I have typically heard of such arrangements for ultra-endurance athletes who cycle through the night - and only at those night-time hours.
As others have mentioned and you seem inclined to use this support vehicle to:
- carry gear
- serve as backup in case riders are particularly uncomfortable with a section of road
I'm sure you'll also need to work out dynamics of how often your support driver stops (only at end of the day or also throughout?) It may also take some extra patience in personality of your support driver to spend a month or two mostly in a situation where they otherwise might wait for people traveling at a slow rate of speed. I know someone who had his wife drive support for a trip across the USA. However, their arrangement was that most of the time, she would wait until he left for the day and then go off to explore nearby towns and only sync up near end of the day.