Traffic Signals


Traditionally, traffic signals use long-life incandescent bulbs. However, these lights have high operating hours, making energy use high. 


In recent years, LED (light emitting diode) traffic signals have been introduced that reduce energy use by about 90% relative to incandescent lights.  The LED signs were promoted by the Energy Star program and many utility and state programs.  California and other states adopted standards, setting watt caps of 8-13 watts for each ball (red or green) or face (e.g., walk signal) when tested at 25 degrees C. This essentially requires use of LED lights.  Congress made this a national standard in 2005, with the standard taking effect in January 2006.  Yellow balls can still be incandescent since they have very low operating hours.

Projected Savings

Traffic Signal Standards of 2005
Savings through what year?:
Energy saved (quads):
CO2 savings (million metric tons):
Net present value savings ($billion) 3% discount rate:
Net present value savings ($billion) 7% discount rate:


Federal Date States
2008 AZ Standard Effective *
2007 WA Standard Effective *
2007 NJ Standard Effective *
2007 RI Standard Effective *
2007 OR Standard Effective *
2006 CT Standard Effective *
2006 CA Standard Effective *
1st Federal Standard Effective 2006
2005 MD Standard Effective
1st Federal Standard Adopted (Congress) 2005
EPACT Initial Federal Legislation Enacted 2005
2005 WA Standard Adopted
2005 NJ Standard Adopted
2005 AZ Standard Adopted
2005 RI Standard Adopted
2005 OR Standard Adopted
2005 NY Standard Adopted
2004 CT Standard Adopted
2004 MD Standard Adopted
2004 CA Standard Adopted
2003 CA Standard Effective
2002 CA Standard Adopted

* State standard never went into effect due to preemption by federal standard.

States not showing an effective date have an ongoing rulemaking process to determine standards.

Timeline reflects state standards from 2001 to present; federal standards from inception to present.