[paulgb]

> That's the fundamental argument against the assertion that traffic speed increases will offset the costs. It cannot be true, or people would choose to drive.

I think the mistake you're making here is assuming that the value of driving and the cost of congestion are the same to every driver.

For some people, driving is an elastic decision. They mode shift, or time shift to off-peak, or carpool, or combine errands in the city into one trip instead of multiple.

For other people, driving is necessary. They'll benefit from fewer of the first type of person being on the roads during peak hours.

[josephcsible]

> time shift to off-peak

One of the worst things about this congestion charge is that it applies even at off-peak times.

[paulgb]

It’s 75% lower off-peak though, so there’s still an incentive.

[timr]

No, I don't need to make assumptions about any of that. It's a complex interplay of factors (like any economic system), and everyone has their own reward function.

I'm just saying that if the marginal driver were still choosing to drive, then the system wouldn't work at all. That seems tautological?

The MTA has to set the price high enough above market that the reduction in demand is X%. Whether someone is driving because of speed, or comfort, or some other factor, the cost has to exceed their personally calculated benefit.

[paulgb]

> Whether someone is driving because of speed, or comfort, or some other factor, the cost has to exceed their personally calculated benefit.

It's a dynamic system though; as some drivers opt not to drive, the utility of driving for those other drivers increases. Yes, the market will find an equilibrium somewhere where some people will still drive, but that's kind of the point.

[timr]

I think the better argument for your side is that a large number of people have a utility function that isn't rational -- or at least, not based on commute time saved.

Yes, the market will find a new equilibrium, but if I'm right that the marginal driver is choosing to drive or not based mostly on a function of time saved, then eventually we'll see the market reaching an equilibrium where people are willing to pay up to the amount of money they save by getting somewhere faster via car (ignoring other costs for the sake of argument).

If that is true -- if the market is efficient for time -- then this plan can only ever work by making driving more expensive than the time lost to congestion.

(As an aside, thanks for having a serious, nuanced discussion about this. It's depressing how many people just want to fling insults and downvote/flag/censor stuff that they disagree with. I knew I was going to get ravaged for having a non-canonical opinion, but it's so hard to get people to just engage with the argument in good faith.)