During research of new possible sources of energy, hydrogen was identified as a very promising potential energy carrier. Because of its very good energy characteristics, it has received a lot of research attention while its safety features are the ones that were its drawback for potential use. Before it can be put in general use in transportation industry, there were safety problems identified as hazard which has to be further analysed. The main problem in the transport is the safe use of hydrogen in road tunnels where it should be safe in case of possible accidents where its release could end up in fire, deflagration and even detonation. In the article, concept of hydrogen trap on the ceiling is developed and described based on the available data and research results from which passive safety approach is suggested to be used in future designs of the road tunnels. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.