00464598

Component

http://onlinepubs.trb.org...trr/1987/1111/1111-009.pdf

https://scholar.google.co...cker&publication_year=1987

A method of determining the effective intensity of light flashes composed of multiple pulses (flicks) of light was devised. Detection thresholds were measured for such flashes when the flick frequency and flash duration were varied. Thresholds decreased with increasing flick frequency and flash duration. At each flick frequency the relationship between threshold and flash duration was well characterized by the Blondel-Rey relation (alpha equals 0.2), provided a multiplicative frequency-dependent fitting parameter was chosen. The fitting parameter, beta, increased linearly with frequency between 5 and 20 Hz. A method of determining effective intensity was described that uses the flick frequency, number of flicks, and the calculated effective intensity of a single flick to arrive at the solution. It was concluded that this method should be used for all multiple-flick signals, provided the single-flick duration is less than 0.01 sec and the frequency is between 5 and 20 Hz. The method of Allard should not be used, because it consistently overestimates effective intensity.

Publication of this paper sponsored by Committee on Visibility. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

00496549

pp 71-79

1987

Transportation Research Record

0-309-04463-4

Print

Figures (7) ; References (17) ; Tables (2)

Calculation; Flash point; Flashing traffic signals; Frequency (Electromagnetism)

Computation; Intensity

Highways; Operations and Traffic Management; I73: Traffic Control

TRIS, TRB

Dec 31 1987 12:00AM

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