How the U.K. capital made car traffic scarce in some precincts — and how it changed the city
This is the first in a new monthly interview series, Borrow and Steal. In each installment, I’ll profile a different evidence-backed urban policy idea from around the world — and talk to a local who has worked to translate the idea into reality.
Our first interview is with James McAsh, a councillor in London who, since 2018, has represented Southwark — a district of about 300,000 residents on the south bank of the Thames, known for landmarks like Shakespeare's Globe and the Tate Modern. Until earlier this month, James was the council member responsible for street design across the borough, where he oversaw the scale-up of so-called “low-traffic neighborhoods,” a street management program enacted as an emergency measure to create more safe, outdoor space during the COVID-19 pandemic. Since then, James has worked to make many of Southwark's low-traffic neighborhoods permanent. And James has become an advocate for rolling out the concept to other cities, like New York, where there is a nascent movement to replicate London’s scheme. (Open Plans, a local street safety group, has advocated for five low-traffic neighborhoods in every New York City borough. Recently, Queens Community Board 6 [Forest Hill and Rego Park] voted to request the Department of Transportation stage a local low traffic neighborhood pilot, while Manhattan Community Board 8 [Upper East Side] rejected a similar measure.)
In this interview, James explains the low-traffic neighborhood (LTN) concept and shares insights from London’s experience. We dig into costs and benefits, including data on safety and congestion impacts, and the politics of rolling out low-traffic neighborhoods. James concludes with advice for other cities considering this as a strategy to create more livable streets.
The following conversation has been condensed and annotated for clarity.
Cara Eckholm: To kick us off: what is a low-traffic neighborhood exactly? And how does it relate to other, perhaps better-known, urban planning concepts, like the 15-minute city?
James McAsh: A low-traffic neighborhood is closely connected to the concept of a 15-minute city. You start by defining a neighborhood by its main roads — what we call boundary roads. Those boundary roads should be the routes built to handle higher volumes of traffic. You essentially draw a line around the neighborhood.
Inside the boundary, the goal is simple: no through-traffic on residential streets. That doesn’t mean the area is pedestrianized — cars can still enter — but you can’t cut through. If you want to get from one boundary road to another, you have to go around on the boundary, not straight through the neighborhood. Every home and business is still accessible by car, but every car journey inside the neighborhood starts or ends there, which dramatically reduces traffic. There's no reason why someone from outside should be driving through residential streets.
Cara Eckholm: To address the boogeyman in the room — how do you deal with parking?
James McAsh: You can keep parking exactly as it was. You might lose a small number of spaces to install infrastructure — usually because you need turning space near the barriers used to block cars from entering — but we’re talking a few spaces here and there, not major changes.
Cara Eckholm: So if I’m a resident with a car, and I previously had a parking space, I’m keeping it. The difference is that people who were cutting through on their way to an alternate destination can’t anymore. Is that right?
James McAsh: Yes, exactly. In some ways, LTNs would work better for U.S. cities than U.K. cities because you have the grid. With the grid, it’s easier to define a clean box bounded by major roads, which cars can no longer cut through.
The main tool to block passage is a modal filter, which is just a technical term for something in the road that blocks certain modes of transport. The simplest version is a planter or bollards placed so pedestrians and cyclists can pass through, but cars can’t. You can also do it with camera enforcement: the street stays open, but if you drive through, you get a fine.
Cara Eckholm: How prevalent are low-traffic neighborhoods in London? My understanding is that London introduced congestion pricing in 2003 — but that the LTN push is more recent, and stemmed partly from experimentation during the pandemic.
James McAsh: That's mostly right. The phrase low-traffic neighborhood was popularized in 2020. But actually, if you think about what a low-traffic neighborhood is, it's a quiet residential street where you can't drive through. Those have existed all across the world, including in London, for a very long time. Think about a cul-de-sac. Or social housing projects — they are rarely designed for people to drive through them.
