diff --git a/brouter-codec/src/main/java/btools/codec/MicroCache2.java b/brouter-codec/src/main/java/btools/codec/MicroCache2.java
index d149f0e..98653cb 100644
--- a/brouter-codec/src/main/java/btools/codec/MicroCache2.java
+++ b/brouter-codec/src/main/java/btools/codec/MicroCache2.java
@@ -3,8 +3,8 @@ package btools.codec;
 import java.util.BitSet;
 import java.util.HashMap;
 
-import btools.util.ByteArrayUnifier;
 import btools.util.ByteDataReader;
+import btools.util.IByteArrayUnifier;
 
 /**
  * MicroCache2 is the new format that uses statistical encoding and
@@ -28,7 +28,7 @@ public final class MicroCache2 extends MicroCache
     latBase = latIdx*cellsize;
   }
   
-  public byte[] readUnified( int len, ByteArrayUnifier u )
+  public byte[] readUnified( int len, IByteArrayUnifier u )
   {
   	byte[] b = u.unify( ab, aboffset, len );
   	aboffset += len;
diff --git a/brouter-expressions/src/main/java/btools/expressions/BExpressionContext.java b/brouter-expressions/src/main/java/btools/expressions/BExpressionContext.java
index 07357da..8d3e8df 100644
--- a/brouter-expressions/src/main/java/btools/expressions/BExpressionContext.java
+++ b/brouter-expressions/src/main/java/btools/expressions/BExpressionContext.java
@@ -14,15 +14,16 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Random;
 import java.util.StringTokenizer;
 import java.util.TreeMap;
 
 import btools.util.BitCoderContext;
 import btools.util.Crc32;
-import java.util.Random;
+import btools.util.IByteArrayUnifier;
 
 
-public abstract class BExpressionContext
+public abstract class BExpressionContext implements IByteArrayUnifier
 {
   private  static final String CONTEXT_TAG = "---context:";
 	
@@ -70,6 +71,11 @@ public abstract class BExpressionContext
     return hashBucketVars[idx];
   }
 
+  protected final float getInverseBuildInVariable( int idx ) 
+  {
+    return arrayBuildInVariablesCache[currentHashBucket | 1][idx];
+  }
+
   private int linenr;
 
   public BExpressionMetaData meta;
@@ -98,7 +104,7 @@ public abstract class BExpressionContext
      // create the expression cache
      _arrayBitmap = new byte[hashSize][];
      _arrayCrc = new int[hashSize];
-     arrayBuildInVariablesCache = new float[hashSize][];
+     arrayBuildInVariablesCache = new float[hashSize << 1][];
   }
 
   /**
@@ -249,9 +255,14 @@ public abstract class BExpressionContext
     lookupDataFrozen = true;
   }
 
-  public void evaluate( int[] lookupData2 )
+  public final void evaluate( int[] lookupData2 )
   {
     lookupData = lookupData2;
+    evaluate();
+  }
+
+  private void evaluate()
+  {
     int n = expressionList.size();
     for( int expidx = 0; expidx < n; expidx++ )
     {
@@ -268,32 +279,62 @@ public abstract class BExpressionContext
     return "requests=" + requests + " requests2=" + requests2 + " cachemisses=" + cachemisses;
   }
 
+  @Override
+  public final byte[] unify( byte[] ab, int offset, int len )
+  {
+    int crc = Crc32.crc( ab, offset, len );
+    int hashSize = _arrayBitmap.length;
+    int idx = ( crc & 0xfffffff ) % hashSize;
+    byte[] abc = _arrayBitmap[idx];
+    if ( abc != null && abc.length == len )
+    {
+      int i = 0;
+      while (i < len)
+      {
+        if ( ab[offset + i] != abc[i] )
+          break;
+        i++;
+      }
+      if ( i == len )
+        return abc;
+    }
+    byte[] nab = new byte[len];
+    System.arraycopy( ab, offset, nab, 0, len );
+    return nab;
+  }
+
   /**
    * evaluates the data in the given byte array
    * 
    * @return true if the data is equivilant to the last calls data
    */
-  public void evaluate( boolean inverseDirection, byte[] ab )
+  public final void evaluate( boolean inverseDirection, byte[] ab )
   {
     requests++;
     lookupDataValid = false; // this is an assertion for a nasty pifall
 
