I'm not sure about that. Keeping the cars closer together would suggest more abrupt acceleration and braking to such to avoid space being created as the car ahead accelerates from a stop. Given these accelerations will not be initiated by the driver, they will come as a surprise and thus be more jarring. I imagine that might result in autodrives that accelerate/brake more slowly, leaving greater distances between cars in stop=and-go environs. And I cannot see autodrives leaving much less room between cars while in steady motion or stopped. Humans are pretty good at tailgating.
At least in theory with proper communication channels between vehicles, vehicles could alter their speed just enough to make space for merging traffic or to allow a vehicle to turn. In that way nobody ever actually stops or starts, they just become slightly slower or slightly quicker, which should be much less jarring.
I think the key is that computer controlled vehicles could synchronize their stopping and starting. You wouldn't have to wait for the few feet moved by the car in front to bubble down the line as drivers notice the extra space. Instead, all stopped cars could coordinate to advance simultaneously.
You wouldn't even have to explicitly sync them; it'll take just few milliseconds for a self-driving car to notice another car is beginning to accelerate. Machines can keep precise control to the level simply unavailable to and unperceivable by humans.
