From Tech Transfer Newsletter, Spring 2006 » printer-friendly

Toward Sustainable Transportation

California Converts to LED Traffic Signals

By Jackalyne Pfannenstiel, Vice Chair, California Energy Commission

California law now requires traffic signals in the state to be energy efficient—so energy efficient that only light emitting diodes (LED) lamps meet the new standard.

In 2002, the California Energy Commission adopted standards for vehicular traffic signal lamps and modules, adding pedestrian signal lamps in 2004. As cities and counties convert to the more efficient lamps, 35 local agencies have been awarded nearly $9.4 million in loans from the Energy Commission to help them with their improvements. LED technology has reduced California local agenciesí utility bills by more than $2 million annually.

The reason for the savings is simple—traditional incandescent lamps are a very inefficient light source. Since most of the energy goes to produce unneeded heat rather than actual light, incandescent traffic signals consume 80 to 90 percent more electricity than those using LED technology.

Michael Grimes, Facilities Manager of the City of Santa Barbara, reports 70 to 80 percent savings in electricity costs as a result of converting all their traffic signal lamps to LEDs. The Energy Commission staff estimates that the city's electricity costs for traffic signals dropped from $155,000 a year with incandescents to about $17,000 with the new LED lamps. Electricity use went from 1.4 million to 150,000 kilowatt hours (kWh) a year. He states that since the different color LED clusters wear out at different rates, the city can also spread out replacement costs over several years.

What California Standards Require

Currently, only LED traffic signal modules meet the requirements. A list of certified traffic signal modules can be downloaded in Zip format from the Energy Commission's website at: www.energy.ca.gov/appliances/ appliance/excel_based_files/traffic_signals.

State Funding

California has $40 million to loan to local governments to help them with energy efficiency projects, including the retrofit of traffic signals. The interest rate is 4.5 percent (4.1 percent in some cases). An application can be downloaded from the Energy Commission's website at: www.energy.ca.gov/efficiency/financing.

This article is reprinted with permission from WesternITE, the official publication of District 6 of the Institute of Transportation Engineers.

© 2009 Regents of the University of California