Streetlights are changing

Just a memory

I remember in my childhood being fascinated by the weird colours my clothes would appear under sodium vapour streetlights. Orange coloured sodium vapour lamps have dominated main roads for decades because they are efficient and practical. Their colour rendering is terrible, but all they need to do is light the road. We’ve become accustomed to their strange glow and barely notice them. It’s only in the last few years that the price and energy efficiency of LEDs have been able to match them and in cities across the world they are steadily being replaced. In not too many years they will be just a memory.

Clear advantages

The change to white light LED has not been universally welcomed even though the advantages seem clear. LEDs provide better illumination. Motorists can see more and people feel safer. LEDs are longer lived and need less maintenance. They save energy and money.

Downsides

There is an element of nostalgia in objections to the change of light, but there are also some real downsides that have to be considered. Some of the first LED streetlights were too much of a contrast to the old lights with high colour temperatures appearing to be too cold and intrusive. Higher colour temperatures and light with too much blue don’t suit the nocturnal landscape and aren’t very popular. Light that has a lot of blue in the spectrum suppresses the production of melatonin, the hormone that is linked with going to sleep. Whiter light is said to attract more insects and have more potential to disturb ecosystems more than sodium vapour. Red LED streetlights have been used for some time in areas where marine turtles nest because the hatchlings become confused by white light and move inland toward it instead of out to sea. Star gazers worry that light pollution will make the night sky too bright.

Irresistible change

All these problems can be addressed with good design and consultation. The issues outlined are unintended consequences of the rush to convert to a technology that offers compelling savings. And the savings are so compelling that the conversion of streetlights to LED is irresistible. It doesn’t matter how fond you may have become of the “moody urban glow” of sodium vapour, you are going to have to get used to your clothes looking the same everywhere.