I'm happy to accept your correction in my first para (albeit IME the time between "1" disappearing from the countdown and engines revving is so small as to suggest the all-red period is practically non-existent), but I am more than puzzled as to why on earth you feel the need to characterise me as "those such as yourself who don't wish to do maths" and "maths hating persons, [l]ike yourself."
Sorry, I was just jokingly referring to your line
'I dislike the TfL implementation (of seconds left until green for motor traffic), as I seem incapable of interpreting it as anything other than '3 seconds - sure, that's plenty of time to get across the road.' '
as meaning you didn't like doing maths to work out if you had time left to start crossing.
I wasn't referring to maths in any other context
So apologies.
I have edited the original post to clarify it.
NB I started this thread because I thought there might be a more intuitive (graphical) and friendly way of giving pedestrians amber info from which they can deduce if time remains for them to start crossing so I sort of include myself in 'people who don't wish to do maths' when crossing...
I thought people would know roughly what speed (fast, medium, slow, very slow) they walked at, so simple graphics based on that might be better but....
NB IMO Engines revving is just impatient bad drivers for whom the highway code instruction that they should not intimidate pedestrians still crossing passes over them: I have seen someone drive straight through the red road signal while pedestrians were still crossing during blackout just because they must have decided their own traffic light had stayed red too long (they had been stopped for less time that they would have been at a pelican (because it was a smart crossing) so a pity no police were passing ....). The pedestrians would have been perfectly visible to them.
NB you can find documents with UK timings on the web(of course I have now forgotten how I found them ):
but red with amber period is 2 seconds
so road traffic is forbidden to cross the stop line for at minimum 2 seconds
but I think at farside crossings there will always be at least another second of all-red.
So your revving drivers are simply bad drivers.