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Energy Efficiency for Traffic Signals

Last modified: 3/6/2012 2:47 PM
Red, Yellow and Green LED DevicesThe County of Santa Clara undertook a program to improve the energy efficiency of its traffic signal systems in the summer of 1998. The costs for energy to operate traffic signals were rising and the County was interested in minimizing those costs. The use of energy efficient LED technology can reduce energy consumption by up to 90% for the average traffic signal indications. The savings in energy costs and the availability of rebates from PGE were considered when making the decision to retrofit all the red light and pedestrian "hand" signals. With an estimated life of 10 years, savings in maintenance costs would also be realized.

In the fall of 2000, the County was able to take advantage of new rebate programs offered by PGE and the California Energy Commission (CEC) to complete the greens and Pedestrian "Walking Man" signals. The County also decided to replace the yellow signals, as well, to minimize maintenance costs. Installation started in late March of 2001 and was completed by June. Due to material shortages, a few signal systems remain to be completed. 97% of the PGE signals and 89 % of the non-PGE signals were completed. All signals will be completed by the end of September 2001.

With the recent energy shortages being experienced, it confirms the need for this type of improvement. After the original retrofit of just the red lights, energy consumption was reduced by 50%. The recent retrofit of the greens and yellows reduced the energy consumption to a 90% reduction overall. With the reduction in energy needs, we also get an additional benefit of being able to operate the signal on Uninterruptible Power Systems (UPS) at a reasonable cost. With the rolling blackouts we may experience this summer, the need for these systems has been highlighted. We are undertaking the installation of several UPS systems this summer and planning an overall program for all signal systems in the near future as funds become available.