code: @Pure
  	public BusStop getNearestBusStop(double x, double y) {
  		double distance = Double.POSITIVE_INFINITY;
  		BusStop bestStop = null;
  		double dist;
  
  		for (final BusStop stop : this.validBusStops) {
  			dist = stop.distance(x, y);
  			if (dist < distance) {
  				distance = dist;
  				bestStop = stop;
  			}
  		}
  
  		return bestStop;
  	}
docs: Replies the nearest bus stops to the given point.
  
  @param x x coordinate.
  @param y y coordinate.
  @return the nearest bus stop or <code>null</code> if none was found.