Estimating Fatality and Injury Savings Because of Deployment of Advanced Wrong-Way Driving Countermeasures on a Toll Road Network

2021 ◽  
pp. 036119812098657
Author(s):  
Adrian Sandt ◽  
Haitham Al-Deek
Keyword(s):  
Life Cycle ◽  
Capital Investment ◽  
Road Network ◽  
Light Emitting Diode ◽  
Night Time ◽  
Light Emitting ◽  
Limited Access ◽  
Toll Road ◽  
Improved Performance ◽  
Benefit Cost

Limited access facility wrong-way driving (WWD) crashes are typically more severe than other crashes. Deploying advanced WWD countermeasures, such as rectangular flashing beacon (RFB) and light-emitting diode (LED) technologies, at exit ramps can reduce WWD crashes, injuries, and fatalities. No previous research has developed a methodology to quantify the potential fatality and injury savings because of future countermeasure deployments. This paper developed such a methodology and applied it to Florida’s Turnpike Enterprise (FTE) toll road network. From 2011–2016, there were 53 FTE WWD crashes, resulting in 16 fatalities and annual injury costs of $37 million. The proportion of these crashes occurring during night-time was 87%. RFB and LED life-cycle injury savings and costs were determined for all 216 FTE exits. The total savings were $424 million for RFBs (benefit–cost [B/C] ratio of 23.20) and $144 million for LEDs (B/C ratio of 13.13). Deploying countermeasures at the 103 exits with the highest B/C ratios would provide 70% of the total possible savings by equipping 40% of the ramps. For the same capital investment, RFBs provide more savings than LEDs. Spending $1 million to deploy RFBs will provide similar savings as spending $3.4 million to deploy LEDs. Evaluating the existing FTE RFB and LED ramps shows that RFBs are more effective at night-time and can provide three times the savings of LEDs. The results of this paper show the improved performance of RFBs over LEDs and provide an example that other agencies could follow to identify savings and cost-effectively deploy advanced WWD countermeasures.

N-face GaN substrate roughening for improved performance GaN-on-GaN LED

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ezzah Azimah Alias ◽  
Muhammad Esmed Alif Samsudin ◽  
Steven DenBaars ◽  
James Speck ◽  
Shuji Nakamura ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Light Emitting Diode ◽  
Optical Power ◽  
Ammonium Hydroxide ◽  
Content Type ◽  
Light Emitting ◽  
Gan Led ◽  
Improved Performance ◽  
Substrate Roughening

Purpose This study aims to focus on roughening N-face (backside) GaN substrate prior to GaN-on-GaN light-emitting diode (LED) growth as an attempt to improve the LED performance. Design/methodology/approach The N-face of GaN substrate was roughened by three different etchants; ammonium hydroxide (NH4OH), a mixture of NH4OH and H2O2 (NH4OH: H2O2) and potassium hydroxide (KOH). Hexagonal pyramids were successfully formed on the surface when the substrate was subjected to the etching in all cases. Findings Under 30 min of etching, the highest density of pyramids was obtained by NH4OH: H2O2 etching, which was 5 × 109 cm–2. The density by KOH and NH4OH etchings was 3.6 × 109 and 5 × 108 cm–2, respectively. At standard operation of current density at 20 A/cm2, the optical power and external quantum efficiency of the LED on the roughened GaN substrate by NH4OH: H2O2 were 12.3 mW and 22%, respectively, which are higher than its counterparts. Originality/value This study demonstrated NH4OH: H2O2 is a new etchant for roughening the N-face GaN substrate. The results showed that such etchant increased the density of the pyramids on the N-face GaN substrate, which subsequently resulted in higher optical power and external quantum efficiency to the LED as compared to KOH and NH4OH.

scholarly journals Can light emitting diode-based road studs improve vehicle control in curves at night? A driving simulator study

2016 ◽  
Vol 50 (2) ◽  
pp. 266-281 ◽  
Author(s):  
A Shahar ◽  
R Brémond ◽  
C Villa
Keyword(s):  
Driving Simulator ◽  
Light Emitting Diode ◽  
Lateral Position ◽  
Vehicle Control ◽  
Night Time ◽  
Light Emitting ◽  
Road Lighting ◽  
Country Road ◽  
Simulator Study ◽  
Subjective Level