But yes, in 2020, we had a big leap forward. People went from talking about low-traffic neighborhoods to executing them. Social distancing exposed how narrow sidewalks were on routes that people depended on. At first, we did some sidewalk widening, but LTNs were also a way to redistribute space — not banning cars entirely, but shifting street space toward walking and cycling.
[Note: While estimates vary, there are now at least 80 known LTNs throughout London.]
Cara Eckholm: How many LTNs did you roll out in Southwark?
James McAsh: In Southwark, we did about a dozen. The 2020 rollout was reactive. We put several in quickly, pulled a few back, and have since expanded others. It was driven by demand and which local politicians were keen.
It was great that we were able to have this big jump forward, but the speed of execution created some tension. If you don’t design boundary roads carefully, you can displace traffic onto nearby residential streets, and, understandably, the residents who live on those streets are upset.
Now we’re doing things more holistically: mapping the borough’s main strategic routes first. Inside them, we’ve identified about 25 zones that could become LTNs; all 25 are designed so implementing one won't make a mess next door.
Cara Eckholm: Do you have a sense of how much traffic in these areas was cut-through traffic versus residents driving locally?
James McAsh: It varies massively. But I’ll give you a contrast. We did one in Dulwich — which is in the south, further away from the center. It's more residential, affluent, whiter and has higher car ownership. And we did one in Walworth, which is very inner-city. It’s ethnically mixed, lower income, much lower car ownership.
Residents’ experiences in both neighborhoods reflected their relationship to cars. If you live in Dulwich, you probably drive, so you feel the route change immediately — some liked it, many did not. Whereas, in Walworth, many people walk, take the bus, or cycle. So traffic feels like an external force imposed on you. Making your kids choke, taking up space, and creating noise pollution. So people generally had a positive reaction when traffic was removed.
[Note: As a comparable, one study in New York found that the majority of driving on residential streets in most Community Districts was cut-through traffic.]
Cara Eckholm: You started to get into the politics of deciding where LTNs are placed. How does an LTN actually get approved and implemented?
James McAsh: In 2020, our process for approving LTNs was very request-driven, but we saw the inequity and tensions that created. Now we’re trying to ensure every part of the borough has an opportunity, paired with community engagement about what people actually want.
The physical infrastructure is cheap — planters, bollards, benches. You start with the basic measures, then once the pattern is established and people are using the newfound space you can do lots of really exciting things. Like creating space for kids to play.
Cara Eckholm: And the borough pays for it?
James McAsh: Yes. And we introduced a prioritization framework. At the center were deprivation, air quality and the number of people who’d been killed or seriously injured in collisions. So we focused on places that are dangerous, polluted and home to disadvantaged communities.
Cara Eckholm: What should other cities expect in terms of cost?
James McAsh: The bare bones — planters — are in the tens of thousands of pounds. Once you move into beautification and making it permanent — public realm upgrades — you’re in the hundreds of thousands. Even a relatively big LTN usually isn’t more than a million pounds.
[Note: A recent study by a trio of U.K.-based academic researchers found a per-person cost of £28-35 for LTNs implemented during 2020 as emergency interventions, or £112 for higher-cost, permanent LTNs. It estimated over £1 billion in health economic benefits on a program cost of £100 million.]
Cara Eckholm: The staggered nature of the rollout created natural experiment-like conditions, which seems to have offered a really fertile ground for transportation research. What does the data say?
James McAsh: The strongest data is London-wide. Inside the new low-traffic neighborhoods, there were 50% fewer casualties than there were before. And importantly, there was no increase in casualties on boundary roads, which is the common criticism.
We also saw that 74% of the streets within LTNs have reduced traffic. One figure I’ve seen is median traffic falling from roughly 1,200 vehicles a day to around 650 inside LTNs.
Some impacts are less expected. There’s some preliminary evidence of lower crime in LTNs. I think there's a lot of potential for exploring why that might be the case.
