The message
from raden contains these words:

Dunno about you, but at a steady 70 mph, I'm driving in an unconscious
overdrive

Mind bogglingly boring isn't it?

At 120+ mph, I'm fully alert

I don't get to drive at that speed very often but at 70 (or more) mph on
a modern single carriageway or 20 mph (or even less) on a blinkered
single track road so am I. :-)

As I have said on this ng before I am determined to give up driving when
I reach the point where I find 70 mph in any circumstances too fast for
comfort. Meanwhile I think any driver, whatever their age, who is
already in that condition should stop driving immediately. They just
haven't got what it takes to cope with an emergency.

--
Roger Chapman