I've installed SC4 after being away from the game for a couple of years and downloaded a huge load of plugins, two of them being the NAM and SAM mods. Having built a city I now have No road acces signs over all the residentials. Using the drawpaths command I find every crossroads and each connection to a roundabout have red crosses on them.
I figure it's something of a conflicting mods problem. Rather than removing and re-installing every single plugin, I hope you can tell me this is a known problem. Is it?