[bryanlarsen]

"Demand is a good thing because it's economic activity that wouldn't have happened if the piece of infrastructure in question wasn't built out."

It's economic activity that has a huge amount of negative externalities and infrastructure cost. So if the economic activity generated has a value less than that of the externalities and costs, society is worse off.

So we need a way of limiting demand so that any trip whose benefit is less than its infrastructure and negative externalities doesn't happen.

Currently we mostly do this by making trips really slow and annoying during rush hour. There's obviously a better way but tolls are political suicide.