Surprise surprise, more roads leads to more traffic. Reason is, people see how much glorious new road there is, and buy more cars. Probably doesn’t help that many people are getting so fat they can’t do anything BUT drive around.
“If a city had increased its road capacity by 10 percent between 1980 and 1990, then the amount of driving in that city went up by 10 percent. If the amount of roads in the same city then went up by 11 percent between 1990 and 2000, the total number of miles driven also went up by 11 percent. It’s like the two figures were moving in perfect lockstep, changing at the same exact rate.”