> The problem with induced demand is that yes you increase capacity and more people then move clogging up the roads until a similar equilibrum is reached as before.
That's still an improvement over the previous status quo. Commute times are not the only, or even necessarily the most important factor in a transportation system. Your new equilibrium transports a larger number of people than the previous equilibrium. In isolation, that's purely a good thing.
In a world where road users paid for those improvements directly in proportion to their use of the road we could just keep expanding capacity indefinitely until either all the latent demand were met, or until rising construction costs drove demand down to a level where the roads were no longer congested. Since roads are funded by income taxes though, a crucial half of that feedback loop is missing. We can't just keep expanding because there's nothing to stop road users from demanding more and more capacity even after adding that capacity becomes cost-prohibitive.
Yes, but that's conveniently ignoring all of the negative externalities produced by it.
So adding roads gets half the benefits (as it doesn't gain any efficiency benefits), and comes with a ton of externalities when compared to mass transit.
That's still an improvement over the previous status quo. Commute times are not the only, or even necessarily the most important factor in a transportation system. Your new equilibrium transports a larger number of people than the previous equilibrium. In isolation, that's purely a good thing.
In a world where road users paid for those improvements directly in proportion to their use of the road we could just keep expanding capacity indefinitely until either all the latent demand were met, or until rising construction costs drove demand down to a level where the roads were no longer congested. Since roads are funded by income taxes though, a crucial half of that feedback loop is missing. We can't just keep expanding because there's nothing to stop road users from demanding more and more capacity even after adding that capacity becomes cost-prohibitive.