Hydrogen seems to provide a panacea for our transport fuel problems, as it is an extremely common element and when used as a fuel gives zero carbon emissions. However, although hydrogen is common, it has to be extracted from compounds such as water or natural gas - and this extraction process uses lots of energy.
In CAT's Zero Carbon Britain report we see battery electric vehicles as a better choice than hydrogen vehicles, since making hydrogen by electrolysis of water uses lots of electricity. There are some instances where the superior energy storage properties of hydrogen are useful - such as in some buses and heavy goods vehicles. See the report for much more detail.