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Are you interested in car free cities?
Our debate today works with the article titled Car free cities: Pathway to healthy urban living from 2016, by Mark J. Nieuwenhuijsen and Haneen Khreis, published in the Environment International journal.
This is a great preparation to our next interview with Lior Steinberg in episode 396 talking about the idea of a car free city.
Since we are investigating the future of cities, I thought it would be interesting to investigate our urban environments without cars. This article examines the global transition of urban centres toward private car-free models to improve environmental and public health outcomes.
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Welcome to today’s What is The Future For Cities podcast and its Research episode; my name is Fanni, and today we will introduce a research by summarising it. The episode really is just a short summary of the original investigation, and, in case it is interesting enough, I would encourage everyone to check out the whole documentation. This conversation was produced and generated with Notebook LM as two hosts dissecting the whole research.
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Speaker 1: If you look at any major city today, I’m thinking Hamburg, Oslo, Madrid. You see this accelerating push to create zones that are well partly or even fully private car free. Now these policies are usually sold as a way to fight climate change or tackle that soul crushing congestion. But the real story, the compelling mandate for moving fast lies in the promise of profound public health gains. So the question we have to confront is this, are these anticipated health benefits? A certainty that demands immediate widespread action, or is the magnitude of these gains being frankly oversold? Potentially masking some unquantified negative risks and huge complexities in how they’re implemented. I’m going to argue that the evidence is clear. Our immediate and long-term health really depends on fundamentally shifting away from private car dominance in our cities.
Speaker 2: I hold a different perspective. Look, the aspiration to build healthier cities is absolutely necessary. I agree. But the actual citywide long-term health impact of these frankly radical policies remains highly uncertain. We risk enacting policies based on these localized, maybe temporary successes that might just falter when you try to scale them up. So I argue we must proceed cautiously and rigorously evaluate all the potential socioeconomic externalities, the equity concerns, and the significant political challenges before mandating any kind of rapid, large scale implementation.
Speaker 1: Okay, so let’s start with the current cost of the status quo, because it’s catastrophic. Private car mobility is a primary source of systemic morbidity and mortality, and we’re not just talking about the obvious trauma globally. Motor vehicle crashes account for something like 1.3 million deaths and a staggering 78 million injuries every year. We’re talking about the silent killers embedded in the system, the promotion of physical inactivity. Which contributes to about 2.1 million deaths annually, and the constant barrage of environmental exposures like noise, and of course, localized air pollution. When cities move away from car dependence, the immediate benefits are tangible. We’ve seen evidence from temporary car-free days showing impressive drops. I mean up to a 40% reduction in nitrogen dioxide. NO two, which is the pollutant tied directly to vehicle exhaust, that massive reduction in traffic related exposure. It translates directly into fewer respiratory issues and lower premature mortality. But the real systemic game changer is the opportunity to increase active mobility. We have an opportunity to bake physical activity, walking, cycling, using public transit into daily routines. Just think about the physical space. Up to 70% of downtown land in some American cities is consumed by cars and parking. Removing that infrastructure frees up vital public space for greenness, which is proven to improve longevity and mental health. Car-free policies are fundamentally resetting a system that is actively designed against human health.
Speaker 2: I see why you emphasize those catastrophic costs, but let me introduce a note of caution regarding the predictability and the certainty of the benefits you cite. While temporary results like a 40% drop in NO two on a Sunday are compelling, extrapolating those gains to a permanent citywide policy is where the data gets shaky. We need comprehensive Health impact assessment, HIA, modelling a tool that rigorously predicts how these large scale policy changes will affect population health. And the truth is. We just lack the long-term data for citywide permanent exclusion zones. One of my primary concerns, which we’ve seen in localized traffic restriction studies is this phenomenon of traffic detouring. If you restrict vehicles in the city centre, the motorized traffic doesn’t just vanish. It often gets diverted to adjacent roads and neighbourhoods just outside the car free zone. This means we risk simply moving the problem, the noise, the congestion, the pollution to less affluent, less politically represented areas, rather than decreasing it overall. And furthermore, we have to be precise about the air quality benefits. The London congestion charge is a great example. While it did reduce the number of vehicles in NOX levels, there was no observed impact on PM 10 levels. PM 10 is that course particulate matter that gets deep into the lungs. And crucially, a lot of pm 10 comes from non-US sources, things like brake wear, tire abrasion, road dust, which traffic reduction alone doesn’t entirely solve. So this suggests that restricting cars only targets exhaust components, leaving significant air quality issues untouched, especially if commercial vehicles and buses are still operating. If the air quality gains are inconsistent. Your entire justification seems to rest on physical activity, which brings us to who actually benefits.
