is more available. But it's plenty common for the amount that demand increases to be less than the amount of extra capacity available. Furthermore, is induced demand that bad? If you double the capacity and it again gets filled to the point of gridlock, well then at least twice as many people are now able to be in gridlock, which they apparently prefer to the alternatives.
  - mnw21cam 10y ago
    The example of when induced demand is bad is when it causes increased pollution. In many parts of the world, there is a deliberate movement towards avoiding building too many roads, in order to decrease road use and therefore pollution levels. However, a car sitting in traffic will produce much more pollution per mile than one travelling at 70mph on a clear road, so the thinking behind this may be flawed.

mason240 10y ago

The idea that we shouldn't build infrastructure because it will get used is one of the more silly talking points out there right now.

Nav_Panel 10y ago
Infrastructure projects should respond to the density and context of the neighborhood. Don't build a low-throughput highway between high density Manhattan and high density western Queens or it'll immediately become congested. Build a train instead. A bias toward highways in cities, which are inherently low throughput, has been the norm and also the problem over the last 80 years of urban infrastructure projects.

foobarrio 10y ago

Then why build roads at all? If N + 1 means more traffic than surely N - 1 means less? So 0 roads, no traffic! Seriously though isn't this a related rates problem? Adding roads adds capacity and also induces demand. Are the two in lockstep? Can the capacity added be greater than the demand induced?

paulddraper 10y ago
Not only that, but the more hyperloops we have, the more overburdened they will be. </s>

angry_napkin 10y ago

If you know 285 has an extra lane now, you'll go ahead and run that errand at a certain time that perhaps you wouldn't have otherwise. Fascinating stuff.

oftenwrong 10y ago

If a restaurant started giving out free food, you wouldn't be surprised when more people than usual went to eat there. Induced demand only happens when the road is underpriced. Any road can be made immune to induced demand by tolling at a price that reflects demand. Too much traffic? Raise the price. Looking a bit empty? Lower the price. Car dependence is only common in the US because drivers do not pay the true cost of driving. Many people could not afford to drive if they had to pay market price to use roads and parking. By disconnecting the cost of transportation from its use, we have evolved a society that is overly dependent on transportation, and that is overly sensitive to increases in transportation costs. This applies to all modes - not just cars.

Tiktaalik 10y ago

If Musk had talked with any expert in transportation at all he'd know that building a tunnel highway won't solve traffic problems in the long term. Either: A) He hasn't talked with any experts at all. B) He doesn't believe the experts. or C) He doesn't think inducing demand is a problem because he owns a car company. None of these possibilities are very good looks.

jldugger 10y ago
> C) He doesn't think inducing demand is a problem because he owns a car company. Just think how bad the smog would be on a car tunnel. Unless they limit it to zero emission vehicles....

paulddraper 10y ago

In economics terms, demand is a relationship between price and quantity demanded. Increasing the supply doesn't affect demand; it just changes the realized price and quantity to another place in the same demand relationship.

artumi-richard 10y ago

There has to be a ceiling to how much demand can be induced.

marssaxman 10y ago
One could view the US Interstate Highway System and its legacy of suburban sprawl as a massive, decades-long effort to reach that ceiling, but we don't appear to have run out of headroom yet.

tunesmith 10y ago

Induced demand is one of those things that always struck me as an abused concept. Yes, it happens, but it's impossible for it to be always true. New roads will attract more traffic, but only up to a point. There exist roads in the United States that aren't experiencing traffic jams at rush hour. If Induced Demand were a law, that wouldn't be true. So you can't just say that building new roads won't alleviate traffic, period. There are cases where it is true, and there are cases were adding new roads actually make traffic worse, but there are also cases where adding roads (or tunnels) will alleviate traffic.