diff --git a/src/Airports/GenAirports850/airport.cxx b/src/Airports/GenAirports850/airport.cxx
index 466ef46f..7a65a789 100644
--- a/src/Airports/GenAirports850/airport.cxx
+++ b/src/Airports/GenAirports850/airport.cxx
@@ -295,6 +295,7 @@ void Airport::BuildBtg(const string& root, const string_list& elev_src )
     TGPolygon base_poly    = tgPolygonDiff( divided_base, accum );
 
     // do this when generating the polys themselves...
+#if 0
     for ( k = 0; k < (int)rwy_polys.size(); ++k ) 
     {
     	SG_LOG(SG_GENERAL, SG_DEBUG, "add nodes/remove dups section = " << k << " " << rwy_polys[k].get_material());
@@ -339,6 +340,7 @@ void Airport::BuildBtg(const string& root, const string_list& elev_src )
     	rwy_polys[k].set_poly( poly );
     }
     // END do this when generating polys
+#endif
 
     // add segments to polygons to remove any possible "T"
     // intersections
diff --git a/src/Airports/GenAirports850/closedpoly.cxx b/src/Airports/GenAirports850/closedpoly.cxx
index cf705f6d..35cfaa96 100644
--- a/src/Airports/GenAirports850/closedpoly.cxx
+++ b/src/Airports/GenAirports850/closedpoly.cxx
@@ -598,7 +598,20 @@ int ClosedPoly::BuildBtg( float alt_m, superpoly_list* rwy_polys, texparams_list
     string material;
     int j, k;
 
-    material = "pa_tiedown";
+    switch( surface_type )
+    {
+        case 1:
+            material = "pa_tiedown";
+            break;
+
+        case 2:
+            material = "pc_tiedown";
+            break;
+
+        default:
+            SG_LOG(SG_GENERAL, SG_DEBUG, "ClosedPoly::BuildBtg: unknown material " << surface_type );
+            exit(1);
+    }
 
     // verify the poly has been generated
     if ( pre_tess.contours() )    
@@ -622,17 +635,16 @@ int ClosedPoly::BuildBtg( float alt_m, superpoly_list* rwy_polys, texparams_list
         TGTexParams tp;
 
         TGPolygon clipped = tgPolygonDiff( pre_tess, *accum );
-
         SG_LOG(SG_GENERAL, SG_DEBUG, "BuildBtg: clipped poly has " << clipped.contours() << " contours");
 
         TGPolygon split   = tgPolygonSplitLongEdges( clipped, 400.0 );
-
         SG_LOG(SG_GENERAL, SG_DEBUG, "BuildBtg: split poly has " << split.contours() << " contours");
 
-
         sp.erase();
         sp.set_poly( split );
         sp.set_material( material );
+        sp.set_flag("taxi");
+
         rwy_polys->push_back( sp );
         SG_LOG(SG_GENERAL, SG_DEBUG, "clipped = " << clipped.contours());
         *accum = tgPolygonUnion( pre_tess, *accum );
diff --git a/src/Airports/GenAirports850/runway.cxx b/src/Airports/GenAirports850/runway.cxx
index 9b4f5328..57aae4d3 100644
--- a/src/Airports/GenAirports850/runway.cxx
+++ b/src/Airports/GenAirports850/runway.cxx
@@ -9,6 +9,7 @@
 #include <osg/Geometry>
 #include <osg/Group>
 
+#include <Geometry/poly_support.hxx>
 #include <Polygon/polygon.hxx>
 
 #include "beznode.hxx"
@@ -267,6 +268,13 @@ void Runway::gen_simple_rwy( double alt_m, const string& material, superpoly_lis
     	SG_LOG(SG_GENERAL, SG_DEBUG, " point = " << p);
     }
 	
+    // do this before clipping and generating the base
+    runway_a = remove_dups( runway_a );
+    runway_a = reduce_degeneracy( runway_a );
+
+    runway_b = remove_dups( runway_b );
+    runway_b = reduce_degeneracy( runway_b );
+
     TGSuperPoly sp;
     TGTexParams tp;