technology used in vehicles that use an electric motor for all or part of the motive power of the vehicles, including battery electric, hybrid electric, plug-in hybrid electric, fuel cell, and plug-in fuel cell vehicles, or rail transportation; or equipment relating to transportation or mobile sources of air pollution that use an electric motor to replace an internal combustion engine (ICE) for all or part of the work of the equipment. The sustainable transport movement, part of the environmental movement, has gradually gained in force over the last decade and a half, and has in the process started to shift the emphasis in public spending and actions away from building and supply, to management and demand. The values of respect for the environment and prudent use of natural resources are central, with varying degrees of urgency expressed by different actors and interests. That said, it is still very much a minority movement and most actual expenditures in the sector are determined by criteria other than sustainability. Sustainable Transport is a concept developed in reaction to things that have gone visibly wrong with transportation policy, practice and performance through much the world over the last half of the twentieth century.