Although it’s usually done at a relatively slow speed, filtering is still a fairly dangerous motorcycling manoeuvre.
The most likely cause of an accident while filtering is impatience. Drivers stuck in traffic quickly become irritated with their lack of progress and do stupid, impulsive things.
A few minutes previously they were bombing along at over a mile a minute so to be reduced to a snails pace is understandably frustrating.
The longer the traffic queue, the more likely people are to do something irrational.
On a single carriageway there are several situations you don’t want to find yourself in. The first, and perhaps most likely, is unexpectedly facing a vehicle that’s turned from a side road and into your path.
The easiest way to avoid this is to make yourself as visible as possible by riding well over into the oncoming lane.
By riding closer to the curb than the centre line opens up your angle of view and gives emerging drivers more time to spot you.
If you come across a blind bend or junction, move back towards the centre line and slow right down until you can see clearly again.
Filtering in this way has the added benefit of helping in the second situation you don’t want to find yourself in – when a driver makes an overtaking dash down the outside to a junction or suddenly decides to do a u-turn.
Keeping away from the centre line gives you an improved field of view enabling you to spot likely trouble before it happens.
In slow moving or stationary traffic, vehicles usually sit fairly close together. Drivers thinking about performing a u-turn or a quick dash to a junction will let the vehicle in front pull forward a few feet before swinging out into the oncoming lane.
It’s more difficult to spot these opening spaces if you’re hugging the centre line.
Also, if you do get caught out and a car begins to turn in front of you, by being to the right of the oncoming lane you’ll spot trouble earlier, and be able to brake in a relatively straight line instead of having to brake and swerve as you would if you were closer to the traffic queue.