/** Clears any vehicle markers from the map */
 public synchronized void clear() {
   if (mMarkerData != null) {
     mMarkerData.clear();
     mMarkerData = null;
   }
   if (mCustomInfoWindowAdapter != null) {
     mCustomInfoWindowAdapter.clear();
   }
 }
 /**
  * Clears any stop markers from the map
  *
  * @param clearFocusedStop true to clear the currently focused stop, false to leave it on map
  */
 public synchronized void clear(boolean clearFocusedStop) {
   if (mMarkerData != null) {
     mMarkerData.clear(clearFocusedStop);
   }
 }