The Clean Air initiative on Church Street Bangalore, delivered by DULT with support from the UK Connected Places (CPC) and Energy Systems Catapults has been grabbing headlines since it launched in November 2020. The pedestrianisation of the thoroughfare is intended to improve the quality of life in the area and stimulate commercial opportunities. So far, the reception from shoppers, residents and business owners has been positive. How can the momentum be maintained? What can be learned from other cities around the world which have implemented similar policies?
The Air Quality Imperative
Air pollution is the third highest cause of death globally, killing more people than tobacco, with associated early deaths doubled from previous estimates (Lelieveld, 2019). In the UK alone, air pollution leads to 40,000 deaths per year and reduces lifespans by up to two years. In addition, recent scientific studies (Setti, 2020; Xiao, 2020) have indicated a strong correlation between higher air pollution levels and greater COVID-19 spread/transmission incidence. In the frontier economies, the disease burden has shifted from a profile dominated by infectious diseases to one increasingly characterised by non-communicable diseases (NCDs). Air pollution is now the leading environmental risk factor for NCDs resulting in millions of premature deaths and accelerating rates of chronic disease worldwide. The cost of poor air quality is not only paid for by our health – estimates suggest that air pollution improvements can save £2.2 trillion annually as global direct costs (WHO,2016) through improvements to people’s health, worker productivity and life expectancy growth.
Measuring Air Quality Impact – Personal Exposure
Traditional approaches to measuring air quality in cities (using fixed sensors in particular locations) have the benefits of reliability and producing a long, comparable time series of data. However, estimating personal exposure using traditional fixed sensors, can either over or under-estimate the true level of personal exposure to pollutants – as discussed in a recent paper by one of the authors. Fortunately, there are now alternatives available such as the use of GPS equipped portable air quality sensors. These enable researchers to classify time-activity-location patterns automatically and use algorithms including machine learning techniques of spatio-temporal clustering to address the data accuracy challenges associated with fixed sensors.
In short, by asking pedestrians to carry low cost, lightweight sensors, it is possible to understand their individual exposure to pollutants, during the journeys that they actually take. This approach can be complementary to the overall monitoring provided by fixed sensors (which capture changes over time and can help evaluate the impact of other factors, for example the weather conditions). In the Clean Air Street Initiative, DULT and CPC are partnering with Atmospheric Sensors Ltd and the Indian Institute of Science to compare personal exposure levels on Church Street during pedestrianisation to other days – we expect to see a big improvement!
The Benefits of Pedestrianisation
Reducing motor-vehicle traffic on our streets or pedestrianising them entirely can play an important role in reducing air pollution in cities. In addition to removing or reducing the pollution directly caused by vehicles, these initiatives will often result in:
- Increased active travel choices (cycling, running) with the associated health benefits – as well as reductions to greenhouse gas emissions.
- Improved footfall for businesses on the streets concerned. With pedestrians less likely to be in a hurry to pass through the area, browsing and casual shopping levels increase.
- More custom for restaurant owners who are able to offer out-door dining in a pleasant environment
In the UK, many places have been implementing ‘low traffic neighbourhoods’ (LTNs: areas with much reduced vehicle access) – increasingly so following the pandemic. One of the pioneers of this approach was Waltham Forest, and residents there experienced improved life expectancy due to improvements to air quality and more exercise.
These benefits are real and important – but how long it takes to realise the benefits, and the nature of other unintended consequences can vary depending on the way in which pedestrianisation is rolled out and phased.
Different Approaches to Pedestrianisation
There are a range of ways in which local authorities can approach reducing / removing traffic from their streets which we summarise below:
- ‘Shock wave’ – pedestrianisation of a large area / number of streets in one go (Milan, 2015)
- Local closure – closing a single street in one go (Vienna; Toronto, 2008)
- Slow local – closing a single street – but introducing the measure slowly (New York Times Square case study, 2007-2011; Wolverhampton, 1987-1991)
- Slow expansion – moving from a slow local closure to incorporate other streets (Paris, over 20year plan 2010-2025)
The general lesson to be learned here is that ‘slow and steady is best’. With sudden, complete closures, travellers struggle to adjust and in the short term, traffic tends to just re-route to adjacent streets, making congestion and pollution even worse in those areas.
With a more incremental approach, travellers have time to adjust, often using alternative modes of transport altogether (the LTN experience found an overall reduction in traffic).
The process we are seeing in Bangalore (with Church street first being paved in cobble stones, then pedestrianised at weekends for a limited period of time before potentially making this permanent / expanding to other streets) therefore is a good example of best practice.
Paris provides another interesting example of the process of pedestrianisation and traffic reduction. Up until recently the streets were the responsibility of the police and traffic levels and pollution were high – however the mayor Anne Hidalgo unveiled a series of initiatives to reduce congestion (started in 2017 but accelerating during the pandemic), incrementally shutting stretches of riverside roads to traffic and recently announced an intention to convert the Champs Elysees (a large road) into a ‘garden’. The success of these initiatives however is supported by the fact that they aren’t stand-alone – but part of a wider set of policy choices and interventions – for example introduction of bike sharing programmes, regulatory measures restricting vehicle usage and positive economic incentives to other travel choices
The international experience of pedestrianisation suggests that, if carefully managed and implemented alongside other interventions and policy measures, the impact on the overall exposure levels to pollution among a population will be positive – with the associated benefits in terms of health and life expectancy. On top of this, we see improved economic outcomes and the creation of more pleasurable public spaces. Everyone wins!
Image Credits: Directorate of Urban Land Transport (DULT) & Government of Karnataka
 https://www.sciencedirect.com/science/article/pii/S1462901117301570 – Slovic and Ribeiro, 2018