Well, this is really a two-way problem. Being mostly a pedestrian myself (I don't own a car, and only use one of them very occasionally to cover long distances or move furniture), I really enjoy old historic city centres, which are really easy to get around just walking.
Being a pedestrian in a car-first environment can really be nightmarish (and dangerous!) at times. I think about large shopping centers or industrial complexes, but also about American-type suburbs. Getting around is impractical, public transport i often nonexistent. As a results, this only encourages car ownership, which encourages building this kind of environment.
However, I also drive quite a bit at times, mostly in the countryside, yet I would take an easily accessible parking lot and public transit infrastructure in big cities over large roads. I don't really know about elsewhere, but it seems to me that car-less cities are pushed for in quite a number of places in Europe, and it doesn't seem like the opposite (making cities more car-friendly) pushes back that much in cities that were converted.
Now, about the parent, this could be taken a step further by optimizing for a lot of variables (walking time, access to public transportation, parkings, roads, etc), instead of just making an "historic simulation".
You really need to grade-separate car traffic, public transit traffic, bicycles, and pedestrians. If you set your citywide story height to be 3.5m, you can put the automobile traffic at ground level, the pedestrian deck at +7m, and in the city center, also elevated bicycle lanes at +10.5m, and elevated trains at +14m.
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.
I just spent some time driving in the Italian countryside. Dreadful if you are used to relatively newer infrastructure, but the people that are used to it don't seem to have an issue! It was terrifying.
Medieval cities were limited by the size of the fortification walls, so streets had to be as narrow as possible to save the valuable space. You don't have such limits with this, so you can turn all streets into boulevards if you like...
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.