diff --git a/jsprit-core/src/main/java/jsprit/core/problem/cost/VehicleRoutingActivityCosts.java b/jsprit-core/src/main/java/jsprit/core/problem/cost/VehicleRoutingActivityCosts.java
index ec9ea858..812ed19b 100644
--- a/jsprit-core/src/main/java/jsprit/core/problem/cost/VehicleRoutingActivityCosts.java
+++ b/jsprit-core/src/main/java/jsprit/core/problem/cost/VehicleRoutingActivityCosts.java
@@ -58,5 +58,6 @@ public interface VehicleRoutingActivityCosts {
      */
     public double getActivityCost(TourActivity tourAct, double arrivalTime, Driver driver, Vehicle vehicle);
 
+    public double getActivityDuration(TourActivity tourAct, double arrivalTime, Driver driver, Vehicle vehicle);
 
 }
diff --git a/jsprit-core/src/main/java/jsprit/core/problem/cost/WaitingTimeCosts.java b/jsprit-core/src/main/java/jsprit/core/problem/cost/WaitingTimeCosts.java
index 73b9a35a..183aafc5 100644
--- a/jsprit-core/src/main/java/jsprit/core/problem/cost/WaitingTimeCosts.java
+++ b/jsprit-core/src/main/java/jsprit/core/problem/cost/WaitingTimeCosts.java
@@ -19,4 +19,9 @@ public class WaitingTimeCosts implements VehicleRoutingActivityCosts {
         return 0;
     }
 
+    @Override
+    public double getActivityDuration(TourActivity tourAct, double arrivalTime, Driver driver, Vehicle vehicle) {
+        return tourAct.getOperationTime();
+    }
+
 }