Work Zone Lighting and Visual Performance

2013 ◽  
Vol 2337 (1) ◽  
pp. 25-34 ◽  
Author(s):  
John D. Bullough ◽  
Ute C. Besenecker ◽  
Jeremy D. Snyder ◽  
Nicholas P. Skinner
Keyword(s):  
Older Workers ◽  
Full Scale ◽  
Performance Model ◽  
Work Zone ◽  
Visual Performance ◽  
Light Levels ◽  
Lighting Systems ◽  
Control Light ◽  
Computational Analyses

In part because of the potential for high levels of glare from work zone illumination, recommendations for light levels from work zone illumination systems are substantially higher than for levels used along roadways in non–work zone locations. In a two-part study, requirements for work zone illumination light levels were assessed. First, levels for workers varying in age from 20 to 60 years were evaluated with the relative visual performance model, with and without the presence of visibility-reducing glare. Except for the smallest, lowest-contrast tasks performed by the older workers, an illuminance of 10 lx resulted in visibility well above the threshold even in the presence of glare, and an illuminance of 30 lx resulted in suprathreshold visibility for these conditions as well. The results of these computational analyses were largely confirmed in a full-scale, outdoor field demonstration attended by transportation agency engineers and highway contractors. Together, the findings suggest that when lighting systems provide sufficient glare control, light levels do not always need to be especially high to ensure adequate visibility for workers.

scholarly journals Effect of Work Zone Lighting on Drivers’ Visual Performance and Perceptions of Glare

2017 ◽  
Vol 2617 (1) ◽  
pp. 44-51 ◽  
Author(s):  
Rajaram Bhagavathula ◽  
Ronald B. Gibbons
Keyword(s):  
Detection Task ◽  
Construction Workers ◽  
Work Zone ◽  
Visual Performance ◽  
Department Of Transportation ◽  
Work Zones ◽  
Light Levels ◽  
The Impact ◽  
Virginia Smart Road ◽  
The U.S

Nighttime crashes at work zones are major concerns for construction workers and motorists. Although in a majority of the U.S. states, department of transportation specifications for work zone lighting mention that contractors should reduce glare for workers and drivers, only two states advocate detailed specifications like light positions, orientation, and light levels. Although some studies have examined the impact of glare from work zone lights on workers and others have calculated veiling luminance levels for drivers in the work zone, the effect of work zone lighting on drivers’ visual performance and glare perception has never been studied in a realistic setting. The goal of this study was to understand the impact of commercially available portable light towers (metal halide, LED, and balloon) and their orientation on drivers’ visual performance and their perceptions of glare. Participants drove through a realistic work zone simulated on the Virginia Smart Road. Visual performance was assessed by a detection task and perception of visibility and glare were assessed by questionnaires. Results indicated that the type of light tower and its orientation affect visual performance and perceptions of visibility and glare. Light towers aimed toward the driver resulted in lowering drivers’ visual performance, both objectively and subjectively. When the light towers were aimed away from or perpendicular to the driver, the visual performance was higher and the differences in visual performance between the types of light towers were minimal. These findings indicate that these orientations should be preferred for work zone light towers.

scholarly journals LEGIBILITY OF URBAN HIGHWAY TRAFFIC SIGNS USING NEW RETROREFLECTIVE MATERIALS

Transport ◽  
2010 ◽  
Vol 25 (3) ◽  
pp. 229-236 ◽  
Author(s):  
John D. Bullough ◽  
Nicholas P. Skinner ◽  
Conan P. O’Rourke
Keyword(s):  
Urban Area ◽  
Performance Model ◽  
Visual Performance ◽  
Practical Significance ◽  
Department Of Transportation ◽  
Highway Traffic ◽  
Traffic Signs ◽  
Photometric Measurements ◽  
Highway Signs

Unlighted highway signs, which use newly developed retroreflective materials, were installed along the major expressway in an urban area by the local department of transportation. Photometric measurements of the signs were used to assess their legibility applying the relative visual performance model, in comparison to lighted signs, con‐ forming to recommended illumination practices. The calculated visibility of the measured unlighted signs was similar to that of the signs equipped with exterior sign illumination. The practical significance and limitations of the relative visual performance approach are discussed.

