What makes people feel safe at night? On the science of street lights

Street lights in Kabul, shortly after they were installed for the first time in 2003. Image: Getty.

Winter is coming: the nights are drawing in and in the Northern Hemisphere the hours of darkness already outnumber the hours of daylight. Research has shown that darkness produces a big fall in the number of people out walking – and a major reason for this is that people feel less safe walking in the dark.

There may be an evolutionary explanation for why people feel less safe at night – we can’t see as well, and this may have exposed our ancestors to greater threat from predators. Nowadays, it’s not so much the prospect of being eaten by a savage beast that concerns would-be pedestrians, but the fear of being mugged or victimised.

Some studies suggest that new outdoor lighting can reduce crime rates in an area, but there is conflicting evidence on this. A large review of research found a link between new lighting and reduced crime rates, but improvements were seen in daylight as well as darkness, suggesting that street lighting is not the only factor. This review has also been criticised by other researchers, and a large statistical analysis found no link between crime rates and switching off or dimming street lighting at night.

Street lights may or may not have an effect on crime, but one thing’s for sure – brighter levels of light do make people feel safer when walking at night. This can lead to a significant increase in the number of minutes people spend walking each week. It can also reduce the number of people who avoid leaving their homes at night, reduce social isolation, improve physical and mental well-being and increase community pride.

Street lighting can improve the quality of neighbourhood life by making people feel safer – but, even so, it would be unwise to flood our streets with light at night. Street lighting costs money: the UK’s annual bill is estimated at around £220m. Artificial light at night may also have a negative impact on wildlife and the natural world, for example by stunting the growth of frogs and toads and preventing them from laying their eggs.

The skyglow from street lights also means we rarely get to see the true wonder of the night sky, frustrating astronomers and limiting our appreciation of the natural environment. For these reasons, lighting should be used selectively and efficiently – and this requires good guidance to help those responsible for installing and maintaining our street lighting.

The guidelines for street lighting in the UK and many other countries are currently based on questionable evidence. That’s why our lighting research group at the University of Sheffield undertook a programme of research to find out how lighting relates to feelings of reassurance after dark, and improve the evidence on which lighting guidelines are based.


Illuminating evidence

In one recent experiment, we asked people to walk along a number of streets in the city of Sheffield at night and rate how safe they felt. We also asked these people to walk and rate the streets in the day, to create a baseline measure of safety and to account for biases that may occur if safety ratings were taken only after dark.

The difference in safety ratings between the day and night walks told us something about the lighting on that street – the smaller the difference between day and dark ratings, the safer people felt due to the lighting. We compared our participants’ different ratings against measures of the lighting on each street, including the average illuminance (amount of light falling on the street surface) and uniformity (how evenly spread out the lighting was).

Today, average illuminance is the main measure used when installing and evaluating street lighting. But we found that, while increasing average illuminance was linked with improved feelings of safety, uniformity was more important for making people feel safe. So it might be more important to have evenly distributed lighting, rather than bright lighting, to make people feel safer.

Local authorities are undergoing major changes to their lighting, as they replace the traditional orange sodium lamps with new LED lighting. These new LEDs are more energy efficient, which saves taxpayers’ money. They also give councils greater control over the lighting they provide, for example by dimming and switching off when there are no pedestrians about.

Used properly, street lights can improve people’s lives and help neighbourhoods come alive at night. But there’s still a lot to discover about how people respond to street lighting and the impacts it has on society and the environment – experiments such as these can help to light the way.

The Conversation

Jim Uttley, Research Fellow, University of Leeds; Aleksandra Liachenko Monteiro, PhD Candidate, University of Sheffield, and Steve Fotios, Professor of Lighting and Visual Perception, University of Sheffield.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

 
 
 
 

How can cities protect common green space for the future?

Newcastle Town Moor. Image: Chabe01/Wikimedia Commons.

Urban green space comes in a variety of forms – parks, allotments, gardens, ‘strays’ to mention just a few. One of the most iconic is the urban “common” – these are often extensive tracts of green space in or adjacent to large urban areas that provide publicly accountable, open, green, spaces vital for culture, health, wellbeing and biodiversity in the metropolitan context. Examples include Epping Forest and Wimbledon common in London, Town Moor in Newcastle, Mousehold Heath in Norwich, or Clifton Downs in Bristol.

The term “common” creates in the public consciousness notions of communal ownership, control and use. In fact, this is often a misconception. Most urban “commons” are not community-owned assets, and many have different legal identities, and differing degrees of legal protection and security. These are often the result of a history of different political, social and economic forces shaping land use in each metropolitan context. Epping Forest and Town Moor in Newcastle are, for example, protected by Acts of Parliament. Clifton Down in Bristol is a “traditional” common registered under the Commons Registration Act 1965, which guarantees its status as common land.

Other areas commonly regarded by the public as commons are in actual fact simply urban green space that is preserved by some lesser legal protection - for example, through the planning system, which may designate them as green space or as conservation areas within the local development plan. But plans can change, and much green space is lost to development annually.

Indeed, in the age of austerity, local authorities have been driven to sell much green space that they themselves own to raise funds to provide front line local services, like schools and social care. In this context, true urban commons – those that have the legal status of common land – are extremely precious community assets, in that they are protected from development and preserved for future generations.

But do we value them highly enough? Do we appreciate their importance in shaping our community’s consciousness of its own identity and history? Do we use them to the full as recreational open spaces and if not, how can we champion our urban commons and develop new ways to engage the urban public more fully in their use, management and stewardship?   


A new interdisciplinary 3-year project (“Wastes and Strays”) involving academics from Newcastle University, Exeter University, Sheffield University and Brighton University will address many of these issues. The project will explore the complex social and political history of the urban common, as well as their legal and cultural status today, and in doing so devise tools and methods of negotiation, inclusivity and creativity to inform their future.

The project will make in-depth studies of four iconic urban commons: Town Moor, Newcastle; Valley Gardens, Brighton; Mousehold Heath, Norwich; and Clifton Down, Bristol. It will look at the multiple, negotiated historic uses and legal origins of the common in each case, and its contemporary meaning, popular perception, biodiversity and public use.

One strand of the research is closely focussed to encouraging the more extensive use of urban commons as vital green space for recreation and other community uses, important for mental and physical wellbeing. It will be looking to develop new strategies for community engagement with the urban commons as community assets and will work in partnership with local communities and relevant stakeholder groups to generate ideas for the future of urban commons, in the spirit of their negotiated pasts.

The big idea is to generate a multifaceted definition of the urban common to provide a robust base for education initiatives and future public policy guidance, informing their development and use as a diverse cultural and ecological space.

For hundreds of years, these unique, open spaces have played a varied, but important, role in the individual stories of our towns and cities. We need to develop new and imaginative ways to use them and foster a greater sense of community involvement if we are to preserve them for future generations.

Chris Rodgers is a professor of Law at Newcastle University.