I noticed that about Phoenix the first time I went there. I flew in at night, and the regular grid of street lights was beautiful. This was over 30 years ago, and if I remember correctly there was only a single freeway.

In many places the terrain simply won't allow for a regular grid layout. From my home in Minnesota I can't really go straight north, because there are a number of lakes in the way. There are a couple of roads that manage to snake their way through, but it's all fully built up areas that keep their speed limits low and safe.