Traffic lights... why do we have two of them.
Discussion
This is my theory. For a solid stop line on the road to be enforceable it needs to be supported by a sign next to it, this could be a stop sign (as opposed to a give way) or a traffic light. The traffic light needs to be next to the line at the junction but it is hard to see if you are first in the queue so one is placed further back to make it easier to see. If we just used the one further away the line would have to be moved forward to make it enforceable thus being back to square one.
Now the interesting bit in my view is these advanced stop lines, common sense would say if there are two stop lines then there needs to be two traffic lights, so in my opinion junctions with only one light there should have one stop line, how do they get away with enforcing two lines with one traffic light.
Now the interesting bit in my view is these advanced stop lines, common sense would say if there are two stop lines then there needs to be two traffic lights, so in my opinion junctions with only one light there should have one stop line, how do they get away with enforcing two lines with one traffic light.
In this example they are termed closely associated secondary signals. They are designed to be visible to the driver at the stop line, whereas the primary signal nearest the stop line is likely to be alongside the first driver, making it awkward to see.
Often the secondary signal is on the far side if the junction, but this can cause issues with other movements of traffic seeing this signal change and use that as their stimulus to start moving during the safety clearance period of time. It is mandated in the UK that we must have at least one primary and one secondary signal at each approach to a junction.
Other countries do not buy into is guidance so there are examples where just a single signal is used. Difficult to prove that two is necessary for safety reasons as it's hard to isolate just that design feature between the two countries, for instance other traffic legislation is different so collision stats are not always telling an accurate story when compared.
Often the secondary signal is on the far side if the junction, but this can cause issues with other movements of traffic seeing this signal change and use that as their stimulus to start moving during the safety clearance period of time. It is mandated in the UK that we must have at least one primary and one secondary signal at each approach to a junction.
Other countries do not buy into is guidance so there are examples where just a single signal is used. Difficult to prove that two is necessary for safety reasons as it's hard to isolate just that design feature between the two countries, for instance other traffic legislation is different so collision stats are not always telling an accurate story when compared.
V8forweekends said:
I like the French ones where they have a small repeater set lower down on the pole for the vehicle at the head of the Queue - would save a fortune, except they'd probably get vandalised to flip here.
We will find out, the small signals have been installed low down for cyclists at Bow roundabout in London.
silent knight said:
V8forweekends said:
I like the French ones where they have a small repeater set lower down on the pole for the vehicle at the head of the Queue - would save a fortune, except they'd probably get vandalised to flip here.
We will find out, the small signals have been installed low down for cyclists at Bow roundabout in London.(please notice smiley up top)
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