"Hydrogen and ethanol for transportation use isn't as practical."
The best way to transport hydrogen is in - a hydrocarbon like gasoline. Safer, higher density, liquid so low pressure. The energy balance on ethanol is horrible.
CA does not allow the sale of any new diesel autos..so I guess this is only available to the select few who illegaly import them or buy used cars out of state.
CA blocks diesels due to the soot causing cancer.
Until that issue is cleared up..no more new diesels for CA.