diff --git a/src/micropolisj/engine/Bulldozer.java b/src/micropolisj/engine/Bulldozer.java
index 003fc2b..be97228 100644
--- a/src/micropolisj/engine/Bulldozer.java
+++ b/src/micropolisj/engine/Bulldozer.java
@@ -47,7 +47,7 @@ class Bulldozer extends ToolStroke
 		assert isZoneCenter(currTile);
 
 		eff.spend(1);
-		switch (checkSize(currTile))
+		switch (getZoneSizeFor(currTile))
 		{
 		case 3:
 			eff.makeSound(0, 0, Sound.EXPLOSION_HIGH);
@@ -108,28 +108,4 @@ class Bulldozer extends ToolStroke
 		}
 		fixBorder(eff, w, h);
 	}
-
-	int checkSize(int tile)
-	{
-		tile = tile & LOMASK;
-		if ((tile >= (RESBASE-1) && tile <= (PORTBASE-1)) ||
-			(tile >= (LASTPOWERPLANT+1) && tile <= (POLICESTATION+4)))
-		{
-			return 3;
-		}
-		else if ((tile >= PORTBASE && tile <= LASTPORT) ||
-			(tile >= COALBASE && tile <= LASTPOWERPLANT) ||
-			(tile >= STADIUMBASE && tile <= LASTZONE))
-		{
-			return 4;
-		}
-		else if (tile == TileConstants.AIRPORT)
-		{
-			return 6;
-		}
-		else
-		{
-			return 0;
-		}
-	}
 }
diff --git a/src/micropolisj/engine/TileConstants.java b/src/micropolisj/engine/TileConstants.java
index 7068f99..74a1da7 100644
--- a/src/micropolisj/engine/TileConstants.java
+++ b/src/micropolisj/engine/TileConstants.java
@@ -426,15 +426,27 @@ public class TileConstants
 	public static int getZoneSizeFor(int tile)
 	{
 		int ch = tile & LOMASK;
-		if (ch < PORTBASE) {
+		if (ch >= RESBASE && ch < PORTBASE) {
 			return 3;
 		}
-		else if (ch == AIRPORT) {
+		else if (ch >= PORTBASE && ch <= LASTPORT) {
+			return 4;
+		}
+		else if (ch >= AIRPORTBASE && ch < COALBASE) {
 			return 6;
 		}
-		else {
+		else if (ch >= COALBASE && ch <= LASTPOWERPLANT) {
 			return 4;
 		}
+		else if (ch >= FIRESTBASE && ch < STADIUMBASE) {
+			return 3;
+		}
+		else if (ch >= STADIUMBASE && ch <= LASTZONE) {
+			return 4;
+		}
+		else {
+			return 0;
+		}
 	}
 
 	public static boolean isConstructed(int tile)