[jacques_chester]

> because the effing bus doesn't go where 50 random people need to go

This would be a problem if the random destinations were uniformly distributed. They are not. They cluster. And indeed there is a feedback loop between public transport and destination desirability.

> It's impossible because total traffic cannot increase due to new roads since there aren't infinite people or cars to begin with. The traffic moving to new or wider roads is missing elsewhere, which is usually good.

It sounds like you think induced demand is an instantaneous phenomenon. It's not. It's a dynamic system with a variety of stocks and therefore, a variety of delayed effects that show up over spans of time.

But you can simplify it to an abstract model: supply and demand. You can fairly say that there is a supply of car travel and a demand for car travel.

If you lower the cost of something then, all things being equal, the demand rises. If you make car travel faster and more pleasant than it was previously, then demand goes up until it reaches an equilibrium again. It's easy to estimate where that equilibrium lies: around the current travel time for a road before it is expanded. But then the net cost for other uses of the space has risen, because there is less to go around.

Roads are not immune from economics, just as they are not excused from geometry.

[lazyjones]

> If you lower the cost of something then, all things being equal, the demand rises

No. Only in abstract models with potentially infinite supply and demand. If you lower the cost of plaster casts, more people won't break their legs.

> Roads are not immune from economics, just as they are not excused from geometry.

And economics aren't immune from ideology and disingenuous modelling.

[jacques_chester]

> If you lower the cost of plaster casts, more people won't break their legs.

Now you're misunderstanding elasticity of demand and assuming that demand or supply curves are perfectly linear.

Plaster casts are highly inelastic, but if I jacked the price to $100,000 per, demand will fall off fairly sharply.

> And economics aren't immune from ideology and disingenuous modelling.

My experience is that economists know more about economics than people who beat up the strawman versions.

Your position, as I understand it, is that some other model correctly describes the demand for road travel. What is it? And why is road travel the exception?

[lazyjones]

> My experience is that economists know more about economics than people who beat up the strawman versions.

And mine is that economists disagree with each other more than with anyone else.

> Your position, as I understand it, is that some other model correctly describes the demand for road travel. What is it? And why is road travel the exception?

What model specifically are you talking about? We have N lanes going from A to B, if we add 1 lane, total traffic from A to B will increase regardless of any other circumstances? Is that it?