This doesn't even touch on the primary method for manufacturing hydrogen that is used in very small sections of the trucking industry so that they can pump enough hydrogen onto a truck to literally go maybe 300 miles. The procedure is so dirty, and so inefficient it actually takes a considerable percentage over a single gallon of what is called fossil fuels even though it never came from fossils in the first place, to manufacture 1 gallon of hydrogen Which is far far less efficient and effective than 1 gallon of gasoline or fuel oil. Making it many times dirtier than diesel alone. Diesel even without the EGR systems and particulate filters, is far cleaner because the vast majority of the soot that comes out of a diesel falls to the ground and becomes dirt.