Analysis, simulation, and implementation of a human-inspired pole climbing robot

Robotica ◽  
2011 ◽  
Vol 30 (2) ◽  
pp. 279-287 ◽  
Author(s):  
A. Sadeghi ◽  
H. Moradi ◽  
M. Nili Ahmadabadi
Keyword(s):  
Static Analysis ◽  
Full Scale ◽  
The Other ◽  
Light Weight ◽  
Simple Design ◽  
Climbing Robot ◽  
Full Size ◽  
Control Light ◽  
The Stability ◽  
Novel Design

SUMMARYIn this paper, we present the design, static analysis, simulation, and implementation of a novel design for a naturally stable climbing robot that has been inspired from human pole/tree climbers. The other benefits of this robot, besides being naturally stable, are its simple design, ease of control, light weight, simple mechanism, and fast climbing speed. The robot consists of three wheels, two free and one active wheel, which enable the robot to climb or descend poles. The free wheels are almost frictionless, while the active wheel has enough friction to be able to apply force on the pole for stable climbing or descending. The wheels are designed in V-shape such that the robot can compensate for misplacements eliminating possible detachment from poles. Although the robot can operate with a single free wheel, however, an extra free wheel is added to increase the stability and safety of the robot. In this paper, the static analysis of the robot is presented and the robot is simulated. Furthermore, the robot is actually implemented and successfully tested in two sizes, a small size and a big/full size. The full-scale prototype has been equipped with washing and inspection tools and tested washing actual street lights. The results show the unique characteristics of this robot that make it more stable if more weight is carried.

Human visual performance model for crewstation design

1991 ◽  
Author(s):  
James O. Larimer ◽  
Michael P. Prevost ◽  
Aries R. Arditi ◽  
Steven Azueta ◽  
James R. Bergen ◽  
...  
Keyword(s):  
Performance Model ◽  
Visual Performance

Lighting System Preferences for VDT Stands with LCD Screens

2000 ◽  
Vol 44 (21) ◽  
pp. 3-499-3-499
Author(s):  
Agnieszka Wolska
Keyword(s):  
Visual Performance ◽  
Lighting System ◽  
Dark Light ◽  
Lighting Conditions ◽  
Different Types ◽  
Lighting Systems ◽  
New Generation

There are different types of lighting systems suitable for VDT work, which create different interior appearances with respect to the main lighting parameters at the recommended levels at the same time. A new generation of VDT screens, flat panels, which produce the image on the screen in a completely different way, may demand different lighting conditions than CRT screens. The aim of the study was to model different lighting systems for VDT work with LCD screens and their influence on the users' preferences and visual performance. The results of the study showed that the most preferred lighting system for VDT work with LCD screens is direct lighting realized by “dark-light” luminaires.

scholarly journals Roadway Lighting’s Effect on Pedestrian Safety at Intersection and Midblock Crosswalks

2021 ◽  
Author(s):  
Rajaram Bhagavathula ◽  
◽  
Ronald Gibbons ◽  
Andrew Kassing ◽  
◽  
...  
Keyword(s):  
Pedestrian Detection ◽  
Positive Contrast ◽  
Pedestrian Safety ◽  
Light Level ◽  
Lighting Design ◽  
Visual Performance ◽  
Light Levels ◽  
Disability Glare ◽  
Safety Countermeasures ◽  
Pedestrian Crossing

This study evaluates the visual performance of four intersection lighting designs and five midblock crosswalk lighting designs along with two pedestrian safety countermeasures (rectangular rapid flashing beacons and flashing signs) at three light levels. The study involved a pedestrian detection task, which was completed at night on a realistic roadway intersection and a midblock crosswalk. The results from the study showed that driver nighttime visual performance at intersection and midblock crosswalks was influenced by the lighting design and light level. Intersections should be illuminated to an average horizontal illuminance of 14 lux (1.3 fc). This light level ensures optimal visibility of pedestrians regardless of the lighting design (or luminaire layout) of the intersection. The average horizontal illuminance of 14 lux (1.3 fc) also increases the visibility of pedestrians when glare from oncoming vehicles is present. The 14 lux (1.3 fc) average horizontal illuminance is valid for all lighting designs evaluated except the lighting design that illuminated the exits of the intersection. When the exits of the intersection are illuminated, an average horizontal illuminance of 24 lux (2.2 fc) is needed to offset the disability glare from opposing vehicles. Midblock crosswalks should be illuminated to an average vertical illuminance of 10 lux (0.9 fc) to ensure optimal pedestrian visibility. Where overhead lighting is available, midblock crosswalk lighting designs that render the pedestrian in positive contrast are recommended. Where overhead lighting is not available, crosswalk illuminators can be used to illuminate midblock crosswalks. At night, pedestrian crossing treatments such as rectangular rapid flashing beacons and flashing signs should not be used for pedestrian visibility at midblock crosswalks. Pedestrians crossing treatments should be used in conjunction with overhead lighting or crosswalk illuminators at the established vertical illuminance to ensure optimal pedestrian visibility at midblock crosswalks.

