Index: src/town_cmd.cpp
===================================================================
--- src/town_cmd.cpp	(Revision 11005)
+++ src/town_cmd.cpp	(Arbeitskopie)
@@ -577,15 +577,6 @@
 	{ 0,  1}
 };
 
-/**
- * Distance multiplyer
- * Defines the possible distances between 2 road tiles
- */
-enum RoadBlockTitleDistance {
-	RB_TILE_DIST1 = 1, ///< 1 tile between
-	RB_TILE_DIST2,     ///< 2 tiles between
-};
-
 static bool GrowTown(Town *t);
 
 static void TownTickHandler(Town *t)
@@ -645,14 +636,28 @@
  * @param dir target direction
  * @param dist_multi distance multiplyer
  * @return true if one of the neighboring tiles at the
- *  given distance is a road tile else
+ *  given distance is a road tile else false
  */
-static bool IsNeighborRoadTile(TileIndex tile, int dir, RoadBlockTitleDistance dist_multi)
+static bool IsNeighborRoadTile(TileIndex tile, int dir, int dist_multi)
 {
-	return (HASBIT(GetTownRoadMask(TILE_ADD(tile, dist_multi * ToTileIndexDiff(_roadblock_tileadd[dir + 1]))), dir ^ 2) ||
-			HASBIT(GetTownRoadMask(TILE_ADD(tile, dist_multi * ToTileIndexDiff(_roadblock_tileadd[dir + 3]))), dir ^ 2) ||
-			HASBIT(GetTownRoadMask(TILE_ADD(tile, dist_multi * (ToTileIndexDiff(_roadblock_tileadd[dir + 1]) + ToTileIndexDiff(_roadblock_tileadd[dir + 2])))), dir) ||
-			HASBIT(GetTownRoadMask(TILE_ADD(tile, dist_multi * (ToTileIndexDiff(_roadblock_tileadd[dir + 3]) + ToTileIndexDiff(_roadblock_tileadd[dir + 2])))), dir));
+	static TileIndexDiff tid_lt[3]; ///< lookup table for the used diff values
+	tid_lt[0] = ToTileIndexDiff(_roadblock_tileadd[dir + 1]);
+	tid_lt[1] = ToTileIndexDiff(_roadblock_tileadd[dir + 3]);
+	tid_lt[2] = ToTileIndexDiff(_roadblock_tileadd[dir + 2]);
+
+	for (uint pos = (dist_multi * 4) - 1; pos != 0; pos--) {
+		TileIndexDiff cur = 0;
+		/* For each even value of pos add the left TileIndexDiff
+		 * for each uneven value the right TileIndexDiff
+		 * for each with 2nd bit set (2,3,6,7,..) add the reversed TileIndexDiff
+		 */
+		cur += tid_lt[(pos & 1) ? 0 : 1];
+		if (pos & 2) cur += tid_lt[2];
+
+		cur = ((uint)(pos / 4) + 1) * cur; ///< Multiply for the fitting distance
+		if (HASBIT(GetTownRoadMask(TILE_ADD(tile, cur)), (pos & 2) ? dir ^ 2 : dir)) return true;
+	}
+	return false;
 }
 
 static bool IsRoadAllowedHere(TileIndex tile, int dir)
@@ -685,11 +690,10 @@
 				default: NOT_REACHED();
 
 				case TL_ORIGINAL: /* Disallow the road if any neighboring tile has a road (distance: 1) */
-					return !IsNeighborRoadTile(tile, dir, RB_TILE_DIST1);
+					return !IsNeighborRoadTile(tile, dir, 1);
 
 				case TL_BETTER_ROADS: /* Disallow the road if any neighboring tile has a road (distance: 1 and 2). */
-					return !(IsNeighborRoadTile(tile, dir, RB_TILE_DIST1) ||
-							IsNeighborRoadTile(tile, dir, RB_TILE_DIST2));
+					return !IsNeighborRoadTile(tile, dir, 2);
 			}
 		}