Interesting. I'm assuming it's an unplanned metropolis connecting what were lots of smaller towns/villages, ie like most Old World cities rather than the grid patterns of New World cities. Intrigued as to why it has a city wall... makes me think of the Megacities in Judge Dredd

Just a on roads: transport and communications links are a big part of an evolving city, but your highways don't seem to be continuous, or rather they're quite broken up and tricky to navigate. In an anarchic unplanned city that's fine, but with modern urban planning it's likely various streets would be widened into arterial routes. You see main thoroughfares marked even in mediaeval cities. For this to make sense you'd have to think of where people are travelling to and from within the city.