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.

 
 
 
 

Transport for London’s fare zones secretly go up to 15

Some of these stations are in zones 10 to 12. Ooooh. Image: TfL.

The British capital, as every true-blooded Londoner knows, is divided into six concentric zones, from zone 1 in the centre to zone 6 in the green belt-hugging outer suburbs.

These are officially fare zones, which Transport for London (TfL) uses to determine the cost of your tube or rail journey. Unofficially, though, they’ve sort of become more than that, and like postcodes double as a sort of status symbol, a marker of how London-y a district actually is.

If you’re the sort of Londoner who’s also interested in transport nerdery, or who has spent any time studying the tube map, you’ll probably know that there are three more zones on the fringes of the capital. These, numbered 7 to 9, are used to set and collect fares at non-London stations where the Oyster card still works. But they differ from the first six, in that they aren’t concentric rings, but random patches, reflecting not distance from London but pre-existing and faintly arbitrary fares. Thus it is that at some points (on the Overground to Cheshunt, say) trains leaving zone 6 will visit zone 7. But at others they jump to 8 (on the train to Dartford) or 9 (on TfL rail to Brentwood), or skip them altogether.

Anyway: it turns out that, although they’re keeping it fairly quiet, the zones don’t stop at 9 either. They go all the way up to 15.

So I learned this week from the hero who runs the South East Rail Group Twitter feed, when they (well, let’s be honest: he) tweeted me this:

The choice of numbers is quite odd in its way. Purfleet, a small Thames-side village in Essex, is not only barely a mile from the London border, it’s actually inside the M25. Yet it’s all the way out in the notional zone 10. What gives?

TfL’s Ticketing + Revenue Update is a surprisingly jazzy internal newsletter about, well, you can probably guess. The September/October 2018 edition, published on WhatDoTheyKnow.com following a freedom of information request, contains a helpful explanation of what’s going on. The expansion of the Oyster card system

“has seen [Pay As You Go fare] acceptance extended to Grays, Hertford East, Shenfield, Dartford and Swanley. These expansions have been identified by additional zones mainly for PAYG caping and charging purposes.

“Although these additional zones appear on our staff PAYG map, they are no generally advertised to customers, as there is the risk of potentially confusing users or leading them to think that these ones function in exactly the same way as Zones 1-6.”


Fair enough: maps should make life less, not more, confusing, so labelling Shenfield et al. as “special fares apply” rather than zone whatever makes some sense. But why don’t these outer zone fares work the same way as the proper London ones?

“One of the reasons that the fare structure becomes much more complicated when you travel to stations beyond the Zone 6 boundary is that the various Train Operating Companies (TOCs) are responsible for setting the fares to and from their stations outside London. This means that they do not have to follow the standard TfL zonal fares and can mean that stations that are notionally indicated as being in the same fare zone for capping purposes may actually have very different charges for journeys to/from London."

In other words, these fares have been designed to fit in with pre-existing TOC charges. Greater Anglia would get a bit miffed if TfL unilaterally decided that Shenfield was zone 8, thus costing the TOC a whole pile of revenue. So it gets a higher, largely notional fare zone to reflect fares. It’s a mess. No wonder TfL doesn't tell us about them.

These “ghost zones”, as the South East Rail Group terms them, will actually be extending yet further. Zone 15 is reserved for some of the western-most Elizabeth line stations out to Reading, when that finally joins the system. Although whether the residents of zone 12 will one day follow in the venerable London tradition of looking down on the residents of zones 13-15 remains to be seen.

Jonn Elledge was the founding editor of CityMetric. He is on Twitter as @jonnelledge and on Facebook as JonnElledgeWrites.