diff --git a/jsprit-core/src/main/java/jsprit/core/algorithm/box/Jsprit.java b/jsprit-core/src/main/java/jsprit/core/algorithm/box/Jsprit.java
index 037e7b38..45653c9c 100644
--- a/jsprit-core/src/main/java/jsprit/core/algorithm/box/Jsprit.java
+++ b/jsprit-core/src/main/java/jsprit/core/algorithm/box/Jsprit.java
@@ -96,6 +96,7 @@ public class Jsprit {
         INSERTION_NOISE_PROB("insertion.noise_prob"),
         RUIN_WORST_NOISE_LEVEL("worst.noise_level"),
         RUIN_WORST_NOISE_PROB("worst.noise_prob"),
+        FAST_REGRET("regret.fast"),
         CONSTRUCTION("construction");
 
         String paraName;
@@ -182,6 +183,7 @@ public class Jsprit {
             defaults.put(Parameter.RUIN_WORST_NOISE_LEVEL.toString(), String.valueOf(0.15));
             defaults.put(Parameter.RUIN_WORST_NOISE_PROB.toString(), String.valueOf(0.2));
             defaults.put(Parameter.VEHICLE_SWITCH.toString(), String.valueOf(true));
+            defaults.put(Parameter.FAST_REGRET, String.valueOf(false));
             defaults.put(Parameter.CONSTRUCTION.toString(), Construction.REGRET_INSERTION.toString());
             return defaults;
         }
@@ -406,27 +408,57 @@ public class Jsprit {
         AbstractInsertionStrategy regret;
         final DefaultScorer scorer;
 
+        boolean fastRegret = Boolean.parseBoolean(getProperty(Parameter.FAST_REGRET.toString()));
         if (es != null) {
-            RegretInsertionConcurrent regretInsertion = (RegretInsertionConcurrent) new InsertionBuilder(vrp, fm, stateManager, constraintManager)
-                .setInsertionStrategy(InsertionBuilder.Strategy.REGRET)
-                .setConcurrentMode(es, noThreads)
-                .considerFixedCosts(toDouble(getProperty(Parameter.FIXED_COST_PARAM.toString())))
-                .setAllowVehicleSwitch(toBoolean(getProperty(Parameter.VEHICLE_SWITCH.toString())))
-                .setActivityInsertionCostCalculator(activityInsertion)
-                .build();
-            scorer = getRegretScorer(vrp);
-            regretInsertion.setScoringFunction(scorer);
-            regret = regretInsertion;
+            if(fastRegret){
+                RegretInsertionConcurrentFast regretInsertion = (RegretInsertionConcurrentFast) new InsertionBuilder(vrp, fm, stateManager, constraintManager)
+                    .setInsertionStrategy(InsertionBuilder.Strategy.REGRET)
+                    .setConcurrentMode(es, noThreads)
+                    .setFastRegret(true)
+                    .considerFixedCosts(toDouble(getProperty(Parameter.FIXED_COST_PARAM.toString())))
+                    .setAllowVehicleSwitch(toBoolean(getProperty(Parameter.VEHICLE_SWITCH.toString())))
+                    .setActivityInsertionCostCalculator(activityInsertion)
+                    .build();
+                scorer = getRegretScorer(vrp);
+                regretInsertion.setScoringFunction(scorer);
+                regret = regretInsertion;
+            }
+            else {
+                RegretInsertionConcurrent regretInsertion = (RegretInsertionConcurrent) new InsertionBuilder(vrp, fm, stateManager, constraintManager)
+                    .setInsertionStrategy(InsertionBuilder.Strategy.REGRET)
+                    .setConcurrentMode(es, noThreads)
+                    .considerFixedCosts(toDouble(getProperty(Parameter.FIXED_COST_PARAM.toString())))
+                    .setAllowVehicleSwitch(toBoolean(getProperty(Parameter.VEHICLE_SWITCH.toString())))
+                    .setActivityInsertionCostCalculator(activityInsertion)
+                    .build();
+                scorer = getRegretScorer(vrp);
+                regretInsertion.setScoringFunction(scorer);
+                regret = regretInsertion;
+            }
         } else {
-            RegretInsertion regretInsertion = (RegretInsertion) new InsertionBuilder(vrp, fm, stateManager, constraintManager)
-                .setInsertionStrategy(InsertionBuilder.Strategy.REGRET)
-                .setAllowVehicleSwitch(toBoolean(getProperty(Parameter.VEHICLE_SWITCH.toString())))
-                .considerFixedCosts(toDouble(getProperty(Parameter.FIXED_COST_PARAM.toString())))
-                .setActivityInsertionCostCalculator(activityInsertion)
-                .build();
-            scorer = getRegretScorer(vrp);
-            regretInsertion.setScoringFunction(scorer);
-            regret = regretInsertion;
+            if(fastRegret) {
+                RegretInsertionFast regretInsertion = (RegretInsertionFast) new InsertionBuilder(vrp, fm, stateManager, constraintManager)
+                    .setInsertionStrategy(InsertionBuilder.Strategy.REGRET)
+                    .setFastRegret(true)
+                    .setAllowVehicleSwitch(toBoolean(getProperty(Parameter.VEHICLE_SWITCH.toString())))
+                    .considerFixedCosts(toDouble(getProperty(Parameter.FIXED_COST_PARAM.toString())))
+                    .setActivityInsertionCostCalculator(activityInsertion)
+                    .build();
+                scorer = getRegretScorer(vrp);
+                regretInsertion.setScoringFunction(scorer);
+                regret = regretInsertion;
+            }
+            else{
+                RegretInsertion regretInsertion = (RegretInsertion) new InsertionBuilder(vrp, fm, stateManager, constraintManager)
+                    .setInsertionStrategy(InsertionBuilder.Strategy.REGRET)
+                    .setAllowVehicleSwitch(toBoolean(getProperty(Parameter.VEHICLE_SWITCH.toString())))
+                    .considerFixedCosts(toDouble(getProperty(Parameter.FIXED_COST_PARAM.toString())))
+                    .setActivityInsertionCostCalculator(activityInsertion)
+                    .build();
+                scorer = getRegretScorer(vrp);
+                regretInsertion.setScoringFunction(scorer);
+                regret = regretInsertion;
+            }
         }
         regret.setRandom(random);
 
