I just updated my PostGIS-reader for GraphHopper version 4.0, and added functionalities to include Turn Restrictions and Conditionals data on graph creation.
With this reader, it will be possible to use non-OSM, 3rd party road networks with GraphHopper (we have several providers of road data here in Japan). Also, by using QGIS with the road network, it is easily possible to add or modify turn restrictions and conditionals on a regular basis.
If somebody might find this useful, the source and a little documentation can found here:
and a V4.0 source that includes this reader is here: