Serious application for these tools: crowded countries like the UK often talk about building new towns rather than annoying everyone is existing towns by more and more building work. Unfortunately, new towns tend to be rather formulaic and dull. With tools like these, you could start with a medieval city generator and use algorithms to apply changes that would have happened over 500 years and then build the new town…
One problem. Cars! Unless you can lay down some serious infrastructure as a constraint first hand. Driving in these types of places is always insane. Just look at Italy. It'd be an easy problem to solve by pushing for a carless city or smaller car city paradigm. But folk will want their cars.
That allows for 1 or 2 stories of parking for each steel+concrete building, a double-height lobby level, with a bicycle-locker mezzanine, the possibility of double-height train stations built into buildings adjoining a mechanical floor, and "streets" that are narrower for walkers than for cars.
I'd bet that the cost of putting a 7m deck over every road you pave, or at least an elevated walkway 2m wide, is easily saved by subtracting the sidewalk width from the ground-level road footprint, allowing greater building density. A 21.25m road footprint can fit 4 3.25m travel lanes, one 2.75m center turning lane, and two 2.75m right-turn/breakdown lanes. A 12m footprint can hold 2 3.25m travel lanes and 2 2.75m turn/breakdown lanes. Additionally, above the 7m vehicle clearance level, buildings can be cantilevered over the roadway, making the pedestrian "street" narrower than the road-for-cars below.
In the US, the usual minimum acceptable neighborhood curb-to-curb street width is 8.5m, but then add sidewalks for a total footprint of 15.25m. Some neighborhoods allocate 18.25m for the right-of-way, with 12m for the road, then they add infuriating speed bumps. In Chicago[0], the major arterials are 30.5m wide, with at least 20% pedestrian width; minor arterials and collectors are 20m wide, with 33% for pedestrians. It's all based on the 66ft surveyor's chain. Stack the sidewalk over the street, and you give your city greater areal density and better use of available volume.
[0] https://www.cityofchicago.org/dam/city/depts/cdot/StreetandS...