Actually it was planned to have a lot more green space (the blocks were only supposed to have housing on two sides so as to leave the other sides unimpeded), but market forces prevailed, and all the green space is now walled off. Shame.
The district is still a lot more liveable than basically any place I've seen in North America, however.
I stayed off the Urquinaona a couple weeks ago and really enjoyed that area of the city. Yes, there was a pretty high amount of vehicular traffic around that area, but it was full of street life and an easy base to get around the city from.
