There are currently no commercially available hydrogen vehicles. However, various tests are being run by the U.S. Department of Energy's Advanced Vehicle Testing Activity to gauge the feasibility of using hydrogen in internal combustion engines. A recent activity tested the safety and operation of a Mercedes Sprinter Van running on pure hydrogen as part of the Arizona Public Service fleet. For information on this vehicle and other hydrogen vehicle testing, see the DOE Advanced Vehicle Testing Activity site.
In addition, vehicles can run on hydrogen/compressed natural gas (HCNG) blends. Currently, tests are being run by DOE on transit buses that can fuel with HCNG blended at a ratio of 20% hydrogen to 80% compressed natural gas.