Tips for safe cycling #8: filtering (and safe use of the ASL)
It’s one of the joys of cycling that bicycles don’t have to wait in a queue; if traffic is stationary or slow-moving, you as a cyclist are perfectly entitled to move past. Getting to the front of the queue can be advantageous: you get a head-start when the lights change, meaning you can clear the junction more safely, and your visibility is increased, as you can see the whole junction and all other road users can see you. Often, there is a box at the front of the queue to facilitate this: the Advanced Stop Line (ASL) or bike box.
The key here is safety. The bike box is not a target to be reached at all costs. There are many circumstances in which it might not be the safest place: there is a motor vehicle in it (this is an offence which can cost £100 and three points – not many drivers know this!); there is not space to filter safely through the traffic; you don’t have time to get there before the light changes to green; there is a large vehicle or a left-turning vehicle near the box; the box is already full of cyclists. In these situations it might be safer to join the queue in a central position.
If you do decide to pass the queue, two things are needed in order to filter safely: time and space. You may filter on either side of a queue of traffic, as long as there is space: if the left, be aware of left-turning vehicles and vehicles turning into or out of side roads; if the right, be aware of oncoming traffic. Always keep the brakes covered in case pedestrians cross through the queue. You may change position from right to left, but check before you change to ensure no one else is filtering. Keep an eye on the traffic lights – if the lights change to green as you are filtering, join the queue and take a central position in amongst the traffic as it moves off.
There is often a cycle lane leading into the bike box on the left hand side. This doesn’t necessarily mean that’s where you should be, and in fact, if there is a vehicle turning left from the queue, the bike lane is the last place you want to be, especially if it’s a large vehicle. This is where cycling fatalities occur – becoming trapped on the inside of a left-turning vehicle. Be aware that some vehicles might turn without signalling. Often it is safer to filter on the right hand side, or simply wait in the queue (in the centre of the lane).
The full series of tips for safe cycling can be found here.