diff --git a/jsprit-core/src/main/java/jsprit/core/problem/solution/route/activity/TimeWindowsImpl.java b/jsprit-core/src/main/java/jsprit/core/problem/solution/route/activity/TimeWindowsImpl.java
index 67580bac..e449004f 100644
--- a/jsprit-core/src/main/java/jsprit/core/problem/solution/route/activity/TimeWindowsImpl.java
+++ b/jsprit-core/src/main/java/jsprit/core/problem/solution/route/activity/TimeWindowsImpl.java
@@ -19,6 +19,9 @@ public class TimeWindowsImpl implements TimeWindows {
             if(timeWindow.getEnd() > tw.getStart() && timeWindow.getEnd() < tw.getEnd()){
                 throw new IllegalStateException("time-windows cannot overlap each other. overlap: " + tw + ", " + timeWindow);
             }
+            if(timeWindow.getStart() <= tw.getStart() && timeWindow.getEnd() >= tw.getEnd()){
+                throw new IllegalStateException("time-windows cannot overlap each other. overlap: " + tw + ", " + timeWindow);
+            }
         }
         timeWindows.add(timeWindow);
     }
diff --git a/jsprit-core/src/test/java/jsprit/core/problem/solution/route/activity/TimeWindowsImplTest.java b/jsprit-core/src/test/java/jsprit/core/problem/solution/route/activity/TimeWindowsImplTest.java
index ddf7af60..24b08b0d 100644
--- a/jsprit-core/src/test/java/jsprit/core/problem/solution/route/activity/TimeWindowsImplTest.java
+++ b/jsprit-core/src/test/java/jsprit/core/problem/solution/route/activity/TimeWindowsImplTest.java
@@ -20,4 +20,11 @@ public class TimeWindowsImplTest {
         tws.add(TimeWindow.newInstance(50, 100));
         tws.add(TimeWindow.newInstance(40,150));
     }
+
+    @Test(expected = IllegalStateException.class)
+    public void overlappingTW3_shouldThrowException(){
+        TimeWindowsImpl tws = new TimeWindowsImpl();
+        tws.add(TimeWindow.newInstance(50, 100));
+        tws.add(TimeWindow.newInstance(50, 100));
+    }
 }