Market penetration models are presented, illustrating that direct hydr
ogen fuel cell vehicles could eventually provide industry with substan
tial return on investment without government subsidy, while at the sam
e time significantly reducing environmental degradation and oil import
s. This marker penetration model estimates the likely number of fuel c
ell vehicles that might be sold in the United States over the next thr
ee decades, based on the projected costs of these vehicles and the cos
t of hydrogen compared to other clean vehicles that might compete for
the California zero emission vehicle market. Initial results are shown
comparing the marker penetration, societal benefit/cost ratios and re
turn on investment estimates for direct hydrogen fuel cell vehicles co
mpared to fuel cell vehicles with onboard fuel processors including me
thanol steam reformers and gasoline partial oxidation systems. (C) 199
8 International Association for Hydrogen Energy.