Public lighting, LEDs and safety: it's complicated
Bright lighting might be one of the first things that comes to mind when thinking about security in public places, but scratch the surface and you’ll find a much more complex picture.
Recent analysis of data from the UK has examined street lighting in relation to crime and made the surprising discovery that switching lights off at midnight, as is common in England and parts of Europe, might be linked to a reduction in certain types of crime.1
As part of this research project, academics from the UK, Singapore and New Zealand examined street lighting data from the (UK) Thames Valley Policing area between April 2004 and September 2013. They compared these figures to crime data from Thames Valley Police over the same 10-year period, covering offences of residential burglary, robbery, vehicle crime and violence, since these were the offences that would be most expected to be affected by changes to street lighting. Their findings were published in the Journal of Quantitative Criminology.
The lighting data accounted for all lighting changes implemented by the councils involved, including switching off lights between midnight and 6 am (‘part-night’ lighting or PNL), dimming (where lights remained on all night, but their illumination was reduced) and the replacement of orange sodium lamps with white lights.
For streets where part-night lighting was in place, the researchers made a startling discovery: in these semi-dark streets, there was a strong association with a reduction in total night-time crime and especially theft from vehicles. In contrast, dimmed light had no significant impact.
For street segments adjacent to streets with part-night lighting, the findings suggested that there was an increase in overall night-time crime of about 18%, mainly driven by increases in theft from vehicles. Interestingly, there was some evidence of a decrease in overall crime on streets adjacent to white light interventions, which appeared to be driven by decreases in violent crimes on these streets.
How lighting interventions affected crime 24/7
When the analysis was widened out to include the impact of lighting changes on crime occurring in the day as well as at night, it showed part-night lighting was strongly associated with a reduction in total crime and burglary along the streets where it was implemented. There was also evidence of an association between PNL and a reduction in violent crime. There was some evidence that dimming was associated with a reduction in robbery, while white light was associated with a decrease in all crime, driven by decreases in burglaries.
For adjacent streets, there was strong evidence of an association between PNL and reductions in total crime and violent crime. There was no evidence of associations between dimming nor white light and crime on adjacent streets.
When looking at the total impact of street lighting interventions (ie, the total net effect with both the intervention and adjacent streets combined), part-night lighting comes out on top in terms of crime reduction. PNL streets were associated with a reduction in total crime, burglary, theft from vehicles and violence. Dimming was only found to be associated with a net increase of theft from vehicles and white light was only associated with net reductions in burglary.
But while PNL was associated with a reduction in theft from vehicles on the streets where it was implemented, there was also evidence of a similar increase in theft from vehicles on adjacent streets, suggesting there was spatial displacement of these crimes to better-lit streets nearby.
Possible explanations
In explaining their findings about PNL, the researchers referred to “rational choice theory”, in which offenders engage in a cost-benefit analysis. Put simply, darkness makes it much harder for would-be car thieves to see what they’re dealing with — how secure a vehicle is, for example, or whether it contains valuable goods — and to see what they’re doing, for instance when removing items like hub caps. If they introduce an artificial light like a torch, this is likely to attract unwanted attention. So all in all, the costs would seem to outweigh the benefits in this scenario. This also explains the displacement of such crimes to adjacent streets without PNL.
The study’s conclusion pointed out the complicated relationship between public lighting, security and crime: “The findings of this study suggest that the mechanism by which street lighting has been proposed to reduce crime — increased visibility at night — may be one that can also increase vehicle crime. This speaks to the inherent specificity in the opportunity structure of different crimes; environmental features make some types of crime more likely whilst simultaneously making other types of crime less likely.”
Importance of community perceptions
In addition to more straightforward explanations for the effectiveness of public lighting, for example, deterring crime through making offenders more visible, much of the research into public lighting and security relates to community perceptions. In the ‘community cohesion’ model cited in the Thames Valley study, an improvement in lighting infrastructure carried out by a council might have the effect of making the community feel invested in and valued, which in turn increases “community pride, cohesion and informal social control” — leading to safer streets.2
But introducing bright LEDs to no-go areas won’t necessarily create a perception of security.
