Hyundai is hyping hydrogen, cruising cross-country in a fuel-cell Tucson to turn people on to the fuel of the future.

We’ve seen this before, from the likes of Daimler and Honda and even Toyota, all of whom firmly believe hydrogen will mend our fuelish ways. For all the love hybrids and battery electrics get these days, several leading automakers still say hydrogen is the best long-term play.

Hyundai’s been experimenting with hydrogen for more than a decade, and it is conducting a 4,500-mile tour through 15 states in the Tucson ix FCEV and to promote its advancements and advocacy of the...