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The Roundabout


Before we discuss ‘The Roundabout’ lets first consider exactly what it is. A long time ago we used to have just simple cross roads and junctions to contend with, but just as the level and volume of traffic increased so has the complexiCross roads showing priority flow ty and size of junctions, and to move traffic through these areas it has become necessary to organise and control traffic in a very different way. Lets see how this works on a simple cross roads. The major road traffic flow represented by the blue arrows has an uninterrupted access through the cross roads. whereas the red cars have to give way or even stop.Cross roads with small rb

With the introduction of a roundabout the priority which was previously with the red cars has now been removed and the priority is now give way to the right, unless directed otherwise by signs, road markings or traffic lights. This in turn has given all vehicles approaching this junction the same priority with equal access.


Y junctionRoundaboutTsml

The simplest form of roundabout is a ‘T’ or ‘Y’ junction, these may be set in line to form multiple roundabouts or they may be set as a main centre circle with satellite circles on each emerging road. The mini roundabout must be treated just the same as normal roundabouts and you Must pass round the central markings. Avoid makings U-turns on a mini roundabouts.


Approaching the roundabout

Most of the hard work on roundabouts is performed well before the actual junction. This is accomplished by good planning, good observations and hazard awareness.

Planning your approach

On approach to the roundabout mirror signal manoeuvre (MSM) look well ahead taking note of the volume of traffic,speed and position of vehicles on, or approaching the roundabout. Be sure to check our own driving mirrors and blind spots for other vehicles speed, and position, look out for signals if any are given. If the road ahead is clear try to adjust your arrival speed at the roundabout to coincide with a gap suitable for you to drive into, follow through into the available space. Make sure you do not affect or make any other road user alter their speed or direction as a result or your actions.

For most roundabouts approach in 2nd gear with speed of 15 to 20 mph, however this will vary with the size, shape and exit position on the roundabout. If you’re access is not clear or you have to slow down due to congestion, be prepared to stop on the give way line and wait for a clear and safe space. Once you have seen a suitable space prepare the car to move into the space and follow through, in other words follow on behind the last vehicle. Make sure you do not make any other road user alter their speed or direction as a result or your actions.

Turning left (first exit)

Plan your approach take the left lane on approach to the roundabout ensure the left signal is applied in good time RoundaboutLeftTurn(MSM). When it is safe enter the roundabout keeping close to the left, look ahead to your exit. If your exit road has 2 lanes keep in the left lane. Use your mirrors and check your blind spot (right) to see if any other vehicle is trying to leave the roundabout at the same time. Look for any deviation or road narrowing markings. Check centre mirror on exiting the roundabout and take note of any vehicles that have followed you off the junction.



Going ahead (second exit)

Plan your approach look well ahead and follow the road markings for ahead,RoundaboutAheadthis is usually the left lane on a single carriageway and the centre lane on a dual carriageway (be aware these rules may differ from one roundabout to the next). Remember you MUST give way to the right and that you MUST NOT alter or change the speed of any road user already on the roundabout by your actions, so allow a suitable space for your skill and judgment on entering the roundabout.


The danger zone and shield

Before you commit to the junction pay careful attention to any moving traffic approaching from the road immediately to your right as these vehicles may be approaching at some speed and could be in front of you before you can say ‘knife’. Look for a window of opportunity when traffic is exiting the roundabout immediately to your right i.e. travelling on the same road as you but in the opposite direction, traffic approaching on the road to your right must give way to the through traffic, this gives a small but available window from which you can emerge onto the roundabout. You can also make use of any large slow vehicles such as lorries and coaches which are turning right or taking an exit further round the roundabout from yours and use them as a shield. When they start to emerge you can move off at the same time keeping pace with them, do not fall behind them as you will be exposed to vehicles already on the roundabout. Chooses your shields with care as super bikes and Ferrari’s do not make good shields.

Look for lane markings on the roundabout these may be faint or worn away if there are two lanes stay in the left hand lane, if there are three lanes choose the centre lane , keep your mirror and observations up to date and as you approach the exit before yours give a left signal MSM and prepare to exit in the left lane if available otherwise exit in the right hand lane and then negotiate to move over to the left as soon as it is safe to do so, you may have to increase your exit speed in order to move over to the left lane.. Once in the new road recheck your mirrors and make sure your signal has cancelled.

Turning right or ‘U’ turn

Look well ahead on a single lane approach road keep just left of the centre, if more than one lane is marked on the approach look at the road markings and choose the appropriate lane (usually the right hand lane). Use the same method on planning your approach as above, once on the roundabout use the inside (right) lane, before you approach the exit, check the road immediately on your left then centre and left dDangerZoneoor mirror, check left blind spot and apply a left signal to leave the roundabout. If there is no activity in front and to the left and no activity behind and to the left exit in the left hand lane, but if you have vehicles emerging from the road on your left or following you in your left blind spot exit in the right hand lane and then negotiate to move over to the left as soon as it is safe to do so, you may have to increase your exit speed in order to move over to the left lane.


Roundabouts that change the rules



The Gyratory

This style of roundabout Gyratory roundaboutis marked out with dedicated lanes, on approach look at the information sign and select the correct lane for your exit emerge onto the roundabout in the normal way. KEEP in your designated lane and be aware of traffic around you, on some gyratory systems traffic lights may be deployed to assist the flow of traffic as well as yellow box sections be sure to comply with all lights and direction arrows stay in lane, if you find yourself in the wrong lane DO NOT change stay in lane, exit then return to re-negotiate choosing the correct exit. When exiting in the left lane no signal is required, a left signal will be required if you are exiting in the right (off side) lane of the new road.




Roundabouts of notoriety


Longbridge roundabout at the end of the Gatwick by-pass is on its third version of lane markings and has taken some time for local traffic to understand its foibles. Notice there are 4 area's that break away from the conventional roundabout.

(1) The offside lane of the dual carriageway breaks into two lanes.

(2) Two lanes merge into a single lane which becomes the offside lane of the dual carriageway.

(3) One can use either lane for a right turn from this approach.

(4) Two lanes merge into a single lane.

Longbridge roundabout

Cheals Roundabout

Cheals roundabout CrawleyWhen going ahead travelling north on the A23 in the direction of London & Gatwick enter the roundabout in the right hand lane be sure to exit in the right hand lane and come over to the left as soon as it is safe to do so.

Approaching Cheals from the Horsham road turning left is a filter left only and roundabout rules do not apply, treat as a left turn. When going ahead use the right hand lane on approach.


It used to be called the Plough or Moor End roundabout but the "Magic" roundabout, or the funny roundabout, as it tends to be calleMagicRB Hemeld now, was built to cope with the increased congestion that came as Hemel grew. On the first day of operation in June 1973, traffic came to a standstill and backed up to Berkhamsted. Drivers eventually got used to it although you still see the odd trilby hatted motorist causing chaos and looking totally lost on the roundabout.