Roundabout Entry with a Blocked Exit and a Tailgating Lorry
You are driving a saloon car north on a two-lane approach to a large four-arm roundabout. Your intended exit is the third arm, a dual carriageway heading west. Traffic is heavy and moving at about 30 km/h. As you reach the give-way line, you see that the exit road you want is backed up: the queue on that exit begins about 40 metres past the roundabout and is stationary. A loaded lorry is following you closely, roughly one car length behind, and its driver has already begun edging to your right. The circulating lane nearest you has a steady stream of vehicles, but a gap of about three seconds is approaching from your right. Your lane position is the left of the two approach lanes.
1. Should you enter the roundabout on this gap, given the blocked exit ahead? Explain your decision and what you should do with your lane position.
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Do not enter on this gap. The gap is adequate for the circulating movement, but it is not adequate for your whole journey through the roundabout. Because your exit is blocked 40 m beyond the roundabout, entering would leave you stopped inside the circulatory carriageway, blocking the flow for vehicles already circulating and for those entering behind you. A driver must not enter a roundabout unless the way beyond the exit is clear enough to clear the junction.
The correct action is to hold at the give-way line, keep the car square in the left approach lane, and wait until the queue on your exit has begun to move so that you can cross the roundabout without stopping on it. Do not drift right to 'claim' a gap: the lorry is close behind and is already edging right, so a late lateral move risks a sideswipe. Signal left only when you are actually about to leave at your exit.
If traffic behind becomes impatient, that does not change the rule. Blocking the circulatory carriageway is both a hazard and, in most jurisdictions, an offence.
2. The lorry behind is one car length back. What risk does this create at the give-way line, and how should you manage it while you wait?
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A one-car-length following distance at 30 km/h gives the lorry driver almost no reaction time. If you stop at the line and then, for any reason, roll back or move off and stop again, the lorry may not be able to stop. The risk is highest if you begin to enter, then abort because the exit is still blocked: the lorry driver may have committed to following you into the roundabout.
Manage it by making your intentions unmistakable and early. Keep the footbrake applied while stationary so your brake lights are visible. Leave a slightly larger gap to the give-way line than usual so you have room to roll forward without entering the junction. Avoid creeping forward and stopping repeatedly, which invites the lorry to close up. If the lorry's behaviour becomes genuinely dangerous, consider whether you can safely let it pass before the roundabout rather than being pushed into a gap you would not otherwise take.
Never let a tailgating vehicle dictate your entry decision. Your obligation is to enter only when it is safe for you and for circulating traffic.
3. Once the exit queue clears, describe the sequence of observations and signals you should complete before and during the entry.
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First, re-check the circulating traffic to your right, because the situation has changed while you waited. Look right, then ahead into the roundabout, then right again: the second look right confirms that no new vehicle has arrived in the gap you intend to use.
Check your mirrors, especially the left door mirror, for cyclists or motorcyclists who may have come up on your left inside the approach lane. Give a left signal only as you approach your exit, not from the give-way line, so the signal is not misread as an intention to turn left into the first arm.
Enter in the left lane, keep left of the circulatory centre, and maintain a steady speed so following traffic can read your path. As you pass the second arm, confirm the exit is still clear, check the left mirror for anyone overtaking on your left, then signal left and leave. After leaving, cancel the signal and check the mirror before adjusting speed to the new road.