code: public static void setPreferredRoadConnectionDistance(double distance) {
  		final Preferences prefs = Preferences.userNodeForPackage(RoadNetworkConstants.class);
  		if (prefs != null) {
  			if (distance <= 0.) {
  				prefs.remove("ROAD_CONNECTION_DISTANCE"); //$NON-NLS-1$
  			} else {
  				prefs.putDouble("ROAD_CONNECTION_DISTANCE", distance); //$NON-NLS-1$
  			}
  		}
  	}
docs: Set the preferred distance below which roads may be connected.
  
  @param distance is the preferred distance (in meters) below which roads may be connected.