In a background report3 on public safety based on data gathered in its Annual Customer Satisfaction Survey 2019, the City of Yarra noted that “very bright and over-lit spaces do not necessarily correlate with observations of safety and can, in fact, increase perceptions that a site is unsafe.4 By flooding a space with light, there can be a sharp drop-off of light beyond paths. This contrast can be disorientating and can make people feel less safe5.”
The City of Yarra’s report emphasised the importance of being site-specific when it comes to security lighting, and noted that this sort of approach is hampered by the Australian Standard for public lighting, in which illuminance (the measure of light falling on a surface, or lux level) is the only unit of measurement required for compliance.
“The effect of utilising such a singular approach to inform what is considered acceptable under the ‘Australian Standard’ is that it limits buy-in to consider a more holistic approach to lighting design such as through a combination of lighting designs and techniques, to achieve a more responsive outcome in localised contexts.”6
Pros and cons of white light
The uptake of LED streetlights in Australia over the past seven years has been exponential. According to a recent IPWEA article, ‘A Stocktake of Australia’s Progress Towards Smart Street Lighting’, about 1.4 million of the 2.5 million streetlights in Australia have been converted to LEDs, totalling some 57% of the national portfolio of street lighting. This is up from about 6.5% of Australia’s 2.3 million streetlights in 2016, when the IPWEA first started its Street Lighting & Smart Controls Program.7
The LED ramp-up shows no sign of slowing down. Ausgrid has installed 170,000 LEDs in 30 council areas since its LED streetlight rollout began in November 2018, with the program expected to be completed by the end of the 2025 financial year.8 As part of the Western Sydney Energy Program, Endeavour Energy will replace mercury vapour lamps with LED streetlights across seven Western Sydney councils, with more than 52,000 fittings to be installed; completion is expected by 2024.9
The shift to LEDs in Australia brings with it undeniable environmental and economic benefits, as well as possible improvements in road safety (white-coloured streetlights have been associated with faster driver reaction times when compared to yellow sodium lights).10 On the flipside, concerns have been raised about potential health and security issues, including interfering with the sleep cycles of animals and humans11, and increasing property crime. (Though as we’ve seen, the latter issue is a complex one!)
Though criticised by Yarra City Council, Australia’s public lighting standard (AS/NZS 1158) might ameliorate these concerns somewhat, as, according to Next Energy Lighting Director Graham Mawer, writing for the IPWEA, it “is unique in permitting extremely low lighting levels and long spacings between lights on residential roads”. Mawer went on to say that “as society has become more attuned to the environmental impact of public lighting, Australia’s comparatively lower lighting levels are coming to be viewed as a benefit in some quarters”.12 However, this uniquely dim street lighting is not helpful should residential streetlights need to be temporarily brightened, for example, in the event of a road traffic accident; this is where smart lighting could help.
A smarter approach
While Australia’s LED street lighting transition has been enthusiastic, the country has been slow to adopt smart lighting controls, which would enable automated dimming and shutting-off of streetlights — as well as brightening.
If there’s one takeaway from the existing research on public lighting and security, it’s that there’s no single solution to this multifaceted problem. Effective security lighting must take into account location, community and the type of crime that’s occurring in a particular area; and be considered in tandem with other security measures, like cameras. Increasing the number of smart street lighting controls in Australia would enhance the responsiveness of public lighting — surely a useful measure when it comes to tackling the nuances of security infrastructure.
1, 2. Tompson, L., Steinbach, R., Johnson, S.D. et al. Absence of Street Lighting May Prevent Vehicle Crime, but Spatial and Temporal Displacement Remains a Concern. J Quant Criminol (2022). https://doi.org/10.1007/s10940-022-09539-8
4. https://www.arup.com/projects/perceptions-of-night-time-safety-women-and-girls
5. https://www.plan.org.au/freetobe
6. p.5, City of Yarra background report, 2020
7. https://insite.ipwea.org/a-stocktake-of-australias-progress-towards-smart-street-lighting/
8. https://www.ausgrid.com.au/In-your-community/Streetlights/LED-Streetlight-Rollout
10, 11. Blue Light — Should We Be Giving It the Green or Red Light? https://www.youtube.com/watch?v=U7QHzEypAkc&list=PLeiUxx3SrYWa-zz7ugSpwV4PmILr8tojh&index=2
12. https://insite.ipwea.org/australias-street-lighting-transition/
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