I can't believe companies are still investing in hydrogen cars. It is a dead end. There is no future. Everyone with a brain has known this for at least a decade, since the massive rise of batteries to power consumer electronics. Didn't BMW waste enough money on their gasoline/hydrogen internal combustion 7er from about a decade ago?
The problem with hydrogen cars is that you have to get hydrogen. 90%+ plus of the hydrogen we currently used is reformed from natural gas or methane. The reformation process produces just as many greenhouse gases from a volume of natural gas as burning it in an internal combustion engine would. Then why the hell do we deal with hydrogen at all? Well the theory is that the reformation process from natural gas or methane to hydrogen is about 80% efficient and then good fuel cells are about 80% efficient at producing electrical current from the given input of hydrogen, and then a brushless electric motor is about 90% efficient and so their combined ~58% efficiency is much better than an internal combustion engines ~30% efficiency of turning hydrocarbons (natural gas, for example) into mechanical energy.
However, internal combustion engines are a mature 100+ year old technology while high performance fuel cells still cost hundreds of thousands of dollars each and still require ultra-rare materials (platinum) to serve as catalysts.
Battery technologies are much more promising than hydrogen.