Switching traffic signals to LEDs down to wire

They burn brighter and longer and use less energy — all while saving Colorado Springs taxpayers $107,000 annually.

The city’s multiyear program to replace incandescent light bulbs in traffic signals with light-emitting diode (LED) bulbs will wrap up in January with the installation of the last several hundred bulbs.

Started in 2005, the program is switching out 30,000 traffic signal bulbs at the city’s 520 intersections.

Old-style bulbs last two years or less, while the city can count on LEDs burning for five to 10 years.

LEDs, though, cost a lot more than the $3 traditional bulbs — $35 apiece for yellow and red bulbs, and $45 for green bulbs, which contain more expensive gases to achieve the green hue.

That translates into an investment of about $1 million for 30,000 bulbs every five to 10 years, compared with $90,000 for traditional bulbs every two years.

LEDs, however, use 84 percent less power than incandescent bulbs, city traffic engineering analyst Angela Perry said, according to an inhouse city study.

That means the city saves money in the long run and can reassign employees.

“The folks we were using changing bulbs, we can reassign them to other tasks, other backlogs we’ve had,” said city traffic program supervisor Terry Marcum. “It allows us to refocus our efforts” in other areas.

Moreover, fewer bulb changes mean less traffic disruption to replace lights, he noted.

Also, Perry said the bulbs’ cost is bound to come down.

“Over the last 10 years, the price has dropped dramatically,” Marcum said. “Ten years ago, a green LED cost $500.”

Durability is measured in how often the city has to change lights. In 2005, as the LED program was launched, workers received 4,252 malfunction calls.

In 2006, calls fell to 2,759, and this year only about 2,000 will be logged, Marcum said.

In addition to time and money savings and endurance, LEDs provide a brighter light than traditional bulbs, considered a safety feature because drivers can see LEDs better and from a greater distance.

Marcum said LEDs more readily meet the Institute of Traffic Engineering standard for brightness.

While a traditional bulb will go out completely when it dies, if one LED diode fails, the others boost the light to keep it burning.

LEDs do die, but those that fail before their guaranteed five-year life are under warranty, he said.