R0J0hound - Thank you for your input. That seems to be a bit more feasible. An incredible mental challenge...but feasible.
Taking into account what you've gone over...
Road types: While I would love to have a game along the lines of Need For Speed: Most Wanted (my favorite full-city sandbox racing game) with all manner of city road types, I plan to keep the road types/widths uniform. I don't think there will be any real exceptions even when it comes to the awkward-angled intersections. For the game missions, there might be some unique side roads or "pit stop" areas, but nothing exotic or exceedingly out of the norm.
Intersections: Probably the most challenging given the layout of the city. The trick will be how to merge two sides of the roads coming together when the road lines are considered. Alternatively, I could simply draw custom sprites for the intersections. It would be a lot...but far better than trying to work out a system to merge roads...especially ones coming in at angles.
Road heights and bridges: My plan so far is to have 3 levels, minimum: Ground level, upper level (overpasses, "major" roadways that act kinda like shortcuts between districts), and underground. Alternatively, I was thinking about having the "ground level" have its own progressive elevations throughout the city...much like the real city this is based on. But initial efforts have proven this may not be as timely as I'd like as it would require a lot of manual editing. I'm probably going to resort to keeping the ground level completely flat and having the roads shift between specified elevation levels or just keep it at a strict "ground", "upper", and "underground" for simplicity...
Analog roads: And that's where the trick comes in. The careful plotting of road pieces - many, many of them - that create the semblance of progressive turns and angles. Without drawing them out, the angles of the straight roads connecting will be obvious. That's fine. All of that you mentioned. Then I could connect them all by the custom-drawn intersections sprites.
Drawing roads in-game: My plan does include road segments being constructed along the lengths of lines placed in the editor and then actually spawned when the player car is within range. I've also been trying to figure out if utilizing an Array contained with respective road pieces might help generate roads in-game when the player is nearby.