     // calc hash bucket from crc
-    int crc = Crc32.crcWithInverseBit( ab, inverseDirection );
+    int crc = Crc32.crc( ab, 0, ab.length );
     int hashSize = _arrayBitmap.length;
-    currentHashBucket = ( crc & 0xfffffff ) % hashSize;
-    
-    int nBuildInVars = buildInVariableIdx.length;
-    hashBucketVars = arrayBuildInVariablesCache[currentHashBucket];
-    if ( hashBucketVars == null )
-    {
-      hashBucketVars = new float[nBuildInVars];
-      arrayBuildInVariablesCache[currentHashBucket] = hashBucketVars;
-    }
+    int hashBucket2 = ( crc & 0xfffffff ) % hashSize;
+    int hashBucket01 = hashBucket2 << 1;
+    int hashBucket02 = hashBucket01 | 1;
+    int hashBucket = inverseDirection ? hashBucket02 : hashBucket01;
 
-    if ( crc == _arrayCrc[currentHashBucket] )
+    if ( hashBucket != currentHashBucket )
     {
-      byte[] abBucket = _arrayBitmap[currentHashBucket];
+      currentHashBucket = hashBucket;
+      hashBucketVars = arrayBuildInVariablesCache[hashBucket];
+      if ( hashBucketVars == null )
+      {
+        arrayBuildInVariablesCache[hashBucket01] = new float[buildInVariableIdx.length];
+        arrayBuildInVariablesCache[hashBucket02] = new float[buildInVariableIdx.length];
+        hashBucketVars = arrayBuildInVariablesCache[hashBucket];
+      }
+    }
+    if ( crc == _arrayCrc[hashBucket2] )
+    {
+      byte[] abBucket = _arrayBitmap[hashBucket2];
       if ( ab == abBucket ) // fast identity check
       {
         return;
@@ -322,17 +363,31 @@ public abstract class BExpressionContext
     }
     cachemisses++;
 
-    _arrayBitmap[currentHashBucket] = ab;
-    _arrayCrc[currentHashBucket] = crc;
+    _arrayBitmap[hashBucket2] = ab;
+    _arrayCrc[hashBucket2] = crc;
 
-    decode( lookupData, inverseDirection, ab );
-    evaluate( lookupData );
+    int nBuildInVars = buildInVariableIdx.length;
 
+    // forward direction
+    decode( lookupData, false, ab );
+    evaluate();
+    float[] vars = arrayBuildInVariablesCache[hashBucket01];
     for ( int vi = 0; vi < nBuildInVars; vi++ )
     {
       int idx = buildInVariableIdx[vi];
-      hashBucketVars[vi] = idx == -1 ? 0.f : variableData[idx];
+      vars[vi] = idx == -1 ? 0.f : variableData[idx];
     }
+
+    // inverse direction
+    lookupData[0] = 2; // inverse shortcut: reuse decoding
+    evaluate();
+    vars = arrayBuildInVariablesCache[hashBucket02];
+    for ( int vi = 0; vi < nBuildInVars; vi++ )
+    {
+      int idx = buildInVariableIdx[vi];
+      vars[vi] = idx == -1 ? 0.f : variableData[idx];
+    }
+
   }
 
   public void dumpStatistics()
diff --git a/brouter-expressions/src/main/java/btools/expressions/BExpressionContextWay.java b/brouter-expressions/src/main/java/btools/expressions/BExpressionContextWay.java
index 4949352..0e4be14 100644
--- a/brouter-expressions/src/main/java/btools/expressions/BExpressionContextWay.java
+++ b/brouter-expressions/src/main/java/btools/expressions/BExpressionContextWay.java
@@ -32,6 +32,8 @@ public final class BExpressionContextWay extends BExpressionContext implements T
   public float getPriorityClassifier() { return getBuildInVariable(9); }
   public float getClassifierMask() { return getBuildInVariable(10); }
 
+  public float getInverseCostfactor() { return getInverseBuildInVariable(0); }
+
   public BExpressionContextWay( BExpressionMetaData meta )
   {
     super( "way", meta );
@@ -54,8 +56,7 @@ public final class BExpressionContextWay extends BExpressionContext implements T
     float minCostFactor = getCostfactor();
     if ( minCostFactor >= 9999.f )
     {
-      evaluate( true, description );
-      float reverseCostFactor = getCostfactor();
+      float reverseCostFactor = getInverseCostfactor();
       if ( reverseCostFactor < minCostFactor )
       {
         minCostFactor = reverseCostFactor;
diff --git a/brouter-mapaccess/src/main/java/btools/mapaccess/NodesCache.java b/brouter-mapaccess/src/main/java/btools/mapaccess/NodesCache.java
index f4be311..e0512b2 100644
--- a/brouter-mapaccess/src/main/java/btools/mapaccess/NodesCache.java
+++ b/brouter-mapaccess/src/main/java/btools/mapaccess/NodesCache.java
@@ -215,7 +215,7 @@ public final class NodesCache
     long id = node.getIdFromPos();
     if ( segment.getAndClear( id ) )
     {
-      node.parseNodeBody( segment, nodesMap );
+      node.parseNodeBody( segment, nodesMap, expCtxWay );
     }
 
