To Split or to Filter

Learners often ask about the legalities of lane splitting. The usual wording is: “Is it OK to ride between two lanes of cars, down the middle?”

My follow-up question is: “Are the vehicle in the lanes stationary, or are they both moving?”
The answer makes all the difference.

Filtering vs. Splitting

Lane Filtering: When traffic is stationary or travelling very slowly and a motorcycle carefully rides between lanes to reach the front of the queue at lights.
Lane Splitting: When traffic in both lanes is moving, and a motorcycle rides between them, effectively creating a new, unmarked lane.

The Legal Context in WA

The Motorcycle Riders Association of WA clarifies filtering by referring to Road Traffic Code Regulation 122:

Reg 122(1): A vehicle (other than a bicycle) must overtake on the right of a moving vehicle, at a safe distance.
Since filtering occurs when vehicles are stationary, this regulation doesn’t apply.

This means that filtering, done carefully and responsibly, is not unlawful in Western Australia.

Since March 2021, lane filtering has been legal in WA — but only under strict conditions.

✅ When it’s allowed

Rider is travelling 30 km/h or less
Moving between two lanes of stationary or slow-moving vehicles going in the same direction
Only if safe to do so

❌ When it’s illegal

Across pedestrian, children’s, or marked foot crossings
In school zones or shared zones
Where the speed limit is 40 km/h or below
Between heavy vehicles
Around merging traffic
In a ‘no overtaking’ zone
On roundabouts
Beside bicycle lanes, bus lanes, or other special-purpose lanes
Alongside the kerb, road edge, or parked cars
While on a learner’s permit

⚠️ Bottom line: Lane filtering can improve traffic flow and rider safety — but only when done slowly, legally, and responsibly.

My View on Filtering

Filtering helps motorcyclists reduce the risk of being rear-ended by moving up and away from cars stuck in traffic. Riders also tend to accelerate away from lights faster than cars, so filtering eases congestion by removing one more vehicle from the queue. Done safely, filtering is a practical and accepted riding technique.

My Position on Splitting

I want to be absolutely clear: I do not endorse lane splitting between two lanes of moving cars.

It is against the law in WA.
It creates unnecessary risks by riding in an unmarked “imaginary” lane.

While some riders may choose to split lanes, the risks rise dramatically:

At speeds up to 40 km/h, a very experienced rider might be able to brake within a car length, making it “survivable” but still illegal.
At speeds above 40 km/h, lane splitting is highly dangerous. If you want to overtake, pick a lane, wait for a safe gap, and do it legally.

Final Thoughts

Filtering when traffic is stopped can improve safety and traffic flow. Splitting when traffic is moving is both illegal and dangerous. At BikeSAFE Motorcycle Training Perth, we teach strategies that put rider safety first.