Title: The Low Traffic Neighbourhoods in London: a mixed-methods study of benefits, harms, and experiences
Funder: Department of Health and Social Care

Abstract: In recent years, levels of motor traffic have started increasing after a period of decline. This is worrying for many reasons. Every year in the UK two thousand people die in road crashes, with tens of thousands seriously injured. Tens of thousands more die early each year because of air pollution, much of which comes from motor vehicles. If people walk or cycle more, and drive less, they are also much more likely to get the exercise they need to stay healthy._x000D_ _x000D_ The way we travel is not just a matter of personal choice. Our streets are often busy with cars, even smaller side streets. Streets are difficult to cross on foot, particularly for older people. They are scary to cycle on, particularly for children. This can mean that the easiest and most comfortable way to travel is by car. For these reasons, local authorities have been implementing schemes that restrict motor traffic and make more space for walking or cycling._x000D_ _x000D_ ‘Low Traffic Neighbourhoods’ (LTNs) are a type of traffic scheme that stop people in motor vehicles cutting through side streets. The aim is to make walking and cycling safer and more comfortable (as there are fewer cars), and make driving less convenient, encouraging people to walk or cycle instead. Around 90% of people in cities live on side streets, so if these schemes are found to work, many more could be built. LTNs are novel in the UK but are being rolled out fast - already 4% of Londoners live in an LTN built Mar-Sep 2020._x000D_ _x000D_ LTNs have the potential to bring large benefits but also harms. We need to know whether the goals – to increase walking and cycling and reduce road injury risk – are being met. We also need to know about any negative impacts, e.g. for residents on surrounding boundary roads where there might be increased congestion, or for those disabled people who need a car to get around. Finally, because LTNs are often controversial, we are keen to hear the voices of the people directly affected._x000D_ _x000D_ Our project will examine positive and negative impacts of 7 new LTNs that will shortly be built in London. We are already collecting baseline quantitative data on volumes of walking and cycling; walking and cycling diversity; congestion on the boundary roads; and local car journey times. We will keep collecting this data for three years of follow-up, providing evidence on both short- and long-term impacts. Changes in these 7 new LTNs will be compared to changes in 7 matched control areas, to take account of background changes in travel patterns as we move out of the Covid-19 pandemic. Based on these data, we will model health impacts in terms of changes in physical activity, road traffic injuries, and air pollution._x000D_ _x000D_ As well as measuring effects of LTNs, we want to study how people experience them. We will speak to 80 residents in depth about how the scheme affects their lives, one and two years after schemes go in, ensuring a diverse mix of participants. We will conduct focus groups with local disabled people about their experiences of these LTNs, and organise community events to gather further information about how people experience their local streets. We will interview local authority officers to find out how implementation worked and if improvements could be made._x000D_ _x000D_ This project is uniquely placed to generate robust and timely evidence that can inform the future of LTN-type interventions. Our findings will be of wide interest to people and organisations in London, the UK, and abroad.

Lay abstract: RESEARCH QUESTIONS: Do new Low Traffic Neighbourhoods (LTNs) lead to more, and more diverse, walking and cycling (active travel), compared to control areas? What are the health benefits from these and other changes (e.g. reduced road injury risk)? Do these schemes cause harms, including congestion on boundary roads or longer journeys for disabled people without alternatives to cars? What factors have affected how local people have experienced and responded to LTNs, and how can policymakers navigate controversy surrounding these schemes, and make them more inclusive?_x000D_ _x000D_ BACKGROUND: LTNs are transport interventions that substantially reduce motor traffic in a contiguous set of residential streets. They can involve street furniture such as planters or camera-enforced closures. From a low baseline, LTNs were implemented rapidly in 2020, as part of the UK’s Covid-19 response. London built them fastest and 4% of its population (300,000 people) live in areas covered by the 72 LTNs introduced between March to September 2020. However, monitoring of LTN impacts has been patchy, often lacking ‘before’ data and control sites – a key limitation given dramatic ongoing changes in travel behaviour._x000D_ _x000D_ AIM: To examine the benefits and harms of new LTN schemes, experiences of those living in or near LTNs, and how policymakers can navigate controversy. Our study focus will be 7 new London LTNs due to be implemented Autumn 2021 – Spring 2022, plus 7 matched control areas. These have a resident population of 115,548 (61,492 in LTNs, 54,056 in control areas)._x000D_ _x000D_ OBJECTIVES: _x000D_ 1. To collect quantitative follow-up data in LTNs and control areas for three years following the start of baseline data collection. This will cover walking and cycling volumes, walking and cycling diversity, congestion on boundary roads, and local car journey times. Baseline data collection is successfully underway, with ‘before’ data available from June for five schemes and from August/September for a further two. _x000D_ 2. To model health and health economic impacts._x000D_ 3. To collect qualitative data about experiences of local residents, including disabled people, and of policymakers._x000D_ 4. To ensure that the future of LTN-type interventions is informed by a rigorous mixed-methods evaluation. _x000D_ _x000D_ METHODS:_x000D_ A. Quantitative: controlled before-and-after analysis to examine both potential harms and benefits. This will include the use of controlled interrupted time series analyses for continuously-collected data. _x000D_ B. Health economic impact assessment, incorporating LTN impacts on physical activity, injuries, and air pollution._x000D_ C. Qualitative: interviews, focus groups, and 'action research' with people living in or near the intervention, with a specific focus on disabled people; and with stakeholders implementing schemes. Longitudinal component to explore how experiences change as LTNs 'bed in'._x000D_ _x000D_ ANTICIPATED IMPACT AND DISSEMINATION: LTNs are ambitious, scalable, novel, and controversial. UK cities are quickly rolling them out. The evidence base has not kept up, and key decisions are currently often made without data. This project is uniquely placed to provide policymakers with robust and timely evidence. We will publish interim quantitative findings early (from late 2022) followed by analysis of longer-term changes, and qualitative findings, throughout our 3-year follow-up data collection. We have an outstanding track record of disseminating our findings widely and influencing policy.

Research activity codes: 3.2 INTERVENTIONS TO ALTER PHYSICAL AND BIOLOGICAL ENVIRONMENTAL RISKS
Health categories: GENERIC HEALTH RELEVANCE