Speaker 1: That’s an interesting point. On the non-US pollutants, though, I would frame the hierarchy of benefits differently. I agree that air quality improvements are complex, especially managing particulate matter from non-US sources. The strongest, most resilient argument for car-free cities is exactly that systemic shift toward physical activity and the cascade of co-benefits. It creates HIA modelling that analyses modal shifts. Even if only say 20 to 40% of car journeys are replaced by cycling or walking consistently shows that the single largest health dividend comes from the physical activity gain realized by the individual making the switch. The risks that come with a short increase in air pollution exposure or a minor accident risk for the active commuter are consistently outweighed by the massive reduction in the risk of cardiovascular disease, dementia, and type two diabetes. We are moving from a mode of transport that promotes a sedentary high risk lifestyle to one that promotes a low risk active one. That is a foundational health intervention.
Speaker 2: This is precisely where the concept of a community-wide benefit starts to break down. If the overwhelming health driver is individual physical activity, then the benefits are highly concentrated, aren’t they? They’re only among the minority who successfully switched to active commuting. What about the majority of the population? We have HIA studies modelling that exact 20 to 40% modal shift that indicate the health benefits from air pollution reduction in the general population are surprisingly small, as we just discussed, heavy goods, vehicles, public buses, non-US pollutants. They all remain. If the general population sees only negligible air quality improvement while traffic is displaced and access is complicated, then the policy stated goal of a massive overall community health benefit is inherently limited. You are asking for rapid disruptive change based on benefits that are concentrated in a self-selecting active subgroup.
Speaker 1: I think you’re understating the value of correcting what is a monumental market failure. While we focus on the concentrated benefits of physical activity, we cannot ignore the staggering economic waste of the status quo. The total bill for traffic congestion, pollution, and accidents across the EU member states has been conservatively estimated at what, 502 billion euros per year. That money is being extracted from our economies by a failing transport system. So moving away from the private car is a fiscal and economic correction. We haven’t given enough weight to the benefits of reclaiming space. Even if the immediate reduction in regional air pollution is modest, the policy frees up vast amounts of urban land to pursue other proven health interventions. When you create space for surrounding greenness, street trees, sidewalk, vegetation parks, you are introducing psychological restoration and stress reduction. Those are vital public health gains regardless of ambient air quality levels.
Speaker 2: I’m sorry, but I just don’t buy that. The economic and health benefits automatically outweigh the immense political and logistical costs of the transition, especially when it comes to equity. You correctly identified that the current system causes inequalities, but the transition itself poses a severe risk of creating new ones. If these car free zones are prioritized in wealthy service essential areas, they increase difficulties for lower income populations who live outside the core and rely on cars to access decentralized goods, jobs, and specialized medical facilities. Car free zones without perfect immediate public transport replacements can become areas of social exclusion, especially if traffic detours as we expect into less politically powerful, non-affluent neighbourhoods concentrating noise and exhaust exposure there. We need site specific high resolution epidemiological studies before implementation to map traffic changes and pollution exposure risk to ensure we don’t just transfer the burden of illness to the most vulnerable.
Speaker 1: The political resistance is immense. I grit you that, but the argument that current car infrastructure promotes social inclusion is simply incorrect. Studies have shown that people living on high traffic streets have significantly fewer friends and social interactions than those on low traffic streets. The noise, the danger, the physical barrier of traffic actively fragment social capital. Conversely, expanding public transport is shown to strengthen social capital for disadvantaged groups by guaranteeing access and opportunity. The policy prescription here isn’t a simple ban. It’s systemic replacement. The key is coordinating the car restriction with simultaneous, massive investments in public transport networks and comprehensive safe cycling infrastructure. That packaging of policies is what ensures accessibility for all groups and is the only credible way to reduce inequality during the transition.
