It's much better for the environment to pack the people into a dense urban area where they area easily served by transit (or can walk to where they want to go),

It's much better for the environment to pack the people into a dense urban area where they area easily served by transit (or can walk to where they want to go), goods delivery, etc than to have people commuting 60 miles from Tracy where they live in a 3000 sq foot house on a half acre of land.