The Ada County Highway District is nearly finished with a project to switch all traditional light bulbs in roughly 400 traffic signals across the district to energy-efficient light emitting diodes. That means there are more than 18,000 of the high-tech lights guiding area traffic.
ACHD spokeswoman Robbie Johnson said nearly all the traffic signals in the county have now been converted and just a few of the pedestrian signals have yet to be transitioned.
Johnson said the project has the bonus effect of improved safety since road crews don't have to impede traffic to change the bulbs as often.
Of course, there's always a trade-off. The LED lights cost significantly more—$40 a pop compared to just a few dollars for a standard light bulb.
The new lights use one-tenth of the energy of regular bulbs (780,000 kilowatt hours compared to 7,800,000 kilowatt hours), but put out more light and last longer (five years rather than two years).
The energy savings is enough to power 557 homes for a year, according to Idaho Power.
ACHD officials are quick to point to the potential savings in energy expenditures. Yearly energy costs to power conventional lights would run roughly $390,000, while the LED lights will cost roughly $39,000 per year.