@Override
 public void handleEvent(ActivityStartEvent event) {
   CarrierAgent carrierAgent = getCarrierAgent(event.getPersonId());
   if (carrierAgent == null) return;
   carrierAgent.handleEvent(event);
 }
 @Override
 public void handleEvent(PersonDepartureEvent event) {
   CarrierAgent carrierAgent = getCarrierAgent(event.getPersonId());
   if (carrierAgent == null) return;
   carrierAgent.handleEvent(event);
 }
 @Override
 public void handleEvent(LinkEnterEvent event) {
   CarrierAgent carrierAgent = getCarrierAgent(event.getDriverId());
   if (carrierAgent == null) return;
   carrierAgent.handleEvent(event);
 }