Speaker 2: We must also be realistic about the timeline. Your argument for rapid immediate implementation clashes with political reality. Systemic change is agonizingly slow. Even the celebrated success story of Copenhagen took four decades of incremental policy shifts to achieve its current state. We cannot ignore the formidable political and economic forces array against this. The motor lobby is globally powerful. They actively resist any measure restricting car use. We’ve seen them successfully delay, dilute, or even cancel proposals for car-free zones in major European cities. They also fight hard against emissions regulations. This active sustained political friction means that the long-term political commitment needed for systemic rapid policy change is highly challenging. You are asking for an immediate policy mandate that the existing political framework is almost designed to sabotage.
Speaker 1: The speed of change is a hurdle, yes, but the payoff for urban vitality is revolutionary, and it provides a powerful counter narrative to the motor LO’s arguments. Let’s talk about that space again. A standard parking space demands what, 13 to 19 square meters of prime real estate. Think of the opportunity cost. That same area can fit 20 bikes or more importantly, it can become a public square, a playground or green infrastructure. Freeing up this space doesn’t just benefit health and social capital. It offers a competitive economic advantage, liveable cities with attractive public squares and green environments. They attract highly educated professionals in innovative businesses. We are unlocking economic development by making cities fundamentally better places to live. A benefit that far outweighs the immediate political headache of implementation.
Speaker 2: You cite liveability, but we have to protect local economies during this transition. While it’s often argued that Pedestrianization boosts retail sales. And there is evidence that people who walk often spend more than drivers. This evidence typically applies to partial pedestrianization schemes or public space improvements, not total bans. The data surprisingly scares for fully car-free zones that exclude all private access entirely. The concern that lost access for customers and delivery vehicles could damage certain business sectors in a total exclusion scenario is a genuine risk that remains well speculative before mandating the shift. We need rigorous quantification. Part of that HIA modelling to prove we aren’t damaging small local economies in the pursuit of these otherwise uncertain community-wide health benefits,
Speaker 1: but that risk is speculative. Whereas the cost of the existing system is certain and quantifiable, we are trading a clear, immense economic and health burden for a transition that carries risks that can be managed through smart, coordinated policy specifically around logistics and delivery infrastructure. The fear of damaging retail has historically slowed progress in every successful pedestrianization project from Copenhagen to New York. That fear has routinely been shown to be unfounded once the public space is made appealing. We are talking about using public space, which is currently dead space for parking to create a destination that draws people in, increases foot traffic, and improves the overall quality of life. The psychological benefits alone derived from reducing visual stress and noise pollution contribute directly to a city’s competitiveness. The health benefits are too large to defer action simply because of political resistance or the need for slightly more granular economic modelling. We have enough evidence today to move forward.
Speaker 2: I disagree that we have enough evidence to mandate rapid large scale policy. In summary, while the vision of a healthier car-free city is deeply appealing, the current evidence primarily supports the potential of these changes rather than the certainty of broad health gains across the entire urban population. We have demonstrated that the benefits are concentrated heavily in physical activity. For a subgroup, while the air quality gains for the general population are often disappointingly small due to residual pollution sources and non exhaust PM 10, so we must prioritize rigorous site-specific epidemiological studies and sophisticated HIA modelling to fully understand the effects on health, especially regarding pollution variability. The impact of traffic detouring. If we implement these policies too quickly, we risk exacerbating socioeconomic disparities and failing to achieve the comprehensive community health benefits we all desire. Prudence driven by thorough evaluation is paramount,
Speaker 1: and I maintain that the health imperative is overwhelming and mandates accelerated action despite the acknowledged political and logistical hurdles. The fundamental drivers for this change, combating sedentary behaviour substantially reducing critical environmental exposures like noise and localized exhaust, and most powerfully unlocking vast amounts of public space for vital green infrastructure and social interaction. Make this systemic shift. The only viable pathway toward healthier, more resilient urban living. The goal is to secure the necessary coordinated political and logistical commitment now recognizing that the substantial co-benefits far outweigh the managed risks of transition.
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