Implications of Applying Semi-Scale Pump Test Data to Two-Phase RCP Performance Modeling for PWR LOCA Analyses

2014 ◽  
Author(s):  
Mathew C. Jacob ◽  
Michael T. Coon ◽  
John A. Blaisdell ◽  
Ruben J. Espinosa
Keyword(s):  
Test Data ◽  
Performance Modeling ◽  
Full Scale ◽  
Performance Model ◽  
Performance Data ◽  
Performance Models ◽  
Two Phase ◽  
Coolant Pump ◽  
Pump Performance ◽  
Pump Test

Emergency Core Cooling System (ECCS) analyses using Loss of Coolant Accident (LOCA) codes utilize two-phase Reactor Coolant Pump (RCP) performance models formulated on the basis of data from tests conducted on the Semi-scale pump (Reference 1) operating at 60 Hz frequency. In some PWRs, the RCPs operate at a frequency of 50 Hz. This paper presents the results of an evaluation performed to determine the applicability of RCP two-phase performance models developed on the basis of data from the Semi-scale tests for analyzing ECCS performance of new generation PWRs. The evaluation addressed two major issues: (1) the applicability of the two-phase RCP performance model developed using the data from the Semi-scale pump tests (Reference 1) for full scale Pressurized Water Reactor (PWR) LOCA simulations, and (2) the relevance of the two-phase RCP performance model developed on the basis of test data for the Semi-scale pumps running at 60 Hz frequency to PWR RCPs running at 50 Hz frequency with higher specific speeds. Reviews of pump performance test data available in the open literature identified two-phase performance data appropriate for use in substantiating the validity of current PWR pump performance models. These data supported the conclusion that the two-phase head performance degradation for the Semi-scale Mod-1 pump is conservative compared to the two-phase pump performance data generated from testing of pumps representative of full scale PWR RCPs. A review of ECCS analyses results available in the literature determined that the use of the current RCP two-phase performance model (developed using the Semi-scale Mod-1 pump test data) for a typical PWR plant resulted in about a 100 °F increase in the Peak Clad Temperature (PCT) for a Large Break LOCA (LBLOCA) in comparison to the PCTs calculated using the two-phase pump performance model developed on the basis of test data for pumps representative of full scale PWR RCPs. It was determined from the current study that the frequency (50 Hz vs. 60 Hz) of the electrical power that drives the pump motor is not of much consequence for two-phase RCP performance modeling, since (1) the RCP performance model is characterized via normalized pump performance parameters, and (2) for the LBLOCA analysis of interest, the RCPs are assumed to lose power at the start of the event.

scholarly journals Evaluation of Design and Simulation of Creep Test Rig for Full-Scale Crossarm Structure

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
M. R. M. Asyraf ◽  
M. R. Ishak ◽  
S. M. Sapuan ◽  
N. Yidris ◽  
R. A. Ilyas ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cantilever Beam ◽  
Creep Test ◽  
Full Scale ◽  
Performance Model ◽  
Design Development ◽  
Safety Factors ◽  
Test Rig ◽  
Baseline Model ◽  
Element Analysis

A simulated model was developed in order to design and simulate the mechanical properties of a cantilever beam creep testing rig for a full-scale size crossarm in transmission towers. Currently, the Malaysian power grid system is implementing several materials, such as Chengal wood, polymeric composite, and galvanised steel, as crossarm structures. However, there is a lack of study regarding the long-term mechanical behaviour of heavy structures in the literature. Hence, this article explains the design development of creep test rig for a full-scale crossarm structure using CATIA and mechanical simulation (deformation and safety factors) of the product via ANSYS. The test rig will be used to predict the creep life of the cantilever beam structure. In this study, a tall and large base area structure was designed and replicated from an actual tower to elevate the crossarm above the ground level. In order to select the best performance model, a baseline conceptual test rig was generated in CAD modelling, and the finite element analysis was carried out by using a static structural analysis in ANSYS. Four different bracing configurations were incorporated in the baseline model, and the modified structures were then analysed. The results show that the hybrid bracing configuration has enhanced the mechanical properties and safety factors in the baseline model.

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