Local authorities all over the U.K. are starting to dim streetlights to save money and reduce carbon emissions. Networked lamps and LED bulbs save energy and allow lights to be dimmed or switched off for part of the night. Yet residents are complaining that these cuts make them feel vulnerable, and motorist groups say that cutting lights means more road accidents.
Britain’s Automobile Association (AA) claims that six people have been killed thanks to the switch off by Warwickshire County Council, where lights on roads with 40-mph-and-above speed limits have been permanently cut:
Six deaths partly caused by councils switching off street lights to save money have left drivers no option but to drive on full beam along faster (40 mph) residential roads.
At least five pedestrians and a cyclist have been killed since 2009 because, according to accident investigators at inquests, drivers had little or no chance of avoiding the collisions on blacked-out roads with speed limits of 40 mph or higher.
New research, based on police data across England and Wales, however, has found the opposite. The study from the University College London sought to see if there really was any harm from street light dimming.
There was no evidence that any street lighting adaptation strategy was associated with a change in collisions at night
This study found little evidence of harmful effects of switch off, part-night lighting, dimming, or changes to white light/LEDs on road collisions or crime in England and Wales.
The study does point out that both crime and accident figures may have stayed the same because people were scared of the dark and remained indoors. But AA’s chosen accidents seem to break rather than bolster its case. It seems that if the motorists who killed the pedestrians had been running their headlamps at full-beam, they would have seen their victims in time.
The aversion to dimming or switching off the lights is a subjective one. People feel safer on well-lit streets, even though light levels make little difference to their actual security. Police like blanket white lighting because their surveillance cameras work better. But even if safety isn’t affected by fewer lights, the social impact is there. Street lighting might be viewed in the same light (pun intended) as benches or other street infrastructure. People may be less likely to use public spaces at night, or during dark winter afternoons and evenings, if there is no lighting.
But all-night light might be harming us. Research has shown that electric lighting at night can increase the risk of breast cancer, and we’ve seen that blue light, like that in our tablets and phones, as well as modern LED bulbs, interrupts our circadian rhythms and stops us from sleeping.
The AMA even recognizes that “exposure to excessive light at night, including extended use of various electronic media, can disrupt sleep or exacerbate sleep disorders, especially in children and adolescents.” It also recommends “developing and implementing technologies to reduce glare from vehicle headlamps and roadway lighting schemes.”
Speaking as someone who has streetlight right outside his bedroom window, I can get behind this recommendation. But our animal friends have it even worse. Moths and other nocturnal insects are confused by street lighting, and evidence from New Zealand says that white LED lights are even worse, attracting 48% more insects than regular old high-pressure sodium-vapor lamps.
Dark sky advocates, who think that we should be able to see the heavens even from a city center, are also happy in dimmer lighting. In the end, cutting out lights, or at least cutting back on lighting after midnight, could be very good for us.