I haven't bothered reading since I last posted but it is probably worthwhile picking up on this point.
All drivers drive at a speed they believe they can stop in the distance they can reasonably expect to remain clear unless they admit to driving recklessly. As a rule it tells us nothing about advanced driving.
What it can do, is remind those of us who are familiar with Roadcraft/HTBABD, the process of identifying an approprite speed. Briefly; looking ahead, behind, laterally, identifying what you can see; what you cannot see; considering what might happen; prioritising hazards.
This process is underpinned by the rule that one must be able to stop in the distance seen to be clear.
The process cannot be condensed into half a sentence. There is no point in trying to achieve the impossible.
The problem, identified by hir and others is that we can focus too much on the underlying rule and not give enough attention to the rather more complex process, (arguably the essence of advanced driving) of identifying an appropriate speed.
The so-called unofficial 'rule' is simply a reminder to put the 'official' rule in the context of the process described above.
When a contributor asks a question that implies he has little or no knowledge of advanced driving such as,
kitkatbrown wrote:Hello, i wondered if someone who has undertaken the advanced driving course could advise on what the advanced driving course teaches as regards dealing with cars overtaking in dangerous places.
how is it helpful to use a phrase that simply gives a nod to what is written in Roadcraft/HTBABD, rather than explaining its content?
If one seeks an unofficial rule that does a bit of both no one would use the expression
'you can reasonably expect to remain clear' unless they were trying to do something more than make a helpful statement.