diff --git a/jsprit-core/src/main/java/jsprit/core/algorithm/recreate/InsertionBuilder.java b/jsprit-core/src/main/java/jsprit/core/algorithm/recreate/InsertionBuilder.java
index 8b44f774..e3ada608 100644
--- a/jsprit-core/src/main/java/jsprit/core/algorithm/recreate/InsertionBuilder.java
+++ b/jsprit-core/src/main/java/jsprit/core/algorithm/recreate/InsertionBuilder.java
@@ -30,6 +30,9 @@ import java.util.concurrent.ExecutorService;
 
 public class InsertionBuilder {
 
+    private boolean fastRegret;
+
+
     public enum Strategy {
         REGRET, BEST
     }
@@ -70,6 +73,8 @@ public class InsertionBuilder {
 
     private Strategy strategy = Strategy.BEST;
 
+    private boolean isFastRegret = false;
+
     public InsertionBuilder(VehicleRoutingProblem vrp, VehicleFleetManager vehicleFleetManager, StateManager stateManager, ConstraintManager constraintManager) {
         super();
         this.vrp = vrp;
@@ -98,6 +103,12 @@ public class InsertionBuilder {
         return this;
     }
 
+    public InsertionBuilder setFastRegret(boolean fastRegret) {
+        this.isFastRegret = fastRegret;
+        return this;
+    }
+
+
     public InsertionBuilder setLocalLevel() {
         local = true;
         return this;
@@ -166,14 +177,27 @@ public class InsertionBuilder {
             }
         } else if (strategy.equals(Strategy.REGRET)) {
             if (executor == null) {
-                RegretInsertion regret = new RegretInsertion(costCalculator, vrp);
-//                regret.setSwitchAllowed(allowVehicleSwitch);
-                insertion = regret;
+                if(isFastRegret){
+                    RegretInsertionFast regret = new RegretInsertionFast(costCalculator, vrp, fleetManager);
+                    regret.setSwitchAllowed(allowVehicleSwitch);
+                    insertion = regret;
+                }
+                else {
+                    RegretInsertion regret = new RegretInsertion(costCalculator, vrp);
+                    insertion = regret;
+                }
 
             } else {
-                RegretInsertionConcurrent regret = new RegretInsertionConcurrent(costCalculator, vrp, executor);
-//                regret.setSwitchAllowed(allowVehicleSwitch);
-                insertion = regret;
+                if(isFastRegret){
+                    RegretInsertionConcurrentFast regret = new RegretInsertionConcurrentFast(costCalculator, vrp, executor, fleetManager);
+                    regret.setSwitchAllowed(allowVehicleSwitch);
+                    insertion = regret;
+                }
+                else{
+                    RegretInsertionConcurrent regret = new RegretInsertionConcurrent(costCalculator, vrp, executor);
+                    insertion = regret;
+                }
+
             }
         } else throw new IllegalStateException("you should never get here");
         for (InsertionListener l : iListeners) insertion.addListener(l);
diff --git a/jsprit-core/src/test/java/jsprit/core/algorithm/Solomon_IT.java b/jsprit-core/src/test/java/jsprit/core/algorithm/Solomon_IT.java
index ff5a5b86..39b24daa 100644
--- a/jsprit-core/src/test/java/jsprit/core/algorithm/Solomon_IT.java
+++ b/jsprit-core/src/test/java/jsprit/core/algorithm/Solomon_IT.java
@@ -25,9 +25,12 @@ public class Solomon_IT {
         new VrpXMLReader(vrpBuilder).read("src/test/resources/solomon_c101.xml");
         VehicleRoutingProblem vrp = vrpBuilder.build();
 
