--- a/python/events.py	Mon Jun 29 16:15:04 2015 -0400
+++ b/python/events.py	Mon Jun 29 23:09:58 2015 -0400
@@ -217,7 +217,8 @@
         self.collisionPoints, crossingZones = predictionParameters.computeCrossingsCollisions(self.roadUser1, self.roadUser2, collisionDistanceThreshold, timeHorizon, computeCZ, debug, commonTimeInterval, nProcesses,usePrototypes,route1,route2,prototypes,secondStepPrototypes,nMatching,objects,noiseEntryNums,noiseExitNums,minSimilarity,mostMatched,useDestination,useSpeedPrototype,acceptPartialLength, step)
         for i, cp in self.collisionPoints.iteritems():
             TTCs[i] = prediction.SafetyPoint.computeExpectedIndicator(cp)
-        self.addIndicator(indicators.SeverityIndicator(Interaction.indicatorNames[7], TTCs, mostSevereIsMax=False))
+        if len(TTCs) > 0:
+            self.addIndicator(indicators.SeverityIndicator(Interaction.indicatorNames[7], TTCs, mostSevereIsMax=False))
         
         # crossing zones and pPET
         if computeCZ: