I always liked the fact that UPS experimented with various fuel sources, gasoline, diesel, electric, natural gas, etc. I do however have reservations about fuel cell technology and its use for passenger vehicles. There is no doubt that this is the cleanest source of power for vehicles. What no one is talking about is the danger involved. Hydrogen (the fuel used) is extremely flammable. Note the Hindenberg disaster that all but ended the "lighter than air" flying vehicles. The dispensing of hydrogen in small quantities as an auto (package car) fuel can be extremely dangerous. One bad connection during fueling and a tiny spark (even from static electric) could blow up the fueler, the vehicle and in the worst case the building(s) nearby.
Anyone out there with any experience or expertise to agree or disagree?