Warning Light Flash Frequency as a Method for Visual Communication to Drivers

2021 ◽  
pp. 036119812098332
Author(s):  
Nicholas P. Skinner ◽  
Timothy T. LaPlumm ◽  
John D. Bullough
Keyword(s):  
Laboratory Study ◽  
Visual Communication ◽  
Light Flash ◽  
Work Zone ◽  
Warning Light ◽  
Potential Risks ◽  
Photosensitive Epilepsy ◽  
Warning Lights ◽  
Service Vehicles

Service vehicles use flashing warning lights to indicate their presence to approaching drivers. Present standards offer ranges of flash frequencies to enhance conspicuity and avoid potential risks of photosensitive epilepsy or other issues. But, in practice, the flash frequency is not varied in specific situations. Previous studies have indicated that people interpret faster flash frequencies as more “urgent” than slower flash frequencies. Building on these findings, a laboratory study was conducted to identify whether drivers might be able to use cues from the frequency of flashing warning lights to anticipate how a service vehicle might behave in a work zone or other incident scene. The results suggest that even if they are not taught about the interpretation of different flash frequencies, drivers can differentiate between 1 Hz and 4 Hz flashing lights and learn to make accurate predictions about their meaning. The results also indicate that there are no reliable differences between 1 Hz and 4 Hz flashing in relation to a driver’s ability to detect when a service vehicle has begun to move. Based on the results, a preliminary suggestion is made to use lights flashing at 1 Hz when a service vehicle is moving forward, and 4 Hz when it is traveling in reverse.

scholarly journals Toward the development of standards for yellow flashing lights used in work zones

2016 ◽  
Vol 50 (4) ◽  
pp. 552-570 ◽  
Author(s):  
MS Rea ◽  
JD Bullough ◽  
LC Radetsky ◽  
NP Skinner ◽  
A Bierman
Keyword(s):  
Field Study ◽  
Work Zone ◽  
Luminous Intensity ◽  
Work Zones ◽  
Driver Safety ◽  
Visual Discomfort ◽  
Directional Information ◽  
Warning Light ◽  
Warning Lights ◽  
Current Standards

Flashing yellow warning lights are important for worker and driver safety in work zones. Current standards for these lights do not address whether and how they should be coordinated to provide directional information to drivers navigating through work zones. A field study was conducted to assess driver responses to warning lights. The luminous intensities and flash patterns of warning lights along a simulated work zone were varied during daytime and nighttime. During the daytime, driver responses were relatively insensitive to warning light characteristics, although drivers preferred sequential and synchronised flash patterns over random, uncoordinated flashing. At nighttime, the combination of a temporal peak luminous intensity of 25 cd and a sequential flash pattern was optimal for providing directional information. A single initial warning light having a higher luminous intensity may help drivers detect the work zone without creating unacceptable visual discomfort.

Effectiveness of Green Warning Lights with Different Flashing Patterns for Winter Maintenance Operations

2021 ◽  
pp. 036119812110081
Author(s):  
Fatemeh Fakhrmoosavi ◽  
Ramin Saedi ◽  
Farish Jazlan ◽  
Ali Zockaie ◽  
Mehrnaz Ghamami ◽  
...  
Keyword(s):  
Human Subjects ◽  
Test Results ◽  
Night Time ◽  
Winter Maintenance ◽  
Warning Light ◽  
Rigorous Study ◽  
Static Versus Dynamic ◽  
Color Combinations ◽  
Warning Lights ◽  
Pavement Friction

Snow removal activities are performed by roadway agencies to enhance winter mobility and safety. Slower travel speeds during these operations, combined with low visibility and reduced pavement friction, mean that safety and collision avoidance remain a persistent concern. Many studies have implemented signing and lighting technologies to improve the visibility of snowplows. Although a few studies have evaluated the use of different colors on snowplows, there is no rigorous study that evaluates the potential impacts of using green warning lights for winter maintenance operations. This study, therefore, investigates the impacts of various warning light configurations on the visibility of snowplows, with the focus on green lights. To this end, 37 warning light configurations are designed using various color combinations (green and amber), and flashing patterns (single and quad) on the back (LED), the top (beacon), or both, of snowplows. These configurations are evaluated to identify the most effective configurations. Three sets of experiments are designed and implemented: static, dynamic, and weather to evaluate the visibility effectiveness in different contexts: day versus night, clear versus snowy weather, and static versus dynamic scenarios. Human subjects are employed to conduct the experiments and the test results are evaluated using statistical analyses. The conspicuity during the day time and glare during the night time are statistically different among various configurations. In addition, adding green lights with a single flash pattern to amber warning lights improves the conspicuity, while keeping the glare at an acceptable level relative to configurations using only amber.

Driver Behavior in Response to Flashing Lights

2019 ◽  
Vol 2673 (5) ◽  
pp. 703-708 ◽  
Author(s):  
Kristin Kersavage ◽  
Nicholas P. Skinner ◽  
John D. Bullough ◽  
Philip M. Garvey ◽  
Eric T. Donnell ◽  
...  
Keyword(s):  
Driver Behavior ◽  
Sequential Pattern ◽  
Work Zone ◽  
Lane Change ◽  
Work Zones ◽  
The Road ◽  
The Individual ◽  
The Right ◽  
Warning Lights ◽  
Current Standards

Flashing yellow warning lights notify drivers about the presence of work along the road. Current standards for these lights address performance of the individual light but not how lights should function when multiple lights are used. In the present study, warning lights were used to delineate a lane change taper in a simulated work zone. Lights flashed with varying intensities and either randomly or in sequence, with lights flashing in turn along the length of the lane change taper, either to the right or to the left. In half of the trials, a flashing police light bar was used on a vehicle located within the simulated work zone. Participants were asked to drive a vehicle approaching the work zone and to identify, as quickly as possible, in which direction the taper’s lane change was (either to the right or left). Drivers were able to correctly identify the taper from farther away when the lights flashed in a sequential pattern than when the flash pattern was random; and the presence of a police light bar resulted in shorter identification distances. The results, along with previous research, can inform standards for the use of flashing lights and police lights in work zones for the safety of drivers and workers.

scholarly journals Sequential Warning-Light System for Work-Zone Lane Closures

2001 ◽  
Vol 1745 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Melisa D. Finley ◽  
Gerald L. Ullman ◽  
Conrad L. Dudek
Keyword(s):  
Work Zone ◽  
Warning Light ◽  
Light System ◽  
Lane Closures

Differences in Nighttime Luminance of Work Zone Drums with and without Steady-Burn Warning Lights

2011 ◽  
Vol 2258 (1) ◽  
pp. 16-24
Author(s):  
Timothy J. Gates ◽  
Peter T. Savolainen ◽  
Tapan K. Datta ◽  
Prasad Nannapaneni
Keyword(s):  
Work Zone ◽  
Warning Lights

Trace element leaching from contaminated willow and poplar biomass – A laboratory study of potential risks

2018 ◽  
Vol 112 ◽  
pp. 11-18 ◽  
Author(s):  
Kateřina Břendová ◽  
Pavla Kubátová ◽  
Jiřina Száková ◽  
Pavel Tlustoš
Keyword(s):  
Trace Element ◽  
Laboratory Study ◽  
Potential Risks

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

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