The article is here. The American Society of Landscape Architects, has a blog that links to the article and comments from some of the  landscape architects:

“Think about trying to create a scaled, interesting park space underneath a 30 foot  high elevated 10-lane highway. It will take an extremely creative design team to pull this off.

Additionally, will roads be allowed to cut underneath the building? With the footprint being so linear, are the developers setting up a “superblock” or “radiant city” scenerio, where streetscapes and human scaled elements dominate rather than vast expanses of park land?”