public void setAlphaRoad(int pos) throws InfraException {
if (pos > 3 || pos < 0) throw new InfraException("Position out of range");
if (allRoads[pos] == null) throw new InfraException("No road is conencted at position " + pos);
alphaRoads = (Road[]) Arrayutils.addElementUnique(alphaRoads, allRoads[pos]);
updateLanes();
}
