Transportation and energy are closely linked, and transportation sector is increasing in terms of demand and diffusion over the world. Increasing this sector means to consume more energy to build infrastructures, produce vehicles, and finally power vehicles. Consequently, pollution increases. The goal of clean transportation is to reduce energy consumption developing new technologies in order to offer a better, safer, less pollutant, more available and more reliable service. New options are rising, it becomes necessary to evaluate if these new ways of transportation are practical and at a technological ready-to-go point of advancement, so that financial markets can properly invest and politics can direct the evolution of societies.