Lane change on a motorway with a merging truck
You are in the left lane of a three-lane motorway travelling at 100 km/h in a 100 km/h zone. Your exit is 800 metres ahead and requires you to be in the left lane, where you already are. A truck is merging from an on-ramp on your left, and a car in the centre lane is sitting in your blind spot. A solid white line separates the left lane from the hard shoulder, and a broken white line separates the lanes. Ahead, the left lane narrows as the exit slip lane begins. Your mirror shows the car in the centre lane is slightly behind your rear door.
1. Do you need to change lanes, and what are your options?
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You are already in the left lane and your exit is ahead, so you do not need to change lanes. The truck merging from the on-ramp must give way to traffic already on the motorway, but you should assist if safe by adjusting speed. The car in the centre lane is in your blind spot, so a lane change to the centre would be unsafe without a shoulder check and would also take you away from your exit. The correct plan is to maintain your lane, manage the merging truck by easing off or holding speed as needed, and prepare to move into the exit slip lane when it opens. Do not cross the solid white line onto the hard shoulder.
2. How should you manage the merging truck, and what line markings govern the merge?
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The truck is joining from the left and must give way to traffic already on the motorway, but a heavy vehicle cannot stop or accelerate quickly, so be prepared to adjust. If the truck is alongside, ease off slightly to let it in, or hold your speed if it is clearly behind. Do not brake sharply with traffic behind you. The line markings matter: the broken white line between lanes may be crossed when safe, but the solid white line at the left edge must not be crossed except in an emergency. The merge area may have a broken line allowing the truck to enter; you should not move onto the hard shoulder to make room. Signal and make any speed change smoothly and predictably.
3. What checks must you make before entering the exit slip lane, and why?
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Before moving into the slip lane, check mirrors, shoulder check the left blind spot, and confirm the slip lane is clear of vehicles already in it. Signal early. The car in the centre lane is not relevant to a move left, but a vehicle may already be in the slip lane, and the truck may also be heading for the same exit. Reduce speed after entering the slip lane, not before, to avoid disrupting traffic behind. Watch for the exit speed sign and adjust. The key checks are blind spot, signal, and confirmation that the lane you are entering is clear; the solid white line on the far left must not be crossed.