Picture of Traffic Jam

Filtering in Traffic: Tips for cyclists to progress quickly and safely

When it comes to road cycling and in particular inner city cycling, the major advantage that the bike commuter has over the motorist is the ability to filter when the traffic is slow moving or stationary. Some motorcyclists have this ability also, but even they will have limitations in comparison to the cyclist on road. This is one of the major reasons why bike commuting can be a faster, more efficient means of transport when it comes to travelling across built up areas.


Filtering basically means making progression by overtaking stationary or slow moving vehicles. It’s absolutely legal to do, but there are many things to taking into consideration in order to do this safely.




The definition of “overtaking” in the UK in this instance is to pass traffic on the right hand side. This is the safest way to filter. Motorists expect other road users to overtake on the right as this is what the highway code dictates, so it is expected especially given that motor vehicle drivers occupy the right seat in their vehicle and will look in their right wing mirror before attempting a manoeuvre. So as a cyclist you are more visible to traffic moving in the same direction and also oncoming traffic when you overtake in this way. If you do veer into the lane of the oncoming traffic you must remember that they have the right of way. It’s a daily occurrence that I see cyclists and also motorcyclists overtaking in the lane of oncoming traffic when there is traffic headed straight for them.





In contrast undertaking is another method of filtering, this simply means passing on the left. This must be approached with extreme caution. Only attempt this if you have the room to do so and traffic is “stationary”. There are a lot of risks when you try and undertake slow moving traffic especially if within that traffic are HGVs (Heavy Goods Vehicle) or buses. These larger vehicles will firstly not expect you to undertake as normal convention is to pass on the right and not left. Secondly if you attempt this you run the risk of being in the blind spot of these larger vehicles which could suddenly move left or turn left without the realisation that you are there. This has proven numerous times to have serious outcome, namely serious injury or death. So if in doubt, wait it out (see Safer Lorry Scheme)


Picture of Traffic Jam


The safety aspect comes in to play when deciding when filter. If you only want to pass a couple of vehicles, then it’s not worth it. If you can make progression and it’s safe to do so in slow or stationary traffic, then by all means advance. A common target for cyclists is the “Advance Stop Line” (ASL), which is the cycling box at the traffic light stop. The ASL makes it safer for cyclists to get room ahead of motorists so that we’re not cut up by them, but sometimes the risk of getting to the ASL is greater. Those are the moments that cyclists should hold back, rather than do something silly.


The main thing to consider when filtering is, “Is it safe to do so”? Then use your judgement and keep your wits about you with each manoeuvre that you execute. Always be aware of what’s going on around you and don’t forget to look back as well as ahead. Other cyclists and motorcyclists may have a similar idea to you with regards to advancing forwards. If there is no ASL ahead then take the lane (primary position) safely behind a vehicle then only move into secondary position (first third of the lane) when it’s safe to do so. Getting back into the stream of the traffic flow needs to approached with just as much caution as filtering, so do it sensibly and if in doubt, WAIT IT OUT.


P.S In countries where you drive/cycle on the right side of the road, the under and overtaking are reversed so make sure that you approach them with caution and awareness before filtering in traffic.


So what do you think about filtering in traffic? Is it an unnecessary risk? Let us know in the comments below.


“Gone riding, be back whenever”



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