[peatmoss]

> Then there's also the fact that city planners never manage to build sufficient roads until the current ones are overcrowded.

As a planner, I always find this sentiment amusing. The only thing less popular than being stuck in traffic, is the use of eminent domain that would be required to pave ever larger percentages of our urban land.

Planners can't expand roadways into the 5th dimension. Roads require land--a lot of it in fact. Also, it's not like planners don't anticipate that congestion will be increasing if demand for vehicle travel and population also increase.

Lastly, the prevailing wisdom in planning is that "widening roads to combat congestion is like loosening your belt to combat obesity." There's a popular press book that talks about how increasing roadway capacity can paradoxically worsen traffic: https://books.google.com/books?id=ckLcxEb5tM8C&hl=en