diff --git a/brouter-core/src/main/java/btools/router/RoutingEngine.java b/brouter-core/src/main/java/btools/router/RoutingEngine.java
index 4b887bb..ba497d2 100644
--- a/brouter-core/src/main/java/btools/router/RoutingEngine.java
+++ b/brouter-core/src/main/java/btools/router/RoutingEngine.java
@@ -782,7 +782,7 @@ public class RoutingEngine extends Thread
       addToOpenset( startPath1 );
       addToOpenset( startPath2 );
     }
-    ArrayList<OsmPath> openBorderList = new ArrayList<OsmPath>();
+    ArrayList<OsmPath> openBorderList = new ArrayList<OsmPath>(4096);
     boolean memoryPanicMode = false;
     boolean needNonPanicProcessing = false;
     
@@ -793,8 +793,6 @@ public class RoutingEngine extends Thread
         throw new IllegalArgumentException( "operation killed by thread-priority-watchdog after " + ( System.currentTimeMillis() - startTime)/1000 + " seconds" );
       }
       
-      
-      
       if ( maxRunningTime > 0 )
       {
         long timeout = ( matchPath == null && fastPartialRecalc ) ? maxRunningTime/3 : maxRunningTime;
@@ -803,11 +801,11 @@ public class RoutingEngine extends Thread
           throw new IllegalArgumentException( operationName + " timeout after " + (timeout/1000) + " seconds" );
         }
       }
-      OsmPath path = null;
 
-      synchronized( openSet )
-      {
-        path = openSet.popLowestKeyValue();
+     synchronized( openSet )
+     {
+
+        OsmPath path = openSet.popLowestKeyValue();
         if ( path == null )
         {
           if ( openBorderList.isEmpty() )
@@ -823,7 +821,6 @@ public class RoutingEngine extends Thread
           needNonPanicProcessing = true;
           continue;
         }
-      }
 
       if ( path.airdistance == -1 )
       {
@@ -835,14 +832,13 @@ public class RoutingEngine extends Thread
       {
         if ( !memoryPanicMode )
         {
-          if ( !nodesCache.nodesMap.isInMemoryBounds( openSet.getSize() ) )
+          if ( !nodesCache.nodesMap.isInMemoryBounds( openSet.getSize(), false ) )
           {
+// System.out.println( "collecting..." );
             int nodesBefore = nodesCache.nodesMap.nodesCreated;
             int pathsBefore = openSet.getSize();
             
             nodesCache.nodesMap.collectOutreachers();
-            synchronized( openSet )
-            {
               for(;;)
               {
                 OsmPath p3 = openSet.popLowestKeyValue();
@@ -852,14 +848,14 @@ public class RoutingEngine extends Thread
                   openBorderList.add( p3 );
                 }
               }
+              nodesCache.nodesMap.clearTemp();
               for( OsmPath p : openBorderList )
               {
                 openSet.add( p.cost + (int)(p.airdistance*airDistanceCostFactor), p );
               }
-            }
             openBorderList.clear();
             logInfo( "collected, nodes/paths before=" + nodesBefore + "/" + pathsBefore + " after=" + nodesCache.nodesMap.nodesCreated + "/" + openSet.getSize() + " maxTotalCost=" + maxTotalCost );
-            if ( !nodesCache.nodesMap.isInMemoryBounds( openSet.getSize()) ) // TODO
+            if ( !nodesCache.nodesMap.isInMemoryBounds( openSet.getSize(), true ) )
             {
               if ( maxTotalCost < 1000000000 || needNonPanicProcessing || fastPartialRecalc )
               {
@@ -1133,16 +1129,14 @@ public class RoutingEngine extends Thread
               }
               bestPath.treedepth = path.treedepth + 1;
               link.addLinkHolder( bestPath, currentNode );
-              synchronized( openSet )
-              {
-                addToOpenset( bestPath );
-              }
+              addToOpenset( bestPath );
             }
           }
         }
       }
             
       path.unregisterUpTree( routingContext );
+     }
     }
     
     if ( nodesVisited < MAXNODES_ISLAND_CHECK && islandNodePairs.getFreezeCount() < 5 )
diff --git a/brouter-mapaccess/src/main/java/btools/mapaccess/OsmNodesMap.java b/brouter-mapaccess/src/main/java/btools/mapaccess/OsmNodesMap.java
index 4a9360f..4ffb103 100644
--- a/brouter-mapaccess/src/main/java/btools/mapaccess/OsmNodesMap.java
+++ b/brouter-mapaccess/src/main/java/btools/mapaccess/OsmNodesMap.java
@@ -21,6 +21,7 @@ public final class OsmNodesMap
   
   public int nodesCreated;
   public long maxmem;  
+  private long currentmaxmem = 4000000; // start with 4 MB
   public int lastVisitID = 1000;
   public int baseID = 1000;
   
@@ -127,11 +128,27 @@ public final class OsmNodesMap
       
 
   
-  public boolean isInMemoryBounds( int npaths )
+  public boolean isInMemoryBounds( int npaths, boolean extend )
   {
 //    long total = nodesCreated * 76L + linksCreated * 48L;
     long total = nodesCreated * 95L + npaths * 200L;
-    return total <= maxmem;
+    
+    if ( extend )
+    {
+      total += 100000;
+    
+      // when extending, try to have 1 MB  space
+      long delta = total + 1900000 - currentmaxmem;
+      if ( delta > 0 )
+      {
+        currentmaxmem += delta;
+        if ( currentmaxmem > maxmem )
+        {
+          currentmaxmem = maxmem;
+        }
+      }
+    }
+    return total <= currentmaxmem;
   }
 
   private void addActiveNode( ArrayList<OsmNode> nodes2check, OsmNode n )
@@ -147,7 +164,7 @@ public final class OsmNodesMap
   {
     boolean sawLowIDs = false;
     lastVisitID++;
-    ArrayList<OsmNode> nodes2check = new ArrayList<OsmNode>();
+    nodes2check.clear();
     nodes2check.add( n0 );
     while ( !nodes2check.isEmpty() )
     {
@@ -191,12 +208,18 @@ public final class OsmNodesMap
 
     return false;
   }
+
+  private  ArrayList<OsmNode> nodes2check;
   
+  public void clearTemp()
+  {
+    nodes2check = null;
+  }
+
   public void collectOutreachers()
   {
+    nodes2check = new ArrayList<OsmNode>(nodesCreated);
     nodesCreated=0;
-  
-    ArrayList<OsmNode> nodes2check = new ArrayList<OsmNode>();
     for( OsmNode n : hmap.values() )
     {
       addActiveNode( nodes2check, n );
diff --git a/brouter-server/src/main/java/btools/server/BRouter.java b/brouter-server/src/main/java/btools/server/BRouter.java
index 33a96b3..299f361 100644
--- a/brouter-server/src/main/java/btools/server/BRouter.java
+++ b/brouter-server/src/main/java/btools/server/BRouter.java
@@ -127,7 +127,6 @@ public class BRouter
     {
       wplist.add( readPosition( args, 3, "to" ) );
       RoutingContext rc = readRoutingContext(args);
-      rc.memoryclass = 16;
       re = new RoutingEngine( "mytrack", "mylog", args[0], wplist, rc );
       re.doRun( 0 );