Okay, the traffic simulator project has been slow going over the past few weeks, just not been very focussed and playing with DLA and other assignments too much.
This morning/arvo I changed some of the code and layout of how cars were being generated. Now instead of a car know what road it is on it has been reversed, so each road has its own collection of cars to manage. With some changes to how the graphics are produced this now means that cars are now rendered at the same time as each road. A that allows perfect placement of cars onto roads rather than having to do a mathematically approximation. Clear as mud?