How can cities make the most of the space unlocked by driverless cars?

Vroom, vroom. Image: Getty.

This summer, Oslo’s city council will give its plans to free the city centre from cars a strong push, and scrap hundreds of parking spaces. This step by local politicians is part of a wider agenda turning the Norwegian capital into the greenest and most sustainable city in Europe. Other major European cities, including Dublin, Milan, Madrid, and Paris, have announced their intention to follow the example and go car free, at least in some downtown areas.

Though converting today’s congested cities into havens for pedestrians and cyclists may currently seem ambitious, the emergence of driverless cars means it is far from a distant dream: what seemed like a vision of tomorrow’s world is now literally only a few years down the road. What driverless cars mean for urban environments is yet to be seen; but it is clear that they will offer the greatest advantages to cities with high population density.

Urban centres are the cores of economic productivity, but simultaneously the areas most hampered by road congestion, available land and environmental constraints. Autonomous vehicles have the potential to be a remedy to all three of these limitations; but they’ll require decisive and consistent policy action to do so.

That won’t necessarily mean putting legal restrictions into place: in a driverless city, changing patterns of car ownership will mean that parking spaces will simply become obsolete over time. In short, this means that carparks can be transformed and used in an economically more productive way.


This will have the greatest value in dense urban cities where space has a much higher value than in rural areas. For the 80 per cent of EU citizens living in an urban world the change will be transformative.

So it’s certain that the emergence of autonomous driving will entail a very serious review of the way we use space, road and otherwise. The process of that review offers great opportunities, not only to accommodate the needs of this new technology, but to utilise the very process, and the space liberated, to make a wider impact on improving the urban experience for all.

In this process citizens must be consulted actively so they have a stake in the way such spaces are transformed. They are the ones with the most in-depth and intimate knowledge of the particularities of private and public transport within their own communities. They are also most aware of the economic and social needs of the areas they live in. In the UK, this could mean giving citizens a greater say in drafting planning obligations under section 106 legal agreements, where investors are meant to contribute towards infrastructure or services needed for the proposed developments.

Whether freed-up space is used to extend existing houses and estates, allow new businesses to prosper, or develop leisure zones and cycle lanes will largely depend on local need. For instance, developing more green space can boost the overall well-being of citizens as a number of academic studies suggest.

Because urban planning has the greatest potential to impact their day-to-day lives, citizens are best placed to offer solutions or innovative ways to both integrate autonomous vehicles into their communities and how to alter urban space in light of the opportunities that autonomous vehicles usher in. In the long run, strategies of actively engaging citizens can help to promote social cohesion, share the benefits of new technologies more widely and reinvigorate representative democracy against the backdrop of increasing inequalities and the populist era.

Florian Ranft researches structural changes in economies at Policy Network and tweets as @FloRanft.

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How bad is the air pollution on the average subway network?

The New York Subway. Image: Getty.

Four more major Indian cities will soon have their own metro lines, the country’s government has announced. On the other side of the Himalayas, Shanghai is building its 14th subway line, set to open in 2020, adding 38.5 km and 32 stations to the world’s largest subway network. And New Yorkers can finally enjoy their Second Avenue Subway line after waiting for almost 100 years for it to arrive.

In Europe alone, commuters in more than 60 cities use rail subways. Internationally, more than 120m people commute by them every day. We count around 4.8m riders per day in London, 5.3m in Paris, 6.8m in Tokyo, 9.7m in Moscow and 10m in Beijing.

Subways are vital for commuting in crowded cities, something that will become more and more important over time – according to a United Nations 2014 report, half of the world’s population is now urban. They can also play a part in reducing outdoor air pollution in large metropolises by helping to reduce motor-vehicle use.

Large amounts of breathable particles (particulate matter, or PM) and nitrogen dioxide (NO2), produced in part by industrial emissions and road traffic, are responsible for shortening the lifespans of city dwellers. Public transportation systems such as subways have thus seemed like a solution to reduce air pollution in the urban environment.

But what is the air like that we breathe underground, on the rail platforms and inside trains?

Mixed air quality

Over the last decade, several pioneering studies have monitored subway air quality across a range of cities in Europe, Asia and the Americas. The database is incomplete, but is growing and is already valuable.

Subway, Tokyo, 2016. Image: Mildiou/Flickr/creative commons.

For example, comparing air quality on subway, bus, tram and walking journeys from the same origin to the same destination in Barcelona, revealed that subway air had higher levels of air pollution than in trams or walking in the street, but slightly lower than those in buses. Similar lower values for subway environments compared to other public transport modes have been demonstrated by studies in Hong Kong, Mexico City, Istanbul and Santiago de Chile.

Of wheels and brakes

Such differences have been attributed to different wheel materials and braking mechanisms, as well as to variations in ventilation and air conditioning systems, but may also relate to differences in measurement campaign protocols and choice of sampling sites.

Second Avenue Subway in the making, New York, 2013. Image: MTA Capital Construction/Rehema Trimiew/Wikimedia Commons.

Key factors influencing subway air pollution will include station depth, date of construction, type of ventilation (natural/air conditioning), types of brakes (electromagnetic or conventional brake pads) and wheels (rubber or steel) used on the trains, train frequency and more recently the presence or absence of platform screen-door systems.

In particular, much subway particulate matter is sourced from moving train parts such as wheels and brake pads, as well as from the steel rails and power-supply materials, making the particles dominantly iron-containing.


To date, there is no clear epidemiological indication of abnormal health effects on underground workers and commuters. New York subway workers have been exposed to such air without significant observed impacts on their health, and no increased risk of lung cancer was found among subway train drivers in the Stockholm subway system.

But a note of caution is struck by the observations of scholars who found that employees working on the platforms of Stockholm underground, where PM concentrations were greatest, tended to have higher levels of risk markers for cardiovascular disease than ticket sellers and train drivers.

The dominantly ferrous particles are mixed with particles from a range of other sources, including rock ballast from the track, biological aerosols (such as bacteria and viruses), and air from the outdoors, and driven through the tunnel system on turbulent air currents generated by the trains themselves and ventilation systems.

Comparing platforms

The most extensive measurement programme on subway platforms to date has been carried out in the Barcelona subway system, where 30 stations with differing designs were studied under the frame of IMPROVE LIFE project with additional support from the AXA Research Fund.

It reveals substantial variations in particle-matter concentrations. The stations with just a single tunnel with one rail track separated from the platform by glass barrier systems showed on average half the concentration of such particles in comparison with conventional stations, which have no barrier between the platform and tracks. The use of air-conditioning has been shown to produce lower particle-matter concentrations inside carriages.

In trains where it is possible to open the windows, such as in Athens, concentrations can be shown generally to increase inside the train when passing through tunnels and more specifically when the train enters the tunnel at high speed.

According to their construction material, you may breath different kind of particles on various platforms worldwide. Image: London Tube/Wikimedia Commons.

Monitoring stations

Although there are no existing legal controls on air quality in the subway environment, research should be moving towards realistic methods of mitigating particle pollution. Our experience in the Barcelona subway system, with its considerable range of different station designs and operating ventilation systems, is that each platform has its own specific atmospheric micro environment.

To design solutions, one will need to take into account local conditions of each station. Only then can researchers assess the influences of pollution generated from moving train parts.

The ConversationSuch research is still growing and will increase as subway operating companies are now more aware about how cleaner air leads directly to better health for city commuters.

Fulvio Amato is a tenured scientist at the Spanish National Research CouncilTeresa Moreno is a tenured scientist at the Institute of Environmental Assessment and Water Research (IDAEA), Spanish Scientific Research Council CSIC.

This article was originally published on The Conversation. Read the original article.