     if ( garbageCollectionEnabled ) // garbage collection
diff --git a/brouter-mapaccess/src/main/java/btools/mapaccess/OsmNode.java b/brouter-mapaccess/src/main/java/btools/mapaccess/OsmNode.java
index 3224ab8..96bfb02 100644
--- a/brouter-mapaccess/src/main/java/btools/mapaccess/OsmNode.java
+++ b/brouter-mapaccess/src/main/java/btools/mapaccess/OsmNode.java
@@ -7,7 +7,9 @@ package btools.mapaccess;
 
 import btools.codec.MicroCache;
 import btools.codec.MicroCache2;
+import btools.expressions.BExpressionContextWay;
 import btools.util.ByteArrayUnifier;
+import btools.util.IByteArrayUnifier;
 
 public class OsmNode implements OsmPos
 {
@@ -45,22 +47,22 @@ public class OsmNode implements OsmPos
   public byte[] nodeDescription;
 
   // interface OsmPos
-  public int getILat()
+  public final int getILat()
   {
     return ilat;
   }
 
-  public int getILon()
+  public final int getILon()
   {
     return ilon;
   }
 
-  public short getSElev()
+  public final short getSElev()
   {
     return selev;
   }
 
-  public double getElev()
+  public final double getElev()
   {
     return selev / 4.;
   }
@@ -71,7 +73,7 @@ public class OsmNode implements OsmPos
   public OsmLink firstlink = null;
 
   // preliminry in forward order to avoid regressions
-  public void addLink( OsmLink link )
+  public final void addLink( OsmLink link )
   {
     if ( firstlink == null )
     {
@@ -117,7 +119,7 @@ public class OsmNode implements OsmPos
     return null;
   }
 
-  public int calcDistance( OsmPos p )
+  public final int calcDistance( OsmPos p )
   {
     double l = ( ilat - 90000000 ) * 0.00000001234134;
     double l2 = l * l;
@@ -135,17 +137,17 @@ public class OsmNode implements OsmPos
     return "" + getIdFromPos();
   }
 
-  public void parseNodeBody( MicroCache mc, OsmNodesMap hollowNodes )
+  public final void parseNodeBody( MicroCache mc, OsmNodesMap hollowNodes, IByteArrayUnifier expCtxWay )
   {
     if ( mc instanceof MicroCache2 )
     {
-      parseNodeBody2( (MicroCache2) mc, hollowNodes );
+      parseNodeBody2( (MicroCache2) mc, hollowNodes, expCtxWay );
     }
     else
       throw new IllegalArgumentException( "unknown cache version: " + mc.getClass() );
   }
 
-  public void parseNodeBody2( MicroCache2 mc, OsmNodesMap hollowNodes )
+  public final void parseNodeBody2( MicroCache2 mc, OsmNodesMap hollowNodes, IByteArrayUnifier expCtxWay )
   {
     ByteArrayUnifier abUnifier = hollowNodes.getByteArrayUnifier();
 
@@ -165,7 +167,7 @@ public class OsmNode implements OsmPos
       int descSize = sizecode >> 1;
       if ( descSize > 0 )
       {
-        description = mc.readUnified( descSize, abUnifier );
+        description = mc.readUnified( descSize, expCtxWay );
       }
       byte[] geometry = mc.readDataUntil( endPointer );
 
@@ -221,22 +223,22 @@ public class OsmNode implements OsmPos
   }
 
 
-  public boolean isHollow()
+  public final boolean isHollow()
   {
     return selev == -12345;
   }
 
-  public void setHollow()
+  public final void setHollow()
   {
     selev = -12345;
   }
 
-  public long getIdFromPos()
+  public final long getIdFromPos()
   {
     return ( (long) ilon ) << 32 | ilat;
   }
 
-  public void unlinkLink( OsmLink link )
+  public final void unlinkLink( OsmLink link )
   {
     if ( link == firstlink )
     {
@@ -254,7 +256,7 @@ public class OsmNode implements OsmPos
   }
 
   @Override
-  public boolean equals( Object o )
+  public final boolean equals( Object o )
   {
     if ( o instanceof OsmNode )
     {
@@ -265,7 +267,7 @@ public class OsmNode implements OsmPos
   }
 
   @Override
-  public int hashCode()
+  public final int hashCode()
   {
     return ilon + ilat;
   }
diff --git a/brouter-util/src/main/java/btools/util/ByteArrayUnifier.java b/brouter-util/src/main/java/btools/util/ByteArrayUnifier.java
index 97e9fc9..a9eb65f 100644
--- a/brouter-util/src/main/java/btools/util/ByteArrayUnifier.java
+++ b/brouter-util/src/main/java/btools/util/ByteArrayUnifier.java
@@ -1,6 +1,6 @@
 package btools.util;
 
