Fix: One-way roads could be over-built by road stops (regardless of road owner.)

src/lang/english.txt

@@ -4234,6 +4234,7 @@ STR_ERROR_DRIVE_THROUGH_ON_TOWN_ROAD                            :{WHITE}... this
 STR_ERROR_DRIVE_THROUGH_DIRECTION                               :{WHITE}... road facing in the wrong direction
 STR_ERROR_DRIVE_THROUGH_CORNER                                  :{WHITE}... drive through stops can't have corners
 STR_ERROR_DRIVE_THROUGH_JUNCTION                                :{WHITE}... drive through stops can't have junctions
+STR_ERROR_DRIVE_THROUGH_ON_ONEWAY_ROAD                          :{WHITE}... road is one way or blocked
 
 # Station destruction related errors
 STR_ERROR_CAN_T_REMOVE_PART_OF_STATION                          :{WHITE}Can't remove part of station...

src/station_cmd.cpp

@@ -960,6 +960,8 @@ static CommandCost CheckFlatLandRoadStop(TileArea tile_area, DoCommandFlag flags
 					num_roadbits += CountBits(GetRoadBits(cur_tile, ROADTYPE_ROAD));
 				}
 
+				if (GetDisallowedRoadDirections(cur_tile) != DRD_NONE) return_cmd_error(STR_ERROR_DRIVE_THROUGH_ON_ONEWAY_ROAD);
+
 				/* There is a tram, check if we can build road+tram stop over it. */
 				if (HasBit(cur_rts, ROADTYPE_TRAM)) {
 					Owner tram_owner = GetRoadOwner(cur_tile, ROADTYPE_TRAM);