氢气车分为两种，氢内燃车(HICEV)是以内燃机燃烧氢气（通常透过分解甲烷或电解水取得）及空气中的氧产生动力，推动的汽车。而氢燃料电池车(Fuel cell vehicle-FCEV)是使氢或含氢物质及空气中的氧通过燃料电池以产生电力，再以电力推动电动机，由电动机推动车辆。这类车辆的发电厂把氢的化学能转换为机械能，或者是通过燃烧的内燃机中的氢，或通过在燃料电池中的氧与氢反应来运行电动机。广泛使用氢助长交通是在提议中的氢经济的一个关键因素。

使用氢为能源的最大好处是它能跟空气中的氧，产生水蒸气排出，有效减少了其他燃油的汽车造成的空气污染问题。

A hydrogen vehicle is a vehicle that uses hydrogen as its onboard fuel for motive power. Hydrogen vehicles include hydrogen fueled space rockets, as well as automobiles and other transportation vehicles. The power plants of such vehicles convert the chemical energy of hydrogen to mechanical energy either by burning hydrogen in an internal combustion engine, or by reacting hydrogen with oxygen in a fuel cell to run electric motors. Widespread use of hydrogen for fueling transportation is a key element of a proposed hydrogen economy.