(01-06-2011, 10:47 PM)Peter Wrote:(01-06-2011, 09:00 PM)fil Wrote: Hi again ppl,
i keep reading about defensive driving.
i dont know the exact meaning of it or where it came from, can anyone help?
is it a recognised part of driver training or an undesirable trait?
any help would be great guys.
It is part of most UK train operator's driving policy and at its simplest says that drivers should aim to drive so that they stop gently well before the signal. Layout of stopping positions on stations and phones at other signals will generally assume a stopping position 20m from the signal to allow for defensive driving.
You may also see it referred to as "Professional Driving". Different Train Operatoring Companies have slightly different policies, but generally they include:
a) braking significantly on seeing a cautionary signal (i.e. generally on seeing it, not waiting until arrived at it; bpplying brakes even if happpen to be travelling rather slower than maximum permissible speed, so as not to "ignore" and risk forgetting despite there actually being no immediate need to slow.
b) targetting a specific (pretty low) speed at the AWS magnet used as a marker 180m prior to signal and then all but coasting to a stand,
c) stopping well prior to a signal so that there is both a margin for error and indeed by standing some 15 - 25m back from a signal making it far easier to observe when waiting for it to clear.
There are other elements but the ones above are the most relevant for the Signalling Engineer, since have implications regarding
1. the headway that can be achieved (worsened),:
2. the risk associated with a SPAD (lessened),
3. the standage on the layout that can be achieved (reduced),
4. the placement of AWS (increased importance from TOC perspective of always placing athem t 180m - or more for the highest speed lines- which is at variance with the formeer practice of placing deliberately closer where the permissible speed pretty low)
5. signal sighting considerations
From IRSE Exam purposes, most of these are actually more relevant to Mod 2 than Mod 3 as they have most to do with "Signalling The Layout"
PJW