Traffic light change to save thousands of dollars

Wednesday, November 21, 2001

Cape Girardeau's traffic lights are about to change.

The city plans to install longer-lasting, low-power bulbs in its traffic signals that they say will shine brighter and save thousands of dollars in energy costs each year.

They also intend to install pedestrian push buttons at intersections that will let electromagnetic sensors that detect cars also know that pedestrians are waiting to cross.

The new bulbs are called light-emitting diodes, or LED bulbs, and will cost the city about $83,000 to upgrade 591 traffic signal bulbs, public works director Doug Leslie said.

LED signals produce brighter colored light because they don't need to be filtered.

"They're actually significantly brighter," Leslie said. "Probably all the drivers will notice."

The upgrade consists of replacing the 135-watt incandescent bulbs with 14-watt LED bulbs at all 13 intersections maintained by the city. That doesn't include state-maintained roads like Kingshighway and Shawnee Parkway, Leslie said.

Because of the greatly reduced wattage, LED bulbs save 80 to 90 percent of the energy consumed by incandescent traffic signals and last five to 10 times longer, Leslie said.

Each 12-inch unit is made up of about two dozen bulbs and will cost about $140 per unit. The bulbs used now are about $7 each.

Leslie said the savings will come in long-term energy costs. Current energy costs for the 135-watt bulbs are $14,840 a year. The estimated energy costs for the 14-watt LED bulbs are $1,540 a year, a savings of $13,300 a year, Leslie said.

Leslie also said the city will save another $2,000 per year in manpower from changing the bulbs less often.

The new bulbs will be installed in phases, likely beginning in March and ending in September. "We'll probably do an intersection at a time," Leslie said.

The city will buy the bulbs with a loan through the Missouri Department of Natural Resources. Leslie said the savings will repay the loan. After the loan is repaid, the city will have a permanent benefit from continued lower energy and maintenance costs, he said.

Assistant public works director Tim Gramling said the city is on a faster track to put in the pedestrian push buttons at each city-maintained intersection. He said the words on the pedestrian signals -- walk and don't walk -- will be replaced with symbols of a walker and a hand indicating don't walk. LED bulbs will be used in pedestrian signals too, he said.

smoyers@semissourian.com

335-6611, extension 137

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