Caltrans History of LED Traffic Light Development
In 1995, Caltrans was awarded the California Energy Commission (CEC)
State Energy Award for the Fresno LED field test project. In the same
year, the U.S. Department of Energy awarded Caltrans its National
Energy Award for the same project and for demonstrating low power
solutions for traffic signals. These awards put California's LED
efforts in the national spotlight.
With this national recognition, other agencies got on the LED bandwagon, including the states of New York, Oregon, Vermont and Minnesota and the cities of Denver, Philadelphia, San Jose, Sacramento and San Diego. Many of these governments started red module deployments in 1997 and 1998 that were larger than Caltrans' initial test bed.
California utilities like the Sacramento Municipal Utilities District and Pacific Gas and Electric Company (PG&E) as well as CEC began to recognize the value of LED traffic signals as a viable load management and conservation retrofit. They began to provide co-funding resources for both field testing and/or monitoring of products as well as product rebate incentives. The cost effectiveness of LED signal upgrades started to look "do-able". In the end, Caltrans leveraged $4 million in rebate programs from PG&E, CEC and others to help offset the cost of the LED modules.
After the conclusion of the University of California study, Caltrans was in a position to start assembling a purchase specification. Starting with information from ITE-sponsored efforts, Caltrans put together an aggressive specification that included not only intensity and power requirements but also requirements for allowable total harmonic distortion, power factor and a wide operating temperature range. By fall 1997, this specification was ready for "prime time"; in winter 1998, Caltrans went out for the purchase of 4,000 red ball and arrow modules. From that point on, the specification for red has remained essentially unchanged. This also is the specification that has served as a basis for other colors and configurations of LED modules.
Implementation of a Broad LED Program
Procurement of LED modules also led to some innovations in the way the state of California purchases commodities such as LEDs. After the initial purchases of 18,000 modules in 1998 and 1999, Caltrans decided that the traditional purchase process was too cumbersome. As designed, the process could take up to four to six months from the initial decision to purchase to a finalized purchase order. The California Department of General Services-Procurement Division (DGS/PD) had other methods for multiple purchases of large product quantities.
Caltrans was able to set up multiple master purchase agreements with many LED module vendors. This cut the processing time to less than one month from the initial decision to purchase LED signals.
These master purchase agreements allowed Caltrans to use total cost of ownership criteria to determine the quantities to be ordered from each vendor. As LED module prices come down, energy costs and other life cycle costs become more important than the initial module price.
Deploying LED modules presented other logistical problems as well, most of which were centered around quality assurance issues. Along with learning about LEDs and the other parts that make up LED traffic signal modules, Caltrans had to learn how to test LED modules and what to test for.
The engineers and technicians at the Caltrans Transportation Laboratory developed test procedures and equipment needs. A 44-point test was used on both incandescent and LED indications, but the testing of LED modules required that the test be expanded. For example, temperature can have a dramatic effect on the light output of LEDs. Therefore, 44-point tests needed to be carried out at hot and cold temperatures as well as at room temperature.
The department invested in new test equipment and, most important, a large environmental chamber, which allows Caltrans to test up to 60 LED modules at one time or to test shipments of LED modules as they come in. This investment has proven worthwhile because many manufacturing errors have been discovered. These modules either were replaced or were reworked to meet standards prior to field deployment. This quality assurance effort not only ensures that Caltrans is installing the best material but also helps manufacturers improve their product assembly lines and further improve the quality of material for everyone.
The power of government and a new industry to transform a marketplace
The LED manufacturers stepped in and demonstrated both the power of their newly expanded production capacity and their desire to support the birth of a major new industry in the world.
Within a three-year period, 12-inch red balls decreased from $180 each to the mid- to low-$60s. When bids were opened in January 2001, every color and configuration of LED fixture came in far under previous unit prices. More recent purchases have shown more price reductions. The same 12-inch red balls are now less than $50 and the price of the green modules is even more astounding at less than $100 per unit.
The turn of the century and the power of mass procurement coupled with the lure of the California customer marketplace brought a young industry into full maturity.
While Caltrans' major procurement and implementation effort is nearly complete, the benefits continue:
DIGESTED from Iwasaki, Randell H "LED traffic signal modules as an incandescent lamp alternative". Institute of Transportation Engineers. ITE Journal. Apr 2003. FindArticles.com. 16 Aug. 2008. http://findarticles.com/p/articles/mi_qa3734/is_200304/ai_n9185297
With this national recognition, other agencies got on the LED bandwagon, including the states of New York, Oregon, Vermont and Minnesota and the cities of Denver, Philadelphia, San Jose, Sacramento and San Diego. Many of these governments started red module deployments in 1997 and 1998 that were larger than Caltrans' initial test bed.
