All about filters

As I type this, we’re in the middle of a consultation about the design of the Capel and Woodgrange Low Traffic Neighbourhoods. I have been chatting to officers, colleagues and residents about it, and am in touch with people who are in favour, those who are against, and every kind of variation in between.

One thing that has come up a few times is the question about a permits system for local residents, and this made me think that it might be useful to spend some time writing a blog post about the different types of ‘filters’ that can prevent through traffic, as each has its own pros and cons.

If you’re new to the idea of a Low Traffic Neighbourhood, you can read my blog post about them here, which introduces the concept.

A ‘filter’ or ‘modal filter’ is so-called, as I belatedly realised, because it filters the types of movement it allows through it. The most common LTN filters will filter the through traffic to allow people on foot, travelling by wheelchair, or people riding bicycles to move through them freely, but restrict motor vehicles to other routes, largely on main roads where possible.

The ultimate filter: cul-de-sacs

Maybe I am being a bit facetious here – people don’t normally consider cul-de-sacs modal filters. But actually part of the reason Newham scores relatively highly on some assessments for healthy streets is that our ‘LTN’ percentage is strangely high, which I believe is due to the cul-de-sacs that make up some of Beckton (as well as a number of our older housing estates that were designed originally not to allow through traffic, effectively along LTN principles).

The ultimate filter to through-traffic is a road designed as a cul-de-sac. The only vehicles within this dead-end will be those who belong to people who live there, or those that are specifically visiting those addresses. There is one way in, and one way out. Modern transport planning doesn’t tend to create cul-de-sacs for a variety of reasons, but I think that one of them is that they’re not particularly friendly to walkers. You might live geographically very close to a house in a neighbouring cul-de-sac, but have to walk all the way out of yours, onto the main road, and back into the next one in order to visit them ( to illustrate this to Forest Gates, for example if you live at the end of Curwen Avenue in Forest Gate, the homes on Horace Road are mere seconds away from you as the crow flies, but if you’re not a crow, walking there will take you the opposite way back out onto Woodford Road first.)

Fixed bollards / physical blockages

There are lots of these kinds of filters around, and I sometimes refer to the older ones as ‘invisible filters’ because once they have been in place for a while, people tend not to even notice that they are there, but just adjust how they move around them. At the end of the proposed Capel LTN is a filter on Anna Neagle Close / Brownlow Road, and in 8 years of being a councillor I have received precisely no requests that this should be opened back up to vehicles. In fact, quite the opposite: we had to install an extra bollard when it turned out some cars were squeezing up onto the pavement and illegally driving through.

Other older filters that local readers might recognise: Richmond Road E7, the junction of McGrath Road and Forest Lane, Buxton Road E7, and there is a whole twitter thread including many more, which my friend and colleague John Morris posts here:

The benefits of a complete physical block are that they make the most difference to the quietness of the streets behind it. On roads that were previously busy with traffic cutting through, they create a real sea change: the volume of traffic drops so significantly that pedestrians, instinctively, know they are safer and will behave differently on the road. Children might play on it, more nervous or vulnerable people on bikes might cycle on the road rather than the pavement. People might walk down the middle of it. I’m sure there’s some good research somewhere about traffic volumes and behaviour change, but in order for people on foot and particularly more vulnerable road users to physically reclaim a street for walking, there needs to be a real quietness that you can not just count, but feel.

Another benefit is that the physical barrier can take many forms. A common one for more recent or for experimental filters is a wooden planter, which can contain plants to encourage pollinators and small trees. More established filters can include a physical ‘build-out’ into the road, with bicycle parking, a pocket park, tree planting, planting for better drainage to reduce flooding risk, or more.

The downside of this kind of filter is that the physical restriction is absolute. Some older filters only have narrow spaces that some adapted bicycles or cargo bikes cannot get through. People carrying a larger load on a bike might need to squish past older bollards. Emergency services vehicles also cannot get through and will need to use the usual access points.

Lockable bollards

Some filters have bollards across the road which are padlocked in place, and can be opened with a key by emergency services for fast access.

The advantage here is pretty obvious: emergency services vehicles that cannot take the normal route into the road can open up the filter, and gain access more quickly if needed. So you get all of the radical advantages above of much quieter roads too. That is, until..

The major ‘con’ here is vandalism and misuse. One local locked bollard filter is unlocked and the bollard moved so frequently that a local resident appointed herself as an unofficial bollard watchperson and emails me to let me know whenever it happens. It seems that someone nearby somehow got hold of one of the keys, and was unlocking the bollard whenever they wanted to drive through, in effect creating their own one-person exemption scheme. Every time a padlock is lost / the bollard is damaged / the bollard is lost, then someone is dispatched from Highways to fix it, which all comes at a cost that we all pay for through our Council tax.

Another downside, although not a game changer, is that in contrast to pocket parks, and trees as above, metal bollards are not desperately attractive, and aren’t as positive an addition to the local environment. (There are some filters that combine the two, with some planting, and perhaps one removeable bollard in the middle, and to a certain extent overcome this last drawback.)

‘Open’ filters – camera enforced

This kind of filter is a legal restriction on access at a certain point, combined with signage, perhaps with something like a planter providing a part-barrier in the road as a visual reminder, and with an ANPR camera installed to issue tickets to those people in cars who drive through anyway.

The benefit of this is that it does allow some access for, eg, refuse vehicles or emergency services vehicles (see more about exemptions below). I’m personally instinctively not as in favour of these types of filters, for a few reasons.

