Our theoretical intersection is a 4-way with two all-12" heads using 169 watt bulbs per thru approach and one 3M left turn signal per approach. There are also eight hand/man pedestrian signals using 69 watt bulbs.
8 normal signal bulbs 169W - 1352 watts
4 3M signal bulbs 150W - 600 watts
8 ped signal bulbs 69W each - 552 watts
Total Wattage: 2,504
Cost to run annually at 8.7¢ per KwH: $1,908.35
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Now let's say the county decides to upgrade the intersection. They ditch the 3Ms and throw in standard all-arrow left turn signals with LED arrows and everything else sticks around with LED upgrades. After all that, the intersection's power usage looks like this:
8 normal signal heads with Dialight LED modules: 67 watts - 8.3 watts per module, average
4 arrow left turn signal heads with Dialight LED modules: 24 watts - 6 watts per module, universal)
77.6 watts - 8 ped signals with Dialight countdown modules (9.7 watts per module, average)
Total Wattage: 168.6
Cost to run annually at 8.7¢ per KwH: $128.49
To put that into perspective, for the power required to run one 169W bulb, you could power an entire LED intersection, not including the controller.
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