Abstract
The main purpose of the study presented in this paper was to investigate the efficiency of traffic signs as described in the Vienna Convention as a mean to inform, warn and instructions to drivers. Primary hypothesis of the study were that some symbols and signs are ambiguous and that there exists signs that drivers misunderstand, perceive as confusing or even give an impression that actions are allowed that in fact is dangerous. Signs in use have been photographed. A great number of drivers were interviewed and questionnaires sent to drivers in several European and Arabic countries. The statistical analysis of the answers proves the correctness of the basic assumptions.