The main one is that people in cars and other vehicles will SO consistently ignore or misunderstand the signage, no matter how much there is, and simply drive through. Of course every vehicle in contravention will provide some revenue, which can be used for more road improvements. But ultimately the purpose of these kinds of schemes is actually to create safer places, and to encourage walking and cycling, not to raise money. And these aims are not achieved when cars simply drive through junctions that have been identified as modal filters to be closed to through traffic. The roads that should be much quieter are less quiet. People driving through filters either knowingly or in error are more cross because they believe they have been duped into getting tickets. It’s less safe to walk and cycle. Every vehicle that gets a ticket weakens the success of the scheme.

But that said, liaising with people including the emergency services is an important part of designing any LTN. And sometimes people from the fire service, police and ambulance service prefer these kinds of modal filters, or require them in particular locations, so I do recognise that in many places these are the best that we can do, and still do make a difference.

‘Open’ filters with exemptions

Some modal filters have some exemptions. These vary considerably, even within London, from borough to borough and from location to location. But to give an idea, exemptions could include refuse trucks (often exempted because they are such large vehicles with large ‘turning circles’), emergency services vehicles, black cabs, all private hire vehicles, blue badge holders who are local residents, all blue badge holders, local residents of that road who own a car, or local residents who own a car within a certain distance of the filter. I’ve also heard people advocate for (although I don’t think I’ve seen these in place) exemptions for all NHS workers, for community NHS workers, care workers, public sector workers, tradespeople, people who work in the area, and other groups.

As you might be able to tell from the list above, one of the main disadvantages to issuing permits or exemptions is deciding who should get them. There are arguments for and against each of the groups above, some very passionately held, and including any group in an exemption does strengthen the argument that other people should also be exempt.

This then in turn adds to the disadvantage above: the more vehicles that are exempt, the more diluted the impact of the scheme is.

But specifically in terms of permits for local residents, I think there are some additional factors to consider. LTNs have two main aims, which are really nicely laid out in the leaflet that went to all homes within these proposals.

Key objectives

The primary project objectives are in line with broader Newham Council policies.

OBJECTIVE 1 – Remove through traffic

To create a safe environment that has low levels of motorised traffic, where the widest range of people feel comfortable walking and cycling.

OBJECTIVE 2 – Encourage modal shift

To encourage people to walk and cycle for local trips, rather than drive.’

‘Woodgrange and Capel Low Traffic Neighbourhood, Jan 2023, London Borough of Newham

Permits for local residents who own cars means that there is no necessity for people living within the LTN to change how they move around. Without permits, as per the LTN design and intentions, people living within as well as outside the LTN can still access anywhere they want to by car, but they might have to change the route they choose to get there. With permits, people inside the LTN who own cars can carry on as before, and the onus to change behaviour falls only on those outside it. I worry about this in terms of community cohesion, and think any barrier created between people eligible for permits and those not could be very damaging and divisive*.

I speak from some experience, although not in my ward. When local councillors, the Mayor, and others (including me, in my then role which included Highways across Newham) looked at huge problems caused on Stanley Road in East Ham by volumes of traffic that the road was never designed for, we realised that closing Browning Road bridge to through traffic would in effect create a mini LTN in the area bounded by Shakespeare Crescent. A system of permit exemptions for local residents was agreed, and was enormously controversial. In fact, a protest on the day of opening resulted in an extension of the exemption area, and even now the closure is constantly ignored by drivers who are then fined, and is cited in unfavourable news articles as being a ‘cash cow’ – precisely for all the reasons I have outlined above.

I also suspect that exemptions existing for this Browning Road filter contribute to some confusion: that other drivers see someone driving through, think to themselves, ‘oh it must be ok’, drive through themselves and then get a fine.

There are of course exemptions available for residents who live on school streets, but this is is somewhat different, because without those local permits, people who live on school streets who own a car would be completely unable to use it during the times of the closure. The overall impact on the school street is small because the area of closure is small, and so the volume of entirely local traffic is very small, meaning that the streets are used by parents, carers and children to walk and cycle, and cars proceed only occasionally and with caution. Just as a reminder, within an LTN every home and business is still accessible by car, it just might require someone arriving by car to change their route. (If this isn’t the case, then please let highways know.)

Another important point is something that the officers pointed out to me when designing this LTN, and weighing up different filter locations: there is a direct trade-off for local residents between how close they live to a filter and the extent of the benefits they will experience. Some residents with cars who live very close to a filter may experience more disadvantage as they need to change their preferred route more, but the corollary to this is that they also experience maximum benefit as their road, and indeed their part of the road, is particularly quiet, pleasant and safe.

I also do want to add, again that not all Newham residents own cars. Providing exemptions for those that do would dilute the benefits for everyone, including those who do not have a car (who are more likely to be poorer residents). Although car ownership is higher within these two proposed LTNs than elsewhere in Newham, I think that the higher levels of car ownership is even more of a reason to create LTNs that encourage all car owners, including me and my family, to use their cars less whenever it’s possible to do so.

So all this to say that although I am personally somewhat persuadable, depending on location, about the merits of fixed or open filters, I am on balance not in favour of exemptions for local residents. Not that this decision rests with me! I wouldn’t want to give that impression. As a local councillor I’m consulted by highways about the process, and will feed into it, represent local insights and concerns, and advocate for the area, but I don’t and wouldn’t expect to have a final say on the scheme overall or on any details from it. But I hope that this post has given an insight into my starting point, where I am coming from, and why.

*Talking of divides, I have heard some people say that they think LTNs create divides, and I am not sure that my experience bears this out. I currently live just outside one of our existing LTNS, which has been in place for a couple of years now. In fact, if anything that area is much more porous and accessible to me now than it was before. I travel through there by bike much more often, walk more often too, and visit local businesses in there more now that the roads are so markedly quiet. I’m always keen to understand more about how we make streets healthier, and I’m very open to understanding upsides and downsides, but I know that research backs me up on this: people know their neighbours more, and make more local connections on streets that have less traffic.

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