LEDs improve road safety

17 Jun 2002

Intelligent, solar-powered, LED studs could decrease the number of road accidents.

The number of motoring accidents occurring in bad weather conditions or on notorious sections of road looks set to fall thanks to an intelligent road stud developed by UK-based company Astucia.

Using high-brightness LEDs, light projected from each stud can be seen at up to 900 m away during night-time darkness.

The intelligent studs also have the ability to warn drivers when they are too close to the car in front in foggy conditions.

The company's core product is a stud called the SolarLight Night (SLN). Unlike conventional retro-reflecting road studs, the SLN system does not rely on headlights to delineate the road. Sensors within the stud monitor the ambient light levels and automatically activate the LEDs when daylight levels drop below preset levels.

In the basic model, the SLN contains one color of LED according to regional requirements. Company director Ilyas Sharif explained: "In the UK, this would be a white LED for the center road markings, red for the left hand side and amber for the right hand side."

Within the umbrella of the SLN range, advanced models offer greater functionality. "In foggy conditions, a white LED activates when light levels are low. When headlights hit the stud, the LED shines amber. If a second car following the first is too close, the amber LED turns red to warn the driver of the second car," said Sharif. "This is called SolarLight trail and tailgate functionality," he added.

The Asturia stud employs integral solar panels that capture sunlight and the car's headlamps. This charges a nickel hydride battery that in turn powers the LEDs giving an output of up to 18 cd.

The LEDs pulse with a frequency of 54 Hz to reduce power consumption although this can be altered. "You may want to decrease the rate to 2 Hz to warn drivers of a particularly tight bend. Different flash rates are available," said Sharif.

With installations all over the world, Sharif says that the devices have now passed their initial test phase. "We are now targeting the SLN towards replacing the traditional studs in sections of road that are known to be high-risk accident areas," he said.

The basic SLN model costs USD 32.

Author
Jacqueline Hewett is news reporter on Optics.org and Opto & Laser Europe magazine.