MnDOT replaces roadside lights with LED lamps

The Minnesota Department of Transportation is replacing tens of thousands of roadside lights across Minnesota, for what it hopes will be big savings.

MnDOT says it's replacing more than 28,000 lights along highways, under bridges and other locations. Out are high-pressure sodium lamps, some that draw more than 400 watts of energy. In are LED fixtures that may last up to 18 years.

"As far as the light level on the road, you should be seeing the same amount of light on the road, but it's going to be a white light, instead of that orange-ish light," says Sue Zarling, MnDOT traffic electrical systems engineer.

Switching to LEDs results in about 65 percent in energy savings, according to a MnDOT spokesperson. That adds up to $2 million saved annually.

MnDOT officials say they're also hoping to end a four-year replacement program on Twin Cities highways that costs more than $400 thousand a year and has crews working amid traffic to relamp the lights. Engineers think the new lights will pay for themselves in about six years.

The Twin Cities area has about 18,000 MnDOT lights, and the change is expected to be finished by September and run about $11 million. Outstate Minnesota will take until 2020 to completely change over, because the sparsity of the lights.

Zarling says some lights aren't practical to convert yet: The lights in the Lowry tunnel, for instance, will likely stay for now because the cost of replacing them is prohibitive. Poles more than 100 feet high at some interstate interchanges also don't have LED equivalent replacements yet.