[dragonwriter]

Traffic impacts that are created by increasing occupancy faster than new infrastructure can be built have adverse impacts on everyone using the transport infrastructure just like a polluting industry has an adverse impact on the area (also, it has a pollution impact, whether or not infrastructure is adequate, but that's probably generally not as big of a concern.) So, scale can make new office space a noxious impact, and the article seems to clearly indicate that a preexisting overall scale limit was applied and Google, who had asked for most of it, got far less, and LinkedIn got the lion's share.