According to Gizmag, the European Union is seriously investigating technology to link together vehicles for land convoys. The Safe Road Trains for the Environment (SARTRE) project is exploring whether vehicles fitted with a navigation system can create virtual linkages so that only the driver at the front (who would be an authorised convoy leader) has to drive and the rest can follow behind until they decide they want to pull out.
This could work very well, especially with electric vehicles where lowered wind resistance could help greatly extend the range. I suspect that practical implementation will be a long way off but I look forward to hearing more as this particular bit of “science fiction” thinking integrates into reality.