Future railway communications [Guest Editorial]

The growth of intelligent transportation systems (ITS) has recently accelerated as governments and regulators seek to use ITS to achieve important economic and policy goals. ITS must be efficient, environmentally friendly ("green"), and, of course, safe. The scope of ITS is broad, and all transportation modes will require communications, including future vehicular (automotive) systems and vehicle-to-vehicle/vehicle-to-infrastructure (V2V/V2I) communications, aeronautical communications, maritime communications, satellite communications, railway communications, and possibly others.