Vulgar as it may be to actually say it in public, and except for the unusual circumstance in which there is no required parking (definitely rare in North America) urban design starts with parking. You may not want to believe it, but that is the cold hard reality.
I was chatting with an architect. We were discussing a small condominium project. Very large buildings came up. I happened to ask him if he had worked on one.
"Yes when I a young associate at a big firm."
"Oh, they must be exceedingly difficult to design."
"No not really."
"No it's true. For one thing most of the work is done by the structural engineer and contractor who lay out the basic grid. The architect's fundamental job is getting the cars onto and off the site. You can route people up ramps and stairs and so forth. But cars are much more difficult. There are consideration of grades and transitions and turning radii. The real design turns on parking."
"No, look at it with this project, here. What's the very first thing we did? Long before we even started to look at the apartment layouts? We looked at how we would get cars onto and off the site...and how we could arrange the parking layout. Only then did we look at the building itself. Parking is the tail that wags the building."