And we’ve also heard concerns about emergency response times — especially from fire services — but the evidence suggests response times remain the same. People notice the moment a vehicle hits a barrier and has to reroute, but they don’t notice that the rest of the trip is faster because there are fewer cars on the road. And if you use cameras instead of hard barriers, you can build in exemptions for emergency vehicles (or disabled drivers). All of a sudden they're on roads that have much less traffic, which can actually make motor vehicle trips faster.
Cara Eckholm: To play devil’s advocate: You haven't seen any drawbacks? What's the case against LTNs?
James McAsh: The key downside is a feature, not a bug in my view: Short car trips inside the neighborhood become harder and slower. That is intentional. We want to reduce those kinds of journeys.
But unfortunately, some people do get caught in the crossfire. Maybe they've got lots of kids or they're plumbers or they're moving a piano or something like that. They need a motor vehicle. They can't do it on their bike. So that is a downside. They can still make the journey, but it may become longer because they have to go out to the boundary roads and loop around.
Cara Eckholm: What distance does an LTN typically cover?
James McAsh: Something like one to two miles, probably, at the upper end. You’re not talking about huge areas. The reason it connects to the 15-minute city is that the neighborhood should be walkable — how big it is depends on the road structure and specifically where you have boundary roads that can handle large volumes of traffic. But 15-minutes walking is about right.
Cara Eckholm: The 15-minute city has been heavily politicized, as have LTNs. My understanding is that conservative MPs are generally opposed to LTNs, and your former prime minister, Rishi Sunak, ordered a review of the program, which created tension with London Mayor Sadiq Khan, who’s set a goal for 80% of all trips in the city to be done by bicycle or public transport by 2041. How did LTNs get caught up in national politics?
James McAsh: It very much became tied up with a broader culture war and with conspiracy theories. In the U.K., often, low-traffic neighborhoods and the 15-minute city are used synonymously. They don’t mean the same thing, but in the discourse, they’re sort of used interchangeably. And there’s this conspiracy theory that we are putting in all these cameras so that eventually you will need a pass to get out of your neighborhood to go to a different neighborhood.
Cara Eckholm: Wow, that’s more nefarious than I was expecting.
James McAsh: Yeah, I mean obviously, that is far from the truth. Local government is nowhere near efficient enough to manage something like that! Now to be clear, Rishi Sunak isn’t a conspiracy theorist, but the “war on the motorist” is something that Sunak pushed — the idea that woke councils like Southwark are going to war with good working people who need their car to drive.
So he did call for a review. The hook was that the 2020 LTNs were implemented without consultation — considered an emergency measure during the pandemic, with consultation only afterward.
Actually, when the evidence came back, it suggested that LTN’s achieved their policy objectives and that they are popular with the majority of residents.
The national debate has cooled down now. And we have a new Labour government. They’re not evangelical about LTNs, but they’re also not against them. They’re mostly leaving councils alone. Progressive councils do them, less progressive councils don’t.
Cara Eckholm: Is this mostly a London phenomenon? I am thinking about the congestion pricing analogy, where you haven't really seen a replication effect outside of large cities.
James McAsh: It’s a very London-centric project, but that’s not to say it’s just London. Oxford, which is a much smaller city, also has quite developed low-traffic neighborhoods, and there are a few others dotted around the country.
One difference is that congestion pricing needs scale to work and has high setup costs. In theory you can have a low traffic neighborhood in a pretty small town. A town of 20,000 could have a low-traffic neighborhood.
Cara Eckholm: What was your experience like rolling out LTNs in Southwark? What were you actually seeing on the ground in terms of the community's reception?
James McAsh: We’ve learned lessons and hopefully your readers can learn from our mistakes as well.
We’ve essentially found that you’ve got this curve: At first, the only people who know about LTNs are those pushing for them. As an elected representative, your inbox is full of support. It feels very positive.
