diff --git a/StRoot/StBTofCalibMaker/StBTofCalibMaker.cxx b/StRoot/StBTofCalibMaker/StBTofCalibMaker.cxx
index afc052abba5..c82328a3523 100644
--- a/StRoot/StBTofCalibMaker/StBTofCalibMaker.cxx
+++ b/StRoot/StBTofCalibMaker/StBTofCalibMaker.cxx
@@ -2835,36 +2835,20 @@ void StBTofCalibMaker::writePPPAHistograms()
 //_____________________________________________________________________________
 float StBTofCalibMaker::tofCellResolution(const Int_t itray, const Int_t iModuleChan)
 {
+    float resolution(0.013); // 0.013 by default - 1/beta resolution
+    if (itray<0){return resolution;}
 
- float resolution(0.013); // 0.013 by default - 1/beta resolution
- if (itray<0){return resolution;}
-
- int module = iModuleChan/6 + 1;
- int cell   = iModuleChan%6 + 1;
- // mBTofRes::timeres_tof() reports in picoseconds
- float stop_resolution  = mBTofRes->timeres_tof(itray, module, cell)/1000.;
-
-float start_resolution(0);
- if (mUseVpdStart){
-
-   // For VPD timing determine the VPD starttime by combing the resolutions of
-   //   tray == 122 (east)
-   //   mSimParams[singleHit.tubeId-1+19].singleTubeRes
-   //   tray 121 (west)
-   //   mSimParams[singleHit.tubeId-1].singleTubeRes
-   //
-   // needs to be implemented
-
- }
- else {
-   // combine an average BTOF resolution based on NT0
-   // more sophisticated: figure out what BTOF cells actually went into the NT0 count.
-
-   // mBTofRes::timeres_tof() reports in picoseconds
-   start_resolution = mBTofRes->average_timeres_tof()/sqrt(mNTzero)/1000.;
- }
+    int module = iModuleChan/6 + 1;
+    int cell   = iModuleChan%6 + 1;
+    // mBTofRes::timeres_tof() reports in picoseconds
+    float stop_resolution  = mBTofRes->timeres_tof(itray, module, cell)/1000.;
 
- resolution = sqrt(stop_resolution*stop_resolution + start_resolution*start_resolution);
+    float start_resolution = 0.0;
+    if (mUseVpdStart)
+        start_resolution = mVpdResConfig->singleTubeRes(mVPDHitPatternEast, mVPDHitPatternWest)/1000.;
+    else
+        start_resolution = mBTofRes->average_timeres_tof()/sqrt(mNTzero)/1000.;
+    resolution = sqrt(stop_resolution*stop_resolution + start_resolution*start_resolution);
 
-return resolution;
+    return resolution;
 }
diff --git a/StRoot/StBTofUtil/StVpdSimConfig.h b/StRoot/StBTofUtil/StVpdSimConfig.h
index 26176a355bd..69d6ee0be95 100644
--- a/StRoot/StBTofUtil/StVpdSimConfig.h
+++ b/StRoot/StBTofUtil/StVpdSimConfig.h
@@ -29,21 +29,35 @@ class StVpdSimConfig : public StMaker {
     //! structure containing tube parameters
 	struct SingleTubeParams{
         float singleTubeRes;    //!< Resolution of a particular Vpd tube in ps
-        int tubeId;             //!< Tube Id (number) [0,37] with west Vpd [0,18] and east Vpd [19,37]
-        int tubeStatusFlag;     //!< Status flag for whether tube was active (1) or inactive (0)
-        int tubeTriggerFlag;    //!< Status flag for whether tube was triggered on (1) or not (0)
+        int tubeId,             //!< Tube Id (number) [0,37] with west Vpd [0,18] and east Vpd [19,37]
+            tubeStatusFlag,     //!< Status flag for whether tube was active (1) or inactive (0)
+            tubeTriggerFlag;    //!< Status flag for whether tube was triggered on (1) or not (0)
 	};
 
-/// calculate correct resolution based on those tubes that were used
-double singleTubeRes(UInt_t mVPDHitPatternEast, UInt_t mVPDHitPatternWest){
-	double vpdResSumSqr(0.), vpdresolution(0.);
-	for (int i=0; i<19; i++){
-		if (1 << i && mVPDHitPatternEast) vpdResSumSqr += (mSimParams[i].singleTubeRes)*(mSimParams[i].singleTubeRes);
-		if (1 << i && mVPDHitPatternWest) vpdResSumSqr += (mSimParams[i+19].singleTubeRes)*(mSimParams[i+19].singleTubeRes);
+	/**
+	 * @brief Calculate correct resolution based on those tubes that were used.
+	 * 
+	 * @param mVPDHitPatternEast 9 digit binary number specifying hit pattern of east VPD tubes.
+	 * @param mVPDHitPatternWest 9 digit binary number specifying hit pattern of west VPD tubes.
+	 * @return double vpd resolution.
+	 */
+	double singleTubeRes(UInt_t mVPDHitPatternEast, UInt_t mVPDHitPatternWest){
+		double vpdResSumSqr(0.),
+			   vpdresolution(0.);
+		int    total_vpd_hits = 0; //Total number of vpd tubes used.
+		for (int i=0; i<19; i++){
+			if (1 << i & mVPDHitPatternEast) {
+				vpdResSumSqr += (mSimParams[i].singleTubeRes)*(mSimParams[i].singleTubeRes);
+				total_vpd_hits += 1;
+			}
+			if (1 << i & mVPDHitPatternWest) {
+				vpdResSumSqr += (mSimParams[i+19].singleTubeRes)*(mSimParams[i+19].singleTubeRes);
+				total_vpd_hits += 1;
+			}
 		}
-  	vpdresolution = sqrt(vpdResSumSqr);
-	return vpdresolution;
-}
+		vpdresolution = sqrt(vpdResSumSqr)/total_vpd_hits;
+		return vpdresolution;
+	}
 
     /**
     * Calculates the average resolution across all 38 tubes (discounts inactive tubes)