The Minnesota Department of Transportation (MnDOT) is undertaking a statewide lighting conversion project and saving money while improving safety.
The project involves converting more than 28,500 roadway lights from traditional high-pressure sodium to LED or light emitting diode technology. The conversion includes replacing the light fixtures and bulbs.
"Drivers will see whiter light, but the biggest impacts will be a large reduction in the energy bill and eliminating the cost of bulb replacement every four years," said Michael Gerbensky, signal design and lighting management engineer for MnDOT's Twin Cities' Metro area.
MnDOT said it expects the LEDs will last about 100,000 hours, or an average of 18 years.
"This means having our maintenance personnel out on the roadway less often, which reduces traffic control costs and it means improved safety," Gerbensky said. "That savings can go to preserving our roadways."
MnDOT said it expects the average annual savings in energy costs will be up to $1.45 million, plus another $500,000 savings a year in maintenance and replacement costs for light fixtures and bulbs.
It is mainly installing the new lights on bridges and roadways, but also said it is considering LEDs in such areas as weigh stations, rest areas, tunnels and maintenance facilities.
It will install most of the new lights in the in the Twin Cities Metro area, but said about 10,000 lights will be elsewhere In Minnesota.
Installations in the Twin Cities will be completed by the end of this year, MnDOT said, while the conversions elsewhere will take longer because of the large geographical area crews need to cover. However, it expects to complete the entire conversion by 2020, said Sue Zarling, traffic electrical systems engineer.