Founded over 200 years ago along the Mississippi River in Missouri, the city of Cape Girardeau is now home to almost 38,000 residents. The Missouri Highway 74 corridor through the city's downtown is one of the busiest thoroughfares in the city, leading up to the Emerson Memorial Bridge across the Mississippi and connecting Cape Girardeau with Illinois. Along this stretch of road, as well as North Kings highway, 250-W high-pressure sodium (HPS) street lights kept maintenance crews busy with frequent bulb changes.

The 120-W StreetSense™ LED street lights have a lifetime of at least 15 years.
“Each is equipped with a photocell, which means we’d have to send a crew out to scout for burn-outs each night, an overtime expense that we’d prefer to avoid,” said Geoff Dial, Special Projects Coordinator in the Public Works Department in the city. “The ballasts were getting to be around five to seven years old, and lately it seemed as though the lights were going out more frequently than ever before. Almost every day we had one burn out, despite our efforts to keep up with the changes.”

As part of an overall plan to achieve more sustainable operations, officials in Cape Girardeau secured a $190,000 grant to make energy-efficiency improvements to city-owned facilities. Part of the funding, which was received through the Department of Energy’s Energy Efficiency & Conservation Block Grant (EECBG), was designated to replace over a hundred of the streetlights with new high-efficiency light-emitting diode (LED) street lights that would save the city money and free up resources to attend to other, more pressing matters besides changing light bulbs.

New LED street lights illuminate the Missouri Highway 74 through Cape Girardeau.
Having already replaced traffic signals in 21 intersections and rail signals in one railroad crossing with Dialight’s LED signals, the city looked to the company once again meet its needs. The EECBG grant mandated that all equipment purchased must comply with the Buy Amer ican requirement of the American Recovery & Re invest ment Act. Dialight’s Street Sense LED street lights fixtures met Cape Girardeau’s technological and performance needs, and are made at the company's Roxboro, NC manufacturing facility — satisfying the Buy American requirement.

Working with Brown Traffic, a Dialight distributor in Davenport, IA, the city has now replaced 104 of its 250-W HPS lights with the much more efficient 120-W Dialight LED units along Highway 74 and North Kings highway. The first 104 units installed represent about onefourth of the street lighting under the city’s charge.

With an output of 9,000 lumens (73 lm/W) and a color rend ering index (CRI) of 72 with 6000K cool white light, the new StreetSense LED lights provide illumination with a light that is easier on the eyes for motorists. The units are driven at 350 mA for extended life and built-in thermal overload protection circuitry provides long-term reliability.

“Because I know these new lights will last for at least 15 years, I’m looking forward to not having to touch these LED fixtures for a long time,” said Dial.

Dial also estimates that the new LED units will cut the city’s energy consumption by nearly 70,000 kWh, from about 160,000 kWh to 89,000 kWh, which will help offset future increases in energy costs.


Lighting Technology Magazine

This article first appeared in the November, 2011 issue of Lighting Technology Magazine.

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