Metro PHX population is smaller by about 2.5 million. In terms of area, metro PHX is about 14.5K square miles compared to metro DFW's ~9.3K. I guess that's why Dallas always seems more "crowded" to me than Phoenix - it literally is.

I personally find Dallas area traffic usually much worse than that in the Valley. Not as bad as Boston; certainly nothing like Roma.

Aside: Didn't you just recently move back to Scottsdale?