Grid-connected vehicles (GCVs)-e.g., electric trains, metros, trains, and trolley buses-are propelled by electric motors directly connected to remote power sources. Their low at-vehicle energy consumption and ability to use a wide range of renewable energy sources make them strong contenders for urban and interurban transport systems in an era of energy constraints that favours use of renewable fuels, which may lie ahead. Needs for autonomous motorised mobility could be acceptably met in large measure by deployment of personal GCVs, also known as personal rapid transit (PRT). Alternatives, including fuel-cell vehicles and dual-drive vehicles fuelled with ethanol, will be less feasible. The 'car of the future' may not be an automobile so much as a PRT element of a comprehensive GCV-based system that offers at least as Much utility and convenience as today's transport systems. (c) 2006 Elsevier Ltd. All rights reserved.