Hydrogen vehicles (H2V), including H2 internal combustion engine, fuel cell and fuel cell plug-in hybrid, could greatly reduce petroleum consumption and greenhouse gas (GHG) emissions in the transportation sector. The U.S. Department of Energy has adopted targets for vehicle component technologies to address key technical barriers to widespread commercialization of H2Vs. This study estimates the market acceptance of H2Vs and the resulting societal benefits and subsidy in 41 scenarios that reflect a wide range of progress in meeting these technical targets. Important results include: (1) H2Vs could reach 20–70% market shares by 2050, depending on progress in achieving the technical targets. With a basic hydrogen infrastructure (∼5% hydrogen availability), the H2V market share is estimated to be 2–8%. Fuel cell and hydrogen costs are the most important factors affecting the long-term market shares of H2Vs. (2) Meeting all technical targets on time could result in about an 80% cut in petroleum use and a 62% (or 72% with aggressive electricity de-carbonization) reduction in GHG in 2050. (3) The required hydrogen infrastructure subsidy is estimated to range from $22 to $47 billion and the vehicle subsidy from $4 to $17 billion. (4) Long-term H2V market shares, societal benefits and hydrogen subsidies appear to be highly robust against delay in one target, if all other targets are met on time. R&D diversification could provide insurance for greater societal benefits. (5) Both H2Vs and plug-in electric vehicles could exceed 50% market shares by 2050, if all targets are met on time. The overlapping technology, the fuel cell plug-in hybrid electric vehicle, appears attractive both in the short and long runs, but for different reasons.