FilteringWhenever the subject of filtering comes up we often get asked the question “Is it legal?” The simple answer is “Yes.” There is a ‘but’ though. Filtering is legal if it is done with ‘due care and attention’, and is not ‘dangerous’. Filtering isreally just overtaking slow moving vehicles, remember overtaking is illegal where there is a no overtaking sign, where there is a double white line and it would be necessary to cross a solid one closest to you, on hard shoulders on motorways and the approach to pedestrian crossings.


Filtering is one of the real benefits of riding a bike and a reason so many of us commute to and from work. We need to accept that it can be quite risky. Riding a motorbike is all about ‘risk management’. We are constantly balancing competing demands, the need to get somewhere over the need to stay safe. We all have a threshold of acceptable risk, that threshold is not the same for everyone. I see this demonstrated every day by motorcyclists, as I filter on my journey to work, I am quicker than some and slower than others. So, in general, my threshold of acceptable risk is higher than some and lower than others. I believe this threshold rises as we become more familiar with the task. We reach a state of mind that convinces us that because nothing bad has happened yet then the task must be safe. So we should keep asking ourselves, “Are we really riding safely?”


I am often shocked just how fast some bikers choose to filter. When filtering we are relying on others to ‘do the right thing’. We are placing our trust in others not to change lanes without looking or shut the gap as we pass. If I asked you to give me your bank card and the pin number but I promised not to withdraw any money you wouldn’t even consider it but you will place your safety in the hands of another you have never even met and whose driving skill or state of mind you don’t have a clue about.


It is a disturbing fact that riders lose their lives or suffer life changing injuries whilst filtering, which is a fact in my line of work I am only too aware of. I would bet they, like you now, thought it would never happen to them.


Recently I was travelling home from work filtering on the M25 in stationary traffic between lanes 3 & 4 when a van driver decided to get out of his van to see what was causing the delay, he swung open the drivers door directly into my path, I struck the door just left of centre of my fairing. Me, and the bike, then hit the rear of a stationary car in lane 4. I was carted off to Watford General Hospital courtesy of the ambulance service and the bike to a local recovery yard. I sustained whiplash; the bike was a write off. It could have been so much worse and I thank my lucky stars that I have a lower threshold of acceptable risk than some. I attribute my relative lack of injuries to two factors, I was not travelling fast and I was wearing good quality motorcycle clothing, even my gloves had armoured knuckle guards. Sometimes there is just nothing you can do but the risk of serious injury is lessened by lower speeds. That is just basic physics, more speed = more energy = “This is going to hurt more if it goes wrong.”


Remember that other motorcyclists may well be filtering also so rear observation, as always, is important too. Don’t be tempted to ride faster then you feel is safe because you are being pressured by a following rider or feel the need to keep up with one in front.


Be courteous to other road users, it costs nothing. Bikers have a poor image in the eyes of some non bikers and being courteous may just make a difference. Don’t get involved in wing mirror bashing or window thumping, you get wound up which makes for a less safe attitude. Drivers then get even more anti-biker and then may take it out on the next bike they meet.


So can we filter safely?


I think the simple answer to that is ‘not completely’ but we can manage the risk to minimise the likelihood of bad things happening.


So what should we consider when filtering?


Only filter if you are competent and confident to do so. It is a slow speed pastime with safety margins and views being compromised. All filtering poses risk, however, junctions, forecourts, zones of invisibility, moving lanes when others are stationary and gaps in queues are indicators of increased risk. Don’t assume anything. A flashing indicator light only means that the bulb is working.


Plan your progress; don’t just nip out into the offside lane overtaking a whole queue of traffic without having a plan of where you intend to pull back in. It may be that your plan will change as you travel down your chosen route, adapting your plans is good, not having a plan in the first place will leave you out in ‘no man’s land’ searching for the ‘thin button’.


Most important is the speed differential, by that I mean the speed of the vehicles you are overtaking against your speed. Keep your filtering speeds only marginally higher than that of surrounding road users; be ready to stop. Think about the many ‘What ifs?’ What if a driver ahead changes lane without notice, what if a door swings open in my path, what if a vehicle ‘U’ turns as I approach, what if an unseen vehicle is beckoned out of a junction or off a forecourt by a ‘helpful’ driver ahead. Have a plan and be ready to stop. Watch for subtle movements of other vehicles, drivers who intend to change lanes or move over for an approaching exit tend to subconsciously slightly move the vehicle to that side of the lane, often without even knowing they are doing it.


Space is the friend of the filterer; don’t creep along the offside of a line of traffic so close to the driver’s door you could smell the driver’s aftershave / perfume / cigarette smoke. By positioning yourself away from the vehicles you’re passing you get a better view. You can see more of the driver, that glimpse of the drivers right hand taking up a high position on the steering wheel may be all you need to avoid a ‘U’ turning taxi. By positioning wide you can also see more of the front of the vehicles you are passing, and get an early indication of a vehicle emerging from a gap or a turning on the left.


You must concentrate, the average person takes approximately 1 second from recognising a hazard to actually reacting, (thinking time) at 30mph you will have travelled approx 14 metres in that second. Then it will take about the same distance to actually stop, that’s roughly the length of two articulated lorries in total. But keep in mind that you will have travelled the length of one lorry before even touching the brakes (thinking time).


An aspect that is not always readily apparent to riders should the worst happen is how insurers and the courts will look at a variety of information before deciding upon an outcome or apportioning blame. This might be the speed and position of vehicles involved, speed and position of other traffic, the involvement of emerging vehicles or pedestrians and the evidence of any witnesses. It has not been unknown, when all of these aspects have been considered, for a filtering biker to have been found to have contributed to the cause of a collision through negligence.


A phrase I really like is, “It’s better to be a little late in this life than early into the next.”


In conclusion, keep speed down, concentrate and keep a space around you if at all possible, if in doubt wait for a better opportunity.


This is my attempt at a common sense look at some of the issues around filtering. There will be many more than space allows here. We do deal with filtering in more detail on our BikeSafe days.


Sgt Mick Cheeseman, BikeSafe-London