New road schemes and proposals maps - Public forum - Planning Advisory Service (PAS)

We are currently trying to find the best way to show new road schemes on our proposals maps. There seems to be little guidance within PPS12 and even less in the draft NPPF! Would be interested to know how others are approaching this and what level of detail is behind the line on the map - are the road lines detailed at this stage or are they merely an indicative line that will gather more detail at a later stage? Any ideas/examples would be appreciated!