[dsfyu404ed]

The severity of congestion at peak demand is governed by what people will tolerate. The duration of congestion is what changes when you change capacity. Even if you doubled the amount of every form of transit overnight the severity of congestion at peak would quickly reach equilibrium at about the same level as before.

Peak demand for transit (road, rail, etc) will always exceed available supply as long as the population of people moving at peak is larger than the instantaneous capacity of your transit system. Adding more capacity will always help the overall situation because it shortens the length of the time the that demand is higher than supply.

It's like how course registration at universities tends to saturate the systems involved. Peak demands will always slow things to a crawl but additional capacity is beneficial because it shortens the time the service is degraded. Adding transit of any type doesn't make rush "hour" suck less, it makes rush hour shorter.

edit:rearranged to more clearly make my point

[gowld]

Your comment is more correct if you remove the "No."

"Less congestion" can mean either "shorter span of time" as you further explained, or "less congested at some time point".

The former should be what readers jump to, because "congestion" is nearly binary at a moment in time -- either traffic is flowing smoothly (1-2x optimal travel time) or it is clogged (>2x travel time). "Slightly clogged" isn't really an important case for travelers.