In general housing plan development maps are not suitable sources for OSM. They usually contain copyright information owned by the developer and proprietary map data (e.g., in Great Britain, from OSGB Master Map). Additionally some plans are not true plans but schematics which are not to scale.
The simplest way to add the roads is to use a GPS (mobile phone will do fine) and walk or drive around the estate. GPS traces can be uploaded to OSM and then used within an editor to add the roads. Various apps allow collection of GPS traces including OSM Tracker and OSMand. The main access/distributor road is the most important one to get right. The location of side roads can be estimated and the accuracy of the road network refined over time. This is how much of Britain was mapped on OSM until 2010.
Depending where you are based there may also be other usable sources. For instance in Britain the Ordnance Survey produces open data files of the national road network which are updated every 6 months or so. It’s also worth checking through all the imagery layers (ESRI, Digital Globe & Mapbox) in case there is newer imagery available.
If you let us know where you are others may be able to help find suitable resources to help. (I’m guess you’re in the UK because of talking about housing estates, and probably here in which case the Digital Globe Standard imagery is recent enough to see roads and many houses).