> Congestion indicates transportation capacity is below demand. But once the medium is congested, you can't measure what the demand is; only how long it's conge

> Congestion indicates transportation capacity is below demand. But once the medium is congested, you can't measure what the demand is; only how long it's congested. But congestion is also part of what controls the demand. It's not a "true" demand that you're just not seeing because of congestion. Once the congestion is solved, the demand will increase as that changes the attractiveness of driving. Since driving then for some people will outcompete bus, cycling, trains etc., they will then shift over to driving even though they had no demand for it earlier. It will then reach a new equilibrium, not far off the old congestion.