Why light at night may be a menace

Petrol stations, supermarkets, local councils and homeowners who use bright lights to illuminate property at night have got it all wrong. Far from increasing people's sense of security, strong lights are unsafe and frightening, a scientist told the meeting.

Nancy Clanton, an engineer from Boulder, Colorado, who has studied the effects of night lighting levels, said the recent trend to use bright lights on petrol-station forecourts and car parks can blind people with glare and create dark shadows where muggers can hide.

Architects have assumed that people feel safer in brightly lit areas but often the lights are so intense that they dazzle visitors, making them feel less sure of themselves, especially when they leave to go back into a less well-lit area, Dr Clanton said.

Humans can see quite well at night without bright artificial light, she said. "That's why in full moon light we can see so well. There is a huge potential to use lower light levels."

Researchers who studied people's reactions to light levels in public places found that the brightest places were not always viewed as the safest.

"Lighting levels had little to do with whether you felt safe. What had everything to do with it was the glare. The more glare you have, the harder it is to see," she said.