private void updateStopHistory() {
		ArrayList<StopAdapter> stops = GTFS.getCurrentStopWindow();
		LinkedList<StopAdapter> closest = calcClosestStops();
		if (closest != null) {
			if (mStopHistoryIndex == -1) {
				mStopHistory.set(0, closest);
				mStopHistoryIndex = 0;
			} else {
				boolean duplicate = false;
				for (int i = 0; i < COORD_BUFFER_SIZE; i++) {
					if (closest.hashCode() == mStopHistory.get(
							mStopHistoryIndex).hashCode()) {
						duplicate = true;
						break;
					}
				}
				if (!duplicate) {
					mStopHistoryIndex = incIndex(mStopHistoryIndex);
					mStopHistory.set(mStopHistoryIndex, closest);
					findProbableRoutes();
				}
			}
		}
	}