So I was zoning my city, doing some experiences and then after I planned the layout of the roads to get the maximum number of High Density buildings back-to-back, I was very happy with the result and started buying the roads and zoning all over the place.
But then, after a while, buildings wanted to upgrade their density so they did it, but noticed that a row of houses didn't increase. Moused over the houses and they said: "Not enough room to increase density"
I checked the size that the houses needed and the little rectangule is green, and green = good to go? (See picture below)
The road of the houses is the best quality, and I dezoned that area just for demonstration. And I don't want houses or anything else in the main avenue.
So.. how is the game not upgrading the houses? Seems like everything (or not, for some reason) is perfect for the grow...