Downs–Thomson paradox

There are many multiple reasons that lead to this.

For example, it's usually easier to increase the 'main arteries' of the road network. Just widen the road or build more roads. This option usually goes away close to the destination.

If you just keep building more highways, you end up with hurry up and wait situations where the congestion starts close to the destination and spreads backwards. Cars are waiting to exit highways in the mornings and streets leading to highways are full in the evening.

If you solve all these issues and build enough highways, entries, exists, streets etc. you end with a sparse city. Traffic is faster but distances are long. More traffic is needed because walking distances disappear.

Discussed a couple of days ago in the context of average Uber speeds in London and other congested cities [1].

[1] https://news.ycombinator.com/item?id=20113084

This may apply in part, or in limited circumstances, such as those where mass transit was a viable option to begin with.

But road capacity has increased with population growth, another factor behind why road capacity over the long term may not yield the expected results in relieving congestion, though congestion would be worse without those improvements.

From my own annecdotal experience in some of the most heavily trafficked roads in the tri-state area, capacity increases have absolutely improved congestion. Conversion from a two Lane to a three lane highway in one area about 15 years ago cut off at least 20 minutes of travel time even during peak traffic times.

I've started to cheat congestion to get away from this paradox by commuting at 10am and 3pm. I'll work-from-home for 5 hours per day and work in the office for 4. That extra hour I save commuting is put towards getting ahead at work.

I would like to be able to optimize this further and WFH fully for 1 or 2 days and schedule all in person interaction on 3 other days but my work has an official no work from home policy so I can't implement that on my team. I can only take advantage of the "flexibility" as they call it