Peter,
I work in Road Safety and have done so for near on 40 years. It is true, driver reaction times vary from 1.5 sec to 3 secs. It is from the time the eye sees, to the brain analysing and the foot reacting. F1 drivers can get this down to less that 0.5 sec, but they are the exception. Drag car drivers can get it down to 0.1, but that is with anticipation of a start.
Road safety has been promoting the 2 sec drop back rule for a long time. Simply, as the car in front you passes an object there should be a 2 sec gap till you pass the same object - regardless of speed.
We all need to drive safely on our roads.
Clear skies
Rod
