California Department of Transportation
Coronado Bridge Carquinez Bridge San Francisco/Oakland Bay Bridge Richmond San Rafael Bridge

Materials Engineering and Testing Services

Office of Roadway Materials Testing
Electrical Testing Branch

LED versus Incandescent bulb lighting


This program is geared towards improving the overall efficiency of the traffic signal & lighting  systems designed and constructed by Caltrans. We are continuously working towards improvements to existing traffic signal and lighting systems. Signal & Lighting systems that we are considering has to be safe, energy efficient, low maintenance cost    be safe, energy efficient, low maintenance cost and should have longer life. Keeping in mind the safety of the Maintenance personnel, the systems under development are as follows:

Light Emitting Diodes (LED) Traffic Signals
LED Extinguishable Message Signs
Solar Powered LED Systems
Solar Powered Highway Lighting Systems
Light Pipe Tunnel Lighting Systems

LED Traffic Signal:

Caltrans has retrofitted all Red color traffic signals with Red LED traffic signal modules, the pedestrian signal "Upraised Hand" is also replaced with amber color LED module. The specifications for the following signals were completed and are now included in the July 1999 standard specifications:

300mm Red LED Traffic Signal Modules
200mm Red LED Traffic Signal Modules
300mm Red LED ARROW Signal Modules
Amber LED Pedestrian Signal "Upraised Hand" Modules

Specifications for Green, Yellow, Amber Color LED traffic signal modules and LED combo (Walking Person & Upraised Hand) pedestrian signal module can be found on the internet at following links:

Purchase Specification LED Signal Modules (PDF)
Purchase Specification LED Signal Modules (Combination Pedestrian Signal) (PDF)

LED Luminaires:

Dramatic advances in technology for LED luminaires broadened the applicability of this type of illumination, creating an exciting new option for roadway lighting. Compared to traditional light sources, LED luminaires can deliver longer life, enhanced energy efficiency, lowered maintenance demands and better quality of light. Key advantages of quality LED luminaires include:

Significantly longer lifespan
Lower energy consumption
Reduced maintenance costs
No mercury, lead or other known disposable hazards
Improved night visibility due to higher color rendering, higher color temperature and increased illuminance uniformity

Specifications for LED luminaires can be found on the internet at following links:

Pre-Qualified Product List LED Luminaires (PDF)
Purchase Specification LED Luminaires (PDF)
New Products LED Luminaires Checklist (PDF)


Street Lighting Materials Testing for Office of Purchasing and Contracts (OPAC):

Quality assurance testing for the state furnished highway lighting systems is performed here at the Transportation Laboratory and the following lighting products are eventually stocked at Caltrans headquarter warehouse:

High Pressure Sodium Luminaries
High Pressure Sodium Lamps
Traffic Signal Lamps
Barricade Warning Flashers
6.6 Amp Submersible Type Series Ballast

These items are either furnished on State contracts or are used by Maintenance for re-lamping and retrofitting the existing lighting systems.

Here is a module of Led Lighting vs. Incandescent bulb light. Available for demo at the Lab.

LED versus Incadesent lighting. Available for demo at the Lab

Want to know more about LED's, click here!

Contact:, Transportation Engineer (Electrical)
(916) 227-7112,
Fax (916) 227-7026