The overhead signs along Arizona highways each save the Arizona Department of Transportation (ADOT) approximately $1,000 annually since employees came up with replacing halogen with LED lighting.

Workers conceived of a way to replace obsolete halogen bulbs with LED-powered illumination for roadway advisories conveying travel updates to motorists in the form of a retrofit kit, according to a news release. The change decreases energy waste and improves driver safety with stronger lights.

“The LED system is a brighter, clearer light, so it’s easier to see the signs and read the messages,” Chuck Hill, ADOT traffic signals and lighting supervisor, said in the release.

The retrofit saved the department money; while a total replacement would have cost $300,000, workers swapped out parts for approximately $42,000 per sign, the release said. Used for the past three years, the design also consumes 60 percent less energy.

ADOT said that 45 Phoenix-area signs have been retrofitted since 2014 with more to come.

Employees created the system in conjunction with the ADOT’s commitment to continuous improvement. Signs display data about road conditions, highway incidents in the vicinity, and anticipated travel times.