On 17/03/2017 14:07, dennis@home wrote:

They will save on space required between them when for the portion of
those independent journeys that they are all going in the same
direction for a distance and each individual car is closer than would
be safe with manualy driven ones , no thinking time from human drivers
though it could well seem strange to present drivers who on the whole
get uncomfortable when people Tailgate.

All fine until an artic crosses the central reservation and you discover
you need the same stopping space as you did with a driver.

I'm not sure that's logical. The overall traffic density will be the
same, but it will be much more 'clumpy'. So, if we assume the artic will
wipe out whatever's in its path, with the present system it will
normally wipe out a couple of cars. With the new system, it will wipe
out lots more cars if it hits a train. But there will be big gaps
between trains, so there'll be a big chance of hitting nothing at all.
Overall, it should even up. More or less.

Plus, if the lorry is computer controlled, it won't cross the
reservation just because the driver falls asleep. Or rear-end a bunch of
cars.