I made a few games and demos on the C64 using this technique (switching colours every few raster lines). That part was easy to figure out. The hard bit to my 15-year old self was finding the foreshortening relationship. Through trial and error I finally settled on a lookup table calculated using 1/tan(z)... which as it happens is a good approximation of the true 1/z relation for small angles. Crazy...
There's no need for that. The iPhone's PowerVR chip can push tens of millions of triangles per second (depending on the artificial benchmark used...). It's roughly comparable in capabilities to a Dreamcast (also PowerVR), and ten times better than a Nintendo DS.
Now that every system can produce graphics consisting of a zillion polygons on the fly, why would you want to do a road the old way? Aren't polygons the exact same thing, only better? Well, no. It's true that polygons lead to less distortion, but it is the warping in these old engines that give the surreal, exhillerating sense of speed found in many pre-polygon games. Think of the view as being controlled by a camera. As you take a curve in a game which uses one of these engines, it seems to look around the curve. Then, as the road straightens, the view straightens. As you go over a blind curve, the camera would seem to peer down over the ridge. And, since these games do not use a traditional track format with perfect spatial relationships, it is possible to effortlessly create tracks large enough that the player can go at ridiculous speeds-- without worrying about an object appearing on the track faster than the player can possibly react since the physical reality of the game can easily be tailored to the gameplay style.
Pffft... sorry, that's very nostalgic and all, but if you really wanted non-realistic road effects, you'd still use polygons in any modern implementation. And I know what I'm talking about, I have used both systems.