Then it’s announced and popularity really, really drops. The protestors come out. With most political issues, you can say “this is a systemic problem” — but an LTN is clearly a political choice with your name on it. It can feel like you’re under quite a lot of pressure at that point.
Cara Eckholm: Were you panicked?
James McAsh: I wasn’t panicking, but I was new to this and didn’t have the research I have now.
The downsides of a low-traffic neighborhood are experienced immediately. You could previously take a route, bollards go in and now you can’t take that route.
The upsides take longer. It takes a while for that mom to realize there’s a new route she can walk with her kids, traffic-free. She won’t know the route is there immediately. Then when you start adding infrastructure like little parks, the benefits are clearer, but that takes a while to come through.
So when implementing schemes like LTNs, you do have to steel yourself, be prepared for a lot of negativity, and understand that there is a cycle. You also need to set clear expectations on what your success criteria are and be honest about what you can and can’t measure. Air quality is a good example: Hyperlocal air quality data is hard to measure, even if broader trends are positive.
Cara Eckholm: Have the LTNs that were rolled out during the pandemic stuck?
James McAsh: None were removed. Some were adjusted — rolled back slightly — but they stayed. The big shift now is moving from emergency implementation toward high-engagement, more deliberate design.
The one I worked on most recently is in the central part of the borough. The area includes the Tate Modern and Tower Bridge, and has high population density, low car ownership and lots of tourists. We recently did early engagement with multiple proposals — street closures, modal filters — and every proposal had majority support. In fact, the main feedback was to be more ambitious. More modal filters.
Cara Eckholm: What should other cities take away? Do LTNs need to come after congestion pricing, or can they be a line of first defense?
James McAsh: I’d treat them separately. I support congestion pricing and it covers a bit of my borough, but it actually doesn’t overlap with the 2020 LTNs we introduced — it's a different geography. So if you don’t have congestion pricing, LTNs can be a strong tool in their own right.
The biggest lesson is that early engagement is really important. You need to know what's happening on the ground. The best example is your conversations with local businesses. Businesses often say, “If you ban cars, I’ll go out of business — my customers drive.”
So now we don’t start with business owners. We start with customers. We stand outside shops and ask: How did you get here? Usually, it’s overwhelmingly walking, cycling and transit. Then we go to the business and say: This is how your customers already arrive, and we’re going to make that easier.
Cara Eckholm: Do you have a team of ethnographers who go out and do this research? The type of engagement you are describing is pretty different from what we usually see in the U.S. — a community board meeting where people show up to lodge their support or their complaints.
James McAsh: In Southwark, the engagement process I introduced has five stages.
Stage one is simple: We ask residents across the whole borough, what do you want on your street? Do you want more trees? A pedestrian crossing? People can tick boxes and show us on a map. The goal is to gather early, grounded data.
We also want to make sure the responses are representative. The typical approach in the U.K. is an online portal and maybe a few meetings at a library. Instead, we track response rates street by street across the borough. If a street had less than a 20 percent response rate, we knock on doors. That helps us reach people who are less likely to participate.
Stage two focuses on individual zones. We go back to residents with some initial ideas and ask: What do you think of these proposals?
Stage three is when we present a full scheme. We show exactly what the area will look like — what routes might change for drivers, where public space will improve, where we might add planting, small parks or play areas.
Stage four is a statutory consultation — a formal public hearing, where people can lodge support and complaints. At that point, the scheme is essentially fixed. It’s largely a yes-or-no moment.
Then stage five is evaluation. We measure the project against the criteria we set at the beginning and give people the chance to say whether it’s working and make tweaks.
Cara Eckholm: And in terms of your role in this movement, you just wrapped up your term overseeing street design in Southwark. What's next for you?
James McAsh: We have elections coming up and I’ll be running for re-election. Beyond that, I’m talking to people and looking for where I can make the biggest impact — especially on sustainable travel and cities.
