7.2 Roundabouts, Merging and Road Markings
Key Takeaways
Give way to vehicles already in the roundabout; the rule is not simply give way to anything on the right.
When a marked lane ends, give way to traffic in the continuing lane; in an unmarked merge, the vehicle behind gives way to the vehicle ahead.
Keep left on applicable multi-lane roads over 80 km/h or where signed, subject to the road-rule exceptions.
Read a roundabout as an intersection
Approach a roundabout at a speed allowing you to stop and select a suitable gear before entry. Look at the signs, lane arrows and circulating traffic. Give way to vehicles already in the roundabout. A vehicle approaching from the right but not yet in it does not automatically have priority merely because it is on your right. Still observe all approaches and avoid entering into a developing conflict.
A long vehicle requires room for the trailer’s cut-in and the rear body’s swing. Do not assume a clear cab path proves a clear trailer path. A turning sign and the applicable long-vehicle exceptions can affect positioning, but there is no blanket permission to drive over a kerb or occupy every lane. Choose a route and path appropriate to the actual vehicle.
Approach lanes and signals
For a left turn, generally approach in the left lane and signal left. For a right turn or travelling around to return, generally approach in the right lane and signal right. For going straight ahead, use a permitted lane and do not signal an intended turn on approach unless the movement requires it. Follow lane arrows where they specify a different permitted movement.
Signal left when leaving the roundabout if practicable, including when going straight ahead. Maintain the selected path and check for traffic beside the vehicle. A lane change within the roundabout requires signalling and giving way to vehicles in the destination lane. The fact that the truck entered first does not reserve an adjacent lane.
| Decision | Rule or observation |
|---|---|
| Entering | Give way to vehicles already circulating |
| Choosing lane | Follow arrows and the permitted path for the intended exit |
| Changing lane | Signal and give way to traffic in the destination lane |
| Leaving | Signal left if practicable and check the exit path |
| Long vehicle clearance | Monitor cut-in and tail swing; use only applicable exceptions |
Cyclists can use roundabouts and may take a position that improves their safety and visibility. Do not squeeze past within a narrow circulating lane. Allow enough time and space for them to travel through and watch for riders at exits and crossings. A heavy vehicle’s mirror view can change rapidly through the curve.
Marked lane ending versus an unmarked merge
When a marked lane ends and the driver must cross a lane line into the continuing lane, the driver changing lanes gives way. Do not assume the vehicle furthest ahead always has priority in that layout. A merge arrow warns of the lane change; it does not transfer priority.
When two lines of traffic merge without a marked lane boundary between them, the vehicle behind gives way to the vehicle ahead. This is the context in which the ahead/behind merging rule applies. Identify the road markings before choosing a slogan such as 'zipper merge'. Even with priority, adjust speed smoothly and avoid trapping another vehicle beside a long trailer.
Keep left and use lanes correctly
On a multi-lane road with a speed limit over 80 km/h, or where a KEEP LEFT UNLESS OVERTAKING sign applies, do not remain in the right lane except as the rules permit. Exceptions include the relevant turning, overtaking, obstruction and congestion situations. Lane-specific signs can impose additional restrictions, so check whether a truck lane or restricted lane applies.
On roads without multiple marked lanes, keep as near as practicable to the left while maintaining a safe margin. Do not use a soft shoulder as if it were a normal lane. Avoid driving along an emergency stopping lane or bicycle lane except under the actual permitted exceptions. A delivery deadline does not make a special-purpose lane available.
Dividing and lane lines
A broken dividing line can permit crossing for a lawful safe movement, such as overtaking, when visibility and other rules allow. A continuous dividing line generally restricts crossing. A continuous lane line can restrict changing lanes. Double-line arrangements require attention to the line nearest the vehicle and the actual rule.
There are specific exceptions for activities such as entering or leaving the road, avoiding an obstruction and safely passing a bicycle under the stated conditions. An exception is not permission to cross into unseen oncoming traffic. Confirm that it applies and that the movement is safe. If the safe clearance cannot be provided, wait.
Painted islands, medians and turn lanes also have defined uses. Do not treat a painted area as free space for a long vehicle whenever a corner feels tight. Select the lawful approach early; if you miss the turn, continue to a safe alternative rather than cut across several lanes at the last moment.
A merging example
An HR truck is ahead of a car in a lane that ends at a broken lane line. The truck still must give way when entering the car’s continuing lane. In a different layout with two unmarked streams narrowing to one, an ahead vehicle can have the relevant merge priority. The geometry changes the answer, not the truck’s size.
Key decisions
Identify circulating traffic, approach markings and merge geometry. Plan the entire vehicle path and preserve clearance instead of relying on informal priority assumptions.
Official sources
Road Rules 2019, roundabouts, lane use, merging and line rules; official Road Rules Handbook. Sources checked 10 October 2026.
A truck’s marked lane ends and it must cross the lane line into a continuing lane occupied by a car. Who gives way?
The car always gives way because the truck is longer
The truck changing lanes gives way to the car in the continuing lane
The vehicle behind always gives way regardless of markings
Neither has a give-way duty if both signal
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