diff --git a/DataFormats/TrackReco/interface/HitPattern.h b/DataFormats/TrackReco/interface/HitPattern.h
index fcdde25edc9c9..e23680ac23ec9 100644
--- a/DataFormats/TrackReco/interface/HitPattern.h
+++ b/DataFormats/TrackReco/interface/HitPattern.h
@@ -279,9 +279,20 @@ namespace reco {
     int numberOfInactiveHits() const;         // not-null, inactive
     int numberOfInactiveTrackerHits() const;  // not-null, inactive, tracker
 
-
-    int numberOfValidStripLayersWithMonoAndStereo () 
+    int numberOfValidStripLayersWithMonoAndStereo (uint32_t stripdet, uint32_t layer) 
       const; // count strip layers that have non-null, valid mono and stereo hits
+ 
+    int numberOfValidStripLayersWithMonoAndStereo () 
+      const {return numberOfValidStripLayersWithMonoAndStereo(0,0);}
+
+    int numberOfValidTOBLayersWithMonoAndStereo (uint32_t layer = 0) 
+      const {return numberOfValidStripLayersWithMonoAndStereo(StripSubdetector::TOB,layer);}
+    int numberOfValidTIBLayersWithMonoAndStereo (uint32_t layer = 0) 
+      const {return numberOfValidStripLayersWithMonoAndStereo(StripSubdetector::TIB,layer);}
+    int numberOfValidTIDLayersWithMonoAndStereo (uint32_t layer = 0) 
+      const {return numberOfValidStripLayersWithMonoAndStereo(StripSubdetector::TID,layer);}
+    int numberOfValidTECLayersWithMonoAndStereo (uint32_t layer = 0) 
+      const {return numberOfValidStripLayersWithMonoAndStereo(StripSubdetector::TEC,layer);} 
 
     uint32_t getTrackerLayerCase(uint32_t substr, uint32_t layer) const;
     uint32_t getTrackerMonoStereo (uint32_t substr, uint32_t layer) const;
diff --git a/DataFormats/TrackReco/src/HitPattern.cc b/DataFormats/TrackReco/src/HitPattern.cc
index 6edfba5c580ec..a0dcd74241960 100644
--- a/DataFormats/TrackReco/src/HitPattern.cc
+++ b/DataFormats/TrackReco/src/HitPattern.cc
@@ -220,8 +220,7 @@ int HitPattern::numberOfHits() const {
   return count;
 }
 
-
-int HitPattern::numberOfValidStripLayersWithMonoAndStereo () const {
+int HitPattern::numberOfValidStripLayersWithMonoAndStereo (uint32_t stripdet, uint32_t layer) const {
   static const int nHits = (PatternSize * 32) / HitSize;
   bool hasMono[SubstrMask + 1][LayerMask + 1];
   //     printf("sizeof(hasMono) = %d\n", sizeof(hasMono));
@@ -233,17 +232,19 @@ int HitPattern::numberOfValidStripLayersWithMonoAndStereo () const {
     uint32_t pattern = getHitPattern(i);
     if (pattern == 0) break;
     if (validHitFilter(pattern) && stripHitFilter(pattern)) {
+      if (stripdet!=0 && getSubStructure(pattern)!=stripdet) continue; 
+      if (layer!=0    && getSubSubStructure(pattern)!=layer) continue;
       switch (getSide(pattern)) {
       case 0: // mono
-	hasMono[getSubStructure(pattern)][getLayer(pattern)] 
-	  = true;
-	break;
+      hasMono[getSubStructure(pattern)][getLayer(pattern)] 
+        = true;
+      break;
       case 1: // stereo
-	hasStereo[getSubStructure(pattern)][getLayer(pattern)]
-	  = true;
-	break;
+      hasStereo[getSubStructure(pattern)][getLayer(pattern)]
+        = true;
+      break;
       default:
-	break;
+      break;
       }
     }
     
@@ -253,7 +254,7 @@ int HitPattern::numberOfValidStripLayersWithMonoAndStereo () const {
   for (int i = 0; i < SubstrMask + 1; ++i) 
     for (int j = 0; j < LayerMask + 1; ++j)
       if (hasMono[i][j] && hasStereo[i][j])
-	count++;
+      count++;
   return count;
 }