Unlike conventional light bulbs that simply burn out at the end of their life span, light-emitting diodes (LED) simply loose brightness, and start producing a dull glow. This behavior has made figuring out when they need replacing very difficult, but a new approach now addresses this shortcoming.
The method could turn out to be especially useful for authorities managing traffic lights in major cities. Most of these instruments have long since been switched from conventional light bulbs to LED.
At this point, response crews usually change the LED when they receive a complaint from drivers or pedestrians. But this approach is very resource- and time-consuming, since dispatching an entire crew and a vehicle to replace a single diode is not very economically feasible.
Now, investigators from the Missouri University of Science and Technology
(MUST) say that they have a potential solution to this problem. The instrument was developed by assistant professor of engineering management and systems engineering, Dr. Suzanna Long.
What the team created is a laser-based instrument for measuring LED intensity. The tool is capable of conducting readings from the roadside at night, therefore eliminating the need to have technicians use a bucket truck to manually inspect all traffic lights periodically.
“The majority of agencies replace LED signals on a spot basis when they receive a complaint. The maintenance costs associated with sending a crew out to replace a single LED are very high,” Long says.
“Our methodology provides a more cost-effective mechanism for determining replacement and allows agencies to meet goals of being good stewards of public money,” she goes on to explain.
Another approach that traffic light managers use today is to replace all LED when their warranty expires (usually 6 years). However, not all diodes have a similar life span. This varies depending on location, weather, the frequency of use and so on.
Details of how the laser system works were published in a special issue of the Engineering Management Journal, dedicated to transportation management.