Were you aware that Ocean Quigley also worked on the beautiful SimCity 4?  I didn’t until today (I never paid much attention to the credits in the manuals).  He has posted a couple of development pictures of the game in his blog.

I’m particularly proud of the roads and networks. They’re composed of hundreds of different tiles that could combine in thousands of ways (intersections of all sorts, and connections between roads and highways, roads and rail, etc.).

And we had to figure out how to conform the terrain to them, adding bridges, leveling, making retaining walls, and the like. And it had to be seamless, so that the player would just draw out what they wanted and the system would figure out what to do automatically.

Designing them was like taking a 6 month long IQ test. These are a few design prototypes that helped me to think through some of the problems.