diff --git a/OpenRa.FileFormats/Map.cs b/OpenRa.FileFormats/Map.cs
index 4776132f25..8e2d0c85f3 100644
--- a/OpenRa.FileFormats/Map.cs
+++ b/OpenRa.FileFormats/Map.cs
@@ -126,6 +126,11 @@ namespace OpenRa.FileFormats
 			foreach( KeyValuePair<string, string> kv in terrain )
 				Trees.Add( new TreeReference( int.Parse( kv.Key ), kv.Value ) );
 		}
+
+		public bool IsInMap(int x, int y)
+		{
+			return (x >= XOffset && y >= YOffset && x < XOffset + Width && y < YOffset + Height);
+		}
 	}
 
 	public struct TileReference
diff --git a/OpenRa.FileFormats/TileSet.cs b/OpenRa.FileFormats/TileSet.cs
index 170cafca6e..cec71e1ad0 100644
--- a/OpenRa.FileFormats/TileSet.cs
+++ b/OpenRa.FileFormats/TileSet.cs
@@ -9,7 +9,8 @@ namespace OpenRa.FileFormats
 	public class TileSet
 	{
 		public readonly Dictionary<ushort, Terrain> tiles = new Dictionary<ushort, Terrain>();
-		public readonly Dictionary<ushort, Dictionary<int, int>> walk = 
+
+		readonly Dictionary<ushort, Dictionary<int, int>> walk = 
 			new Dictionary<ushort, Dictionary<int, int>>();	// cjf will fix
 
 		public readonly Package MixFile;
@@ -78,5 +79,13 @@ namespace OpenRa.FileFormats
 
 			return missingTile;
 		}
+
+		public int GetWalkability(TileReference r)
+		{
+			if (r.tile == 0xff || r.tile == 0xffff)
+				r.image = 0;
+
+			return walk[r.tile][r.image];
+		}
 	}
 }
diff --git a/OpenRa.Game/PathFinder.cs b/OpenRa.Game/PathFinder.cs
index 96692dc711..9271b6525a 100644
--- a/OpenRa.Game/PathFinder.cs
+++ b/OpenRa.Game/PathFinder.cs
@@ -29,26 +29,16 @@ namespace OpenRa.Game
 			}
 		}
 
-		public PathFinder( Map map, TileSet tileSet )
+		public PathFinder(Map map, TileSet tileSet)
 		{
 			this.map = map;
 
-			for( int x = 0 ; x < 128 ; x++ )
-			{
-				for( int y = 0 ; y < 128 ; y++ )
-				{
-					if (x < map.XOffset || y < map.YOffset || x >= map.XOffset + map.Width || y >= map.YOffset + map.Height)
-						passable[x, y] = false;
-					else
-					{
-						TileReference r = map.MapTiles[x, y];
-						if (r.tile == 0xffff || r.tile == 0xff)
-							r.image = 0;
+			//todo: speed hax for roads
 
-						passable[x, y] = IsPassable(tileSet.walk[r.tile][r.image]);
-					}
-				}
-			}
+			for (int x = 0; x < 128; x++)
+				for (int y = 0; y < 128; y++)
+					passable[x, y] = map.IsInMap(x, y) && 
+						IsPassable(tileSet.GetWalkability(map.MapTiles[x, y]));
 		}
 
 		public List<int2> FindUnitPath( World world, Unit unit, int2 destination )