Fault After A Lane-Change Crash
A vehicle swerved into your lane and now you are left dealing with the damage.
A driver who moves into another lane without confirming it is clear usually carries the fault. The argument usually comes down to whether you were already alongside, or arrived quickly from further back.
It happens in seconds on a highway like the North-South Expressway or LDP. A car drifts across without signalling, and two people are each sure the other was speeding.
What a court weighs
The driver making the move is expected to signal and check the lane is clear. If they did not, that weighs heavily against them. The court also asks whether your vehicle was already visible and entitled to be there, or appeared suddenly at a speed that gave the other driver no chance to react.
Neither question decides the case alone.
The evidence that settles a lane-change dispute
Whether the indicator was used, shown by dashcam footage or a witness, tends to carry the most weight. The pattern of damage matters too, since a side-swipe shows the angle of contact and which vehicle was struck. Relative speed, worked out from dashcam or skid marks, fills in the rest.
Record the final position of both vehicles against the lane markings before anyone moves. Make your police report as soon as you can.
Does being partly at fault end my claim?
No. A motorcyclist without a helmet, or a car occupant without a seatbelt, can have their compensation reduced for that. This is separate from who caused the lane change.[1] Contributory negligence explained sets out how the reduction is decided.
When there are no witnesses
A lane-change crash often has few independent witnesses, since it happens fast. Without dashcam footage, the dispute can come down to two accounts that disagree.
What to do next
Ask nearby drivers to stay and give a short statement. They may have seen more of the approach than you did. Who is at fault in a crash covers the broader principles.
When the other driver disputes what happened, an independent lawyer can take on the claim and deal with the insurer. For the first contact, share general dates, location, case status and a short summary only. Keep documents private. Only after an identified lawyer or law firm contacts you and specifically asks for them should you provide that identified lawyer or firm with the accident date, where it happened, whether anyone was injured (yes/no), any dashcam footage and the police report status.
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Common questions
Is the driver who changed lanes always at fault?
Usually yes, since a lane change is only supposed to happen once the driver has confirmed it is clear. Blame can still be shared if the other vehicle was speeding, or appeared where it genuinely could not have been seen in time.
What if the other driver claims I was in a blind spot?
A blind spot does not remove the duty to check mirrors and glance over a shoulder before moving. It can still turn into a real factual dispute, and dashcam footage or an independent witness often ends up deciding it.
I was side-swiped while riding a motorcycle. Do the rules differ?
The same fault principles apply, though courts are aware that riders are harder to spot in a mirror check. [Motorcyclist support after a crash](/motorcyclist-injury-help/) covers what tends to strengthen a rider's evidence in this situation.
Does not signalling automatically prove the other driver was at fault?
It is strong evidence against them, but a court still looks at the whole picture, including your own speed and position, before deciding how responsibility is shared.
Sources
- Civil Law Act 1956, s.12 (Attorney General's Chambers) (accessed 2026-09-22)
Need a lawyer to handle your injury claim?
For people seeking legal representation. For general information, please use our guides and tools.