LEDs on the Key Bridge for their superior vibration resistance

The first phase of the three-year project is about 80 percent completed, with 8,000 new lights in place, said Ted Atwood, director of Baltimore's Department of General Services. Switching the 10,000 city-owned streetlights was the first step. Next up are the lights owned by Baltimore Gas and Electric Co.

For local and state government agencies looking for ways to trim costs, converting street and traffic lights is an opportunity for savings. A study by the Clinton Climate Initiative says streetlights can account for as much as 60 percent of a municipality's electric bill.

Maryland agencies are also making the switch. State officials estimate that LED streetlights have a life span of seven to nine years, versus three to four years for standard sodium vapor lights.

This summer, the Maryland Transportation Authority is testing LED lighting on the Key Bridge as it prepares to replace antiquated fixtures.

"MdTA decided to use LEDs on the Key Bridge for their superior vibration resistance, resulting in less maintenance costs and more energy savings," said spokeswoman Kelly Melhem. "Based on the [outcome] of this pilot testing, we will look at our overall specifications for roadway lighting.