-public final class ByteArrayUnifier
+public final class ByteArrayUnifier implements IByteArrayUnifier
 {
   private byte[][] byteArrayCache;
   private int[] crcCrosscheck;
diff --git a/brouter-util/src/main/java/btools/util/ByteDataReader.java b/brouter-util/src/main/java/btools/util/ByteDataReader.java
index ccacfab..ca51bdc 100644
--- a/brouter-util/src/main/java/btools/util/ByteDataReader.java
+++ b/brouter-util/src/main/java/btools/util/ByteDataReader.java
@@ -107,18 +107,44 @@ public class ByteDataReader
 	  return ( v & 1 ) == 0 ? v >> 1 : -(v >> 1 );
   }
 
+  public final int readVarLengthUnsigned_old()
+  {
+    int v = 0;
+    int shift = 0;
+    for ( ;; )
+    {
+      byte b = ab[aboffset++];
+      v |= ( ( b & 0x7f ) << shift );
+      if ( ( b & 0x80 ) == 0 )
+      {
+        break;
+      }
+      shift += 7;
+    }
+    return v;
+  }
+
   public final int readVarLengthUnsigned()
   {
-	int v = 0;
-	int shift = 0;
-	for(;;)
-	{
-	  int i7 = ab[aboffset++] & 0xff;
-	  v |= (( i7 & 0x7f ) << shift);
-	  if ( ( i7 & 0x80 ) == 0 ) break;
-	  shift += 7;
-	}
-	return v;
+    byte b;
+    int v = (b=ab[aboffset++]) & 0x7f;
+    if ( b >= 0 ) return v;
+    v |= ( (b=ab[aboffset++]) & 0x7f ) <<  7;
+    if ( b >= 0 ) return v;
+    v |= ( (b=ab[aboffset++]) & 0x7f ) << 14;
+    if ( b >= 0 ) return v;
+    v |= ( (b=ab[aboffset++]) & 0x7f ) << 21;
+    if ( b >= 0 ) return v;
+    v |= ( (b=ab[aboffset++]) & 0x7f ) << 28;
+    if ( b >= 0 ) return v;
+    v |= ( (b=ab[aboffset++]) & 0x7f ) << 35;
+    if ( b >= 0 ) return v;
+    v |= ( (b=ab[aboffset++]) & 0x7f ) << 42;
+    if ( b >= 0 ) return v;
+    v |= ( (b=ab[aboffset++]) & 0x7f ) << 49;
+    if ( b >= 0 ) return v;
+    v |= ( (b=ab[aboffset++]) & 0x7f ) << 56;
+    return v;
   }
 
   public final void readFully( byte[] ta )
diff --git a/brouter-util/src/main/java/btools/util/Crc32.java b/brouter-util/src/main/java/btools/util/Crc32.java
index 760b652..c815317 100644
--- a/brouter-util/src/main/java/btools/util/Crc32.java
+++ b/brouter-util/src/main/java/btools/util/Crc32.java
@@ -5,20 +5,8 @@ package btools.util;
  *
  * @author ab
  */
-public class Crc32
+public final class Crc32
 {
-  public static int crc( long bitmap )
-  {
-    int crc  = 0xFFFFFFFF;
-    long bm = bitmap;
-    for( int j=0; j<8; j++ )
-    {
-      crc = (crc >>> 8) ^ crctable[(crc ^ (int)bm) & 0xff];
-      bm >>= 8;
-    }
-    return crc;
-  }
-     
   public static int crc( byte[] ab, int offset, int len )
   {
     int crc  = 0xFFFFFFFF;
@@ -30,17 +18,6 @@ public class Crc32
     return crc;
   }
 
-  public static int crcWithInverseBit( byte[] ab, boolean isInverse )
-  {
-    int crc  = 0xFFFFFF ^ ( isInverse ? 0x990951ba : 0x706af48f ); // inverse is webbed into crc...
-    int end = ab.length;
-    for( int j=0; j<end; j++ )
-    {
-      crc = (crc >>> 8) ^ crctable[(crc ^ ab[j]) & 0xff];
-    }
-    return isInverse ? crc | 0x80000000 : crc & 0x7fffffff; // ... and set as high bit
-  }
-
   private static int[] crctable = {
           0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
           0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
diff --git a/brouter-util/src/main/java/btools/util/IByteArrayUnifier.java b/brouter-util/src/main/java/btools/util/IByteArrayUnifier.java
new file mode 100644
index 0000000..f441a36
--- /dev/null
+++ b/brouter-util/src/main/java/btools/util/IByteArrayUnifier.java
@@ -0,0 +1,6 @@
+package btools.util;
+
+public interface IByteArrayUnifier
+{
+  byte[] unify( byte[] ab, int offset, int len );
+}