Liveable Streets is a seminal 1981 work, in which the urban designer and theorist Donald Appleyard that compared the experiences of people living on three similar streets in San Francisco. The main variable between the streets was different levels of car traffic: one with 2,000 vehicles per day, one with 8,700 vehicles per day and a third with 15,750 vehicles per day.

Appleyard’s key finding was that residents of the high traffic streets were less likely to know their neighbours, and more likely to feel lonely and isolated from their community. The evidence of the negative physical, mental and social effects caused by living near busy roads has only grown in the subsequent years.

Appleyard’s research led him to warn urban planners in developing nations: “Streets can kill cities.”

Poor urban planning decisions that prioritise private cars over everything else create cities that are criss-crossed by gridlocked barriers, excluding those who can’t afford motor vehicles, and where pollution belching vehicles poison the lungs of humans forced to share the streets with them. We now know that a quarter of total global premature deaths are caused by some form of human-induced pollution. Those same emissions are also a major contributor to climate change, that poses even bigger risks to human health and well-being.

It doesn’t have to be that way. Instead of choking urban life, streets can be a key resource in the fight for more liveable cities and reduced climate emissions. Streets will always serve as transport routes, allowing citizens to move around the city – yet the forms of transport that dominate those routes will determine if streets can fulfil their other key role, as centres of communities. Streets that prioritise pedestrians, bikes, buses and other types of mass transit are far more likely to be places where people want to meet, socialise, shop and live.

In many cities, streets take up about a third of the total available urban space – but this provides mayors with a tremendous opportunity. If a city manages to improve the quality of its streets by converting them into inclusive, healthy and attractive spaces, it will successfully improve a third of its land directly.

The additional benefits that flow from such a shift are remarkable: millions of pollution-related premature deaths avoided each year; economic growth from thriving communities; money saved from health budgets as public health improves thanks to more active lifestyles; less inequality between rich and poor neighbourhoods; and reduced greenhouse gas emissions.

In an effort to initiate a global shift to truly liveable streets that boost their cities, 12 mayors from across the C40 network recently launched the Fossil-Free-Fuel Streets Declaration. This commitment to procure only zero-emission buses from 2025 and make major areas of these 12 cities zero emissions by 2030, will lead the way to a more pleasant urban environment for over 80 million people.

What is so significant about this declaration is the diversity of cities that were able to sign. If Paris, London, Los Angeles, Copenhagen, Barcelona, Quito, Vancouver, Cape Town, Seattle, Mexico City, Auckland and Milan can do it – cities of vastly different size, location and history, united by their sheer will to improve the urban environment – there is no reason for any city to hold back from adopting similar people-friendly policies.


The commitment of a group of mayors who represent more than 80n people has an additional benefit in the message it sends to markets. Almost 60,000 buses operate on the streets of these 12 cities. The Fossil-Free-Fuel Streets Declaration gives a powerful signal to all vehicle manufacturers that cities are demanding emission free products and services. The future of our cities is not powered by burning fossil fuels, and any business who ignores that reality will get left behind.

This transformation is already underway. For example, London has the biggest fleet of electric buses in Europe with 170 already on the road; Los Angeles has just signed contracts to procure 95 electric buses; Copenhagen has committed to ensure all new buses will be zero emission from 2019, and in Paris 4 out of 5 buses will already be electric by 2025. In China the numbers are of a different magnitude altogether, with tens of thousands of electric buses already on the roads. Major cities like Beijing and Shenzhen will have fully electric bus fleets before 2020.

Similarly, a quiet revolution in cycling is taking place, and almost overnight hundreds of thousands of cyclists can be seen on the streets of Beijing and Shanghai. I couldn’t believe my eyes when I visited China a few months ago, but cycling is back in a big way and it is thanks to an innovation in cycle hire that enables users to pick up and drop off high quality bikes wherever they finish their journey. The young entrepreneurs behind providers of these brightly coloured bikes, such as Ofo and MoBike, are now successfully replicating the model across the world. I am sure it is going to massively change the way people travel, and our streets will be cleaner and quieter as a result.

Donald Appleyard was tragically killed by a speeding vehicle on the streets of Athens in 1982. His legacy is now being realised on the liveable streets of our great cities. Streets can kill cities. But the solution is not to try and close off our streets.

Instead, we need to reclaim streets from motor vehicles and re-purpose them for the benefit of the maximum number of citizens. That way, streets become the lifeblood of cities, and help create the inclusive, prosperous, healthy and liveable cities of the future.

Mark Watts is executive director C40 Cities.

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