Street lighting quality may at the moment seem an unlikely issue for citizens to get worked up about, but for municipalities the negative impact poor street lighting can have on the quality of life in a community is becoming increasingly clear. Good lighting is known to reduce crime, cut road accidents and to increase the sense of safety experienced by citizens. It can also enhance the attractiveness of a city, drawing more visitors and even businesses to the area.

But while improved street lighting may help people to feel safe outdoors at night, it should not be intrusive either: ‘light trespass’ from lighting that’s close to homes can cause a nuisance to people trying to relax or sleep. And although sufficiently bright street lighting should increase road safety, it must be designed in a way that avoids too much glare suddenly hitting car windscreens, blinding drivers momentarily. Attractive, comfortable lighting for all its obvious benefits must at the same be energy efficient, keeping costs low and helping to reduce environmental effects.
 

Devil’s dilemma?

Meeting all these different needs is a challenge because different people in the community can have different, seemingly mutually exclusive, priorities. And as municipalities increasingly adopt LED lighting to reduce costs, they need to ensure it provides the right quality too. In short, it needs to be not just affordable and energy efficient but also comfortable in all circumstances.

And that’s a challenge, as different people have different, seemingly mutually exclusive, priorities when it comes to street lighting. In addition, there’s pressure on the municipality not to compromise on street lighting quality, environmental friendliness or budgetary control. But you can’t please everyone. Especially when, ideally, everybody wants to have it all: good quality LED lighting that’s nevertheless still both affordable and energy efficient. Which means providers of street lighting face an unsolvable dilemma, right? Actually… wrong.

There's a widespread belief that you have to choose between comfortable lighting that’s easy on peoples' eyes or efficient but less restful lighting that is affordable and delivers the desired fast payback. Comfortable lighting for example needs closely-spaced luminaires which minimize the amount of light in the horizontal plane, but the increase in light points pushes up costs. More efficient and wider light distribution tends to produce glary, ‘cold’ light that most people find unpleasant.

In short, using harsh, glary functional street lighting that saves on energy costs can undermine all the good work of investing heavily in rejuvenating a neighborhood’s infrastructure and upgrading its look-&-feel.

Old-school charm, new-age technology

Recent breakthroughs in LED technology have now consigned the devil’s dilemma to the past.

For example, Philips Lighting’s GentleBeam® optical system offers visual comfort vastly superior to a ‘naked’ LED board. GentleBeam consists of a cover with a uni-dimensional microtexture (microlinear prisms) that enhances visual comfort while being highly efficient. It results in only 5-10% less efficient distribution of light, against a conventional 20-30%. Moreover, unlike diffusing plates, GentleBeam leaves the optical distribution of the LEDs intact.