California utilities like the Sacramento Municipal Utilities District and Pacific Gas and Electric Company (PG&E) as well as CEC began to recognize the value of LED traffic signals as a viable load management and conservation retrofit. They began to provide co-funding resources for both field testing and/or monitoring of products as well as product rebate incentives. The cost effectiveness of LED signal upgrades started to look "do-able". In the end, Caltrans leveraged $4 million in rebate programs from PG&E, CEC and others to help offset the cost of the LED modules.
After the conclusion of the University of California study, Caltrans was in a position to start assembling a purchase specification. Starting with information from ITE-sponsored efforts, Caltrans put together an aggressive specification that included not only intensity and power requirements but also requirements for allowable total harmonic distortion, power factor and a wide operating temperature range. By fall 1997, this specification was ready for "prime time"; in winter 1998, Caltrans went out for the purchase of 4,000 red ball and arrow modules. From that point on, the specification for red has remained essentially unchanged. This also is the specification that has served as a basis for other colors and configurations of LED modules.
Implementation of a Broad LED Program
Procurement of LED modules also led to some innovations in the way the state of California purchases commodities such as LEDs. After the initial purchases of 18,000 modules in 1998 and 1999, Caltrans decided that the traditional purchase process was too cumbersome. As designed, the process could take up to four to six months from the initial decision to purchase to a finalized purchase order. The California Department of General Services-Procurement Division (DGS/PD) had other methods for multiple purchases of large product quantities.
Caltrans was able to set up multiple master purchase agreements with many LED module vendors. This cut the processing time to less than one month from the initial decision to purchase LED signals.
These master purchase agreements allowed Caltrans to use total cost of ownership criteria to determine the quantities to be ordered from each vendor. As LED module prices come down, energy costs and other life cycle costs become more important than the initial module price.
Deploying LED modules presented other logistical problems as well, most of which were centered around quality assurance issues. Along with learning about LEDs and the other parts that make up LED traffic signal modules, Caltrans had to learn how to test LED modules and what to test for.
The engineers and technicians at the Caltrans Transportation Laboratory developed test procedures and equipment needs. A 44-point test was used on both incandescent and LED indications, but the testing of LED modules required that the test be expanded. For example, temperature can have a dramatic effect on the light output of LEDs. Therefore, 44-point tests needed to be carried out at hot and cold temperatures as well as at room temperature.
The department invested in new test equipment and, most important, a large environmental chamber, which allows Caltrans to test up to 60 LED modules at one time or to test shipments of LED modules as they come in. This investment has proven worthwhile because many manufacturing errors have been discovered. These modules either were replaced or were reworked to meet standards prior to field deployment. This quality assurance effort not only ensures that Caltrans is installing the best material but also helps manufacturers improve their product assembly lines and further improve the quality of material for everyone.
The power of government and a new industry to transform a marketplace
The LED manufacturers stepped in and demonstrated both the power of their newly expanded production capacity and their desire to support the birth of a major new industry in the world.
Within a three-year period, 12-inch red balls decreased from $180 each to the mid- to low-$60s. When bids were opened in January 2001, every color and configuration of LED fixture came in far under previous unit prices. More recent purchases have shown more price reductions. The same 12-inch red balls are now less than $50 and the price of the green modules is even more astounding at less than $100 per unit.
The turn of the century and the power of mass procurement coupled with the lure of the California customer marketplace brought a young industry into full maturity.
While Caltrans' major procurement and implementation effort is nearly complete, the benefits continue:
- Reduced energy consumption (up to 85 percent with all LED modules)
- Reduced maintenance activities (re-lamp cycles increased to five years for red modules and 10 years for others)
- Increased reliability ("burn-out" repairs reduced up to 90 percent, less overtime and lower chance of an indication failing)
- Ability to use battery backup systems economically (a battery
backup system to run an all-LED intersection for two to four hours
costs $3,000 installed)
- Caltrans has had an influence on the LED market. Over the past few years, Caltrans has purchased as many as 30 million individual LEDs. Because of the price reductions, the high brightness LEDs that are used in traffic signals now are economic alternatives in other areas.
Caltrans continues to test new LED modules for inclusion on the LED approved products list. At this time, the department has 120 approved LED modules from 10 manufacturers on the product list.
Caltrans New Products Website: http://www.dot.ca.gov/hq/esc/Translab/NewProducts/index.htm
DIGESTED from Iwasaki, Randell H "LED traffic signal modules as an incandescent lamp alternative". Institute of Transportation Engineers. ITE Journal. Apr 2003. FindArticles.com. 16 Aug. 2008. http://findarticles.com/p/articles/mi_qa3734/is_200304/ai_n9185297
