A Comparison between the Turn On and Turn Off Characteristics of Incandescent and LED Traffic Signal Modules

Benekohal, Rahim F.; Girianna, Montty; Chitturi, Madhav V.

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https://hdl.handle.net/2142/46273 Copy

Description

Title

A Comparison between the Turn On and Turn Off Characteristics of Incandescent and LED Traffic Signal Modules

Author(s)

• Benekohal, Rahim F.
• Girianna, Montty
• Chitturi, Madhav V.

Issue Date

2003-12

Keyword(s)

Light Emitting Diodes, LED Traffic Signal Modules, Incandescent modules, Turn on and Turn off characteristics, Fade in and Fade out times,Traffic Signal, Driver Perception, Intersection Traffic Lights.

Abstract

Illinois Department of Transportation (IDOT) has been replacing the incandescent traffic signal modules with LED modules at various intersections. Using LED modules from different manufacturers on the same intersection approach may create an unsynchronized turn on and turn off characteristics that may be noticeable to some motorists. The objective of this study was to compare the turn on and turn off characteristics of incandescent and LED modules. Data was collected and analyzed to determine the turn on and turn off characteristics of incandescent and LED (Gelcore and Dialight) traffic signal modules. Several measures to quantify the signal modules’ characteristics were introduced. These measures included fade in and fade out times, turn on and turn off delay, overlaps/gaps of colors between consecutive phase intervals. For all colors, the LED lenses had shorter fade in times when compared with the incandescent lens. The fade in time for LED Dialight was shorter than that for LED Gelcore, for all the three colors. For solid green, the LED Dialight lens had the longest fade out time. For yellow and red, the LED Dialight lenses had shorter fade out times when compared to the other two lenses. For solid yellow and red, the incandescent lens had the longest fade out time. Except for LED Dialight solid red, all LED lenses turned on a fraction of second later than the corresponding incandescent lenses. LED Dialight solid red lens turned on earlier than the incandescent solid red lens. Except for LED Gelcore solid green lens all the LED lenses turned off a fraction of second earlier than the corresponding incandescent lenses.

Series/Report Name or Number

FHWA-IL/UI-TOL-6

ISSN

0917-9191

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/46273

Sponsor(s)/Grant Number(s)

The Illinois Department of Transportation

Copyright and License Information

No restrictions. This document is available to the public through the National Technical Information Service, Springfield, Virginia 22161

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