-        VehicleRoutingAlgorithm vra = Jsprit.createAlgorithm(vrp);
+        VehicleRoutingAlgorithm vra = Jsprit.Builder.newInstance(vrp)
+//            .setProperty(Jsprit.Parameter.THREADS,"3")
+//            .setProperty(Jsprit.Parameter.FAST_REGRET,"true")
+            .buildAlgorithm();
 //            VehicleRoutingAlgorithms.readAndCreateAlgorithm(vrp, "src/test/resources/algorithmConfig.xml");
-        vra.setMaxIterations(500);
+        vra.setMaxIterations(2000);
         Collection<VehicleRoutingProblemSolution> solutions = vra.searchSolutions();
         assertEquals(828.94, Solutions.bestOf(solutions).getCost(), 0.01);
     }
diff --git a/jsprit-core/src/test/resources/infiniteWriterV2Test.xml b/jsprit-core/src/test/resources/infiniteWriterV2Test.xml
index 07c5406a..2d9058ab 100644
--- a/jsprit-core/src/test/resources/infiniteWriterV2Test.xml
+++ b/jsprit-core/src/test/resources/infiniteWriterV2Test.xml
@@ -2,24 +2,9 @@
 <problem xmlns="http://www.w3schools.com"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3schools.com vrp_xml_schema.xsd">
      <problemType>
-          <fleetSize>FINITE</fleetSize>
+          <fleetSize>INFINITE</fleetSize>
      </problemType>
      <vehicles>
-          <vehicle>
-               <id>v2</id>
-               <typeId>vehType2</typeId>
-               <startLocation>
-                    <id>loc</id>
-               </startLocation>
-               <endLocation>
-                    <id>loc</id>
-               </endLocation>
-               <timeSchedule>
-                    <start>0.0</start>
-                    <end>1.7976931348623157E308</end>
-               </timeSchedule>
-               <returnToDepot>true</returnToDepot>
-          </vehicle>
           <vehicle>
                <id>v1</id>
                <typeId>vehType</typeId>
@@ -48,16 +33,58 @@
                     <time>0.0</time>
                </costs>
           </type>
-          <type>
-               <id>vehType2</id>
-               <capacity-dimensions>
-                    <dimension index="0">200</dimension>
-               </capacity-dimensions>
-               <costs>
-                    <fixed>0.0</fixed>
-                    <distance>1.0</distance>
-                    <time>0.0</time>
-               </costs>
-          </type>
      </vehicleTypes>
+     <services>
+          <service id="1" type="service">
+               <location>
+                    <id>loc</id>
+               </location>
+               <capacity-dimensions>
+                    <dimension index="0">1</dimension>
+               </capacity-dimensions>
+               <duration>2.0</duration>
+               <timeWindows>
+                    <timeWindow>
+                         <start>0.0</start>
+                         <end>1.7976931348623157E308</end>
+                    </timeWindow>
+               </timeWindows>
+          </service>
+          <service id="2" type="service">
+               <location>
+                    <id>loc2</id>
+               </location>
+               <capacity-dimensions>
+                    <dimension index="0">1</dimension>
+               </capacity-dimensions>
+               <duration>4.0</duration>
+               <timeWindows>
+                    <timeWindow>
+                         <start>0.0</start>
+                         <end>1.7976931348623157E308</end>
+                    </timeWindow>
+               </timeWindows>
+          </service>
+     </services>
+     <solutions>
+          <solution>
+               <cost>10.0</cost>
+               <routes>
+                    <route>
+                         <driverId>noDriver</driverId>
+                         <vehicleId>v1</vehicleId>
+                         <start>0.0</start>
+                         <act type="service">
+                              <serviceId>1</serviceId>
+                              <arrTime>0.0</arrTime>
+                              <endTime>0.0</endTime>
+                         </act>
+                         <end>0.0</end>
+                    </route>
+               </routes>
+               <unassignedJobs>
+                    <job id="2"/>
+               </unassignedJobs>
+          </solution>
+     </solutions>
 </problem>