While the use of hydrogen in fuel cell vehicles will be the ultimate target for sustainable mobility, much attention has to be devoted to a suitable "bridge technology", to accelerate the process of the introduction of these new technologies and in the meantime to build an infrastructure suitable for the utilisation of hydrogen. In the short-medium term, the atmospheric emissions could be significantly reduced by using different percentages of hydrogen mixed with natural gas in internal combustion engines. The paper is based on the results of an experimental test campaign carried on in ENEA labs, aimed at identifying the prospective of the use of blends of natural gas and hydrogen (HCNG) in existing ICE vehicles. The tested vehicle is an IVECO Daily CNG, originally fuelled with natural gas and the tests had been made on the ECE15 driving cycle comparing the emission levels of the original configuration (CNG) with the results obtained with different blends (percentage of hydrogen in the fuel) and control strategies (stoichiometric or lean burn). (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.