Abstract
After the introduction and a general discussion on information processing, the information requirements on three distinct levels of decision making is discussed and from this the functional requirements for the information carriers are derived. This leads to a rather general discussion of the technologies involved. The paper ends with two chapters on specific information carriers, viz. vehicle signalling systems and road markings. This is done in order to emphasise the fact that those two information carriers are related simultaneously to at least two of the levels of decision making.