Roundabouts are a very good method of easing traffic flow at busy junctions. The general rule governing the behavior of traffic at roundabouts is that drivers should 'give way' to any traffic to their immediate 'right' unless otherwise directed by road signs, markings or traffic lights. This is implemented by the presences of a white Give Way line across the entry arm of a roundabout. You should use the MSPSLADA routine on approach and throughout the roundabout.
12 o'clock rule
The 12 o’clock rule is a basic rule that gives us a starting point when thinking about how to deal with different roundabouts.
Generally speaking small to medium sized roundabouts will at best only have enough room to fit two vehicles on them side by side as they travel around it. This means we can either position well to the left or well to the right when negotiating a roundabout.
It is important to position correctly on approach to and throughout a roundabout, this is in order to help ease traffic flow and to avoid any potential conflict with other traffic on the roundabout intending to pass on the left or right.
So the question is: “How do we know which position to take up for various exit routes when approaching a roundabout?”
To answer this question we are going to think of the roundabout as a clock face and whenever we come to a roundabout we will be approaching it from the 6 o’clock position and straight ahead will be 12 o’clock.
Taking a look at the diagram above you will notice the green shaded area starts at 6 o’clock (entry point onto the roundabout) and finishes at 12 o’clock (exit point for straight on third exit).
OK so for the 12 o’clock rule:
unless road markings or signs indicate otherwise you should position to the left or in the left-hand lane when taking any exit up to and including the 12 o’clock exit. Any exit after 12 o’clock you should position to the right or in the right-hand lane.
Take a look at the next diagram below to see how this works.
Next I would like to talk about how to assess whether it is safe to emerge onto a roundabout. For this I would like you to take another look at the first diagram and take note of the red shaded area (remember we are approaching from the 6 o’clock position where the white arrows are). This area between the 3 o’clock and the 6 o’clock position is where we must give way to traffic that is continuing round past the 6 o’clock position.
So when approaching a roundabout we should make a positive decision to hold back and give way to any traffic that is within the red shaded area. The reason for this is that we most not cause any traffic to unnecessarily alter their position or speed due to our decision to emerge onto the roundabout. Also we need to think about the amount of safety space that any approaching traffic will have to allow them the chance to stop in time should the vehicle we are driving stop suddenly such as if the engine stalled due to a mechanical or electrical breakdown.
To be continued.
Medium size roundabout
View Larger Roundabout
Related Links: Mini-roundabouts Spiral roundabouts Driving Skills
Driving Instructor Dewsbury