Road delineation treatments enhance the ability of drivers to control their vehicle safely on winding roads. A simulator experiment compared night-time driving on a country road under three conditions: on an unlit road, on a road illuminated on curves by typical road luminaires, and on a road with an active lane delineation application, where self-luminous road studs are turned on to outline the lane and road edges as the driver approaches and passes the curves. The unlit condition induces greater lateral position variability and longer crossovers relative to the studs condition, demonstrating better lateral vehicle control in the latter. The luminaires condition induce greater lateral position variability in left curves, and longer crossovers in right curves, relative to the studs condition, which also demonstrates a better lateral vehicle control in the studs condition. At a subjective level, the participants perceived both the studs condition and the luminaires condition as safer, more comfortable and allowing better control than the unlit road. It was concluded that the tested application enhanced the ability of drivers to control the virtual car, as compared to an unlit road or road lighting.

scholarly journals Comparative Life Cycle Assessment of Lighting Systems and Road Pavements in an Italian Twin-Tube Road Tunnel

2018 ◽  
Vol 10 (11) ◽  
pp. 4165 ◽  
Author(s):  
Giuseppe Cantisani ◽  
Paola Di Mascio ◽  
Laura Moretti
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Light Emitting Diode ◽  
Road Construction ◽  
Road Tunnel ◽  
Light Emitting ◽  
Pavement Materials ◽  
Environmental Consequences ◽  
Lighting Systems ◽  
Reflecting Surface

This work calculates and discusses the Life Cycle Assessment (LCA) of four scenarios composed of two types of road pavements and two types of lighting systems to be built in an Italian twin-tube road tunnel. A 20-year time horizon is adopted to assess the burdens of construction and maintenance of both flexible and rigid pavements and high-pressure sodium (HPS) and light-emitting diode (LED) lamps, traffic, and switching on of lamps. All considered scenarios are comparable with each other in terms of technical performances, but significantly differ regarding their environmental consequences. The geometrical and technical characteristics of the examined scenarios comply with current Italian standards for highways. In all the examined cases, LCA is carried out according to the European standard, EN 15804, and includes 19 impact categories (IC). The analysis demonstrates that the use of more reflecting surface pavement materials (i.e., concrete vs. asphalt) and more performing lighting systems (i.e., LED vs. HPS) can effectively mitigate the deleterious burdens related to road construction, maintenance, and use. For most of the examined ICs, the most environment-friendly scenario has LED lamps and concrete pavement.

Responding to the Wrong-Way Driving Problem with Limited Resources by Optimizing the Placement of Wrong-Way Driving Countermeasure Technologies on Limited Access Facilities

2019 ◽  
Vol 2673 (7) ◽  
pp. 38-49
Author(s):  
Adrian Sandt ◽  
Haitham Al-Deek ◽  
Md Imrul Kayes
Keyword(s):  
Optimization Algorithm ◽  
Road Network ◽  
Cost Effective ◽  
Crash Risk ◽  
New Approach ◽  
Central Florida ◽  
Lone Wolf ◽  
Limited Access ◽  
Toll Road ◽  
Reduction Approach

It can be expensive for agencies to deploy wrong-way driving (WWD) countermeasure technologies on limited access facilities. This paper discusses a WWD crash risk (WWCR) reduction approach to help agencies determine the most cost-effective deployment locations. First, a directional WWCR model identifies roadway segments with high WWCR (WWD hotspots), then two optimization algorithms identify individual exits and mainline sections with high WWCR for priority deployment of WWD countermeasure technologies. This new approach was applied to the Central Florida Expressway Authority (CFX) toll road network to determine priority deployment locations for “Wrong Way” signs with Rectangular Flashing Beacons (RFBs). After modeling each direction of the CFX roadways separately, fifteen WWD hotspot segments were identified. WWCR reduction values were calculated for each exit by determining how far wrong-way vehicles travel based on WWD 911 call data. The exit ramp optimization algorithm was then tested for four investment levels using actual RFB deployment costs and real-world constraints. These optimization results could help CFX better utilize its investment by between 9% and 28% compared with only deploying RFBs at exits in the WWD hotspot segments. The mainline optimization algorithm, which considered the WWCR reduction caused by RFBs already deployed at CFX exit ramps, showed that State Road (SR) 408, SR 417, and SR 528 have mainline sections with high WWCR. These results show how the WWCR reduction approach can help agencies identify WWD hotspot segments and high-WWCR exits not in these segments (lone wolf exits), better utilize their investment, and determine mainline sections with high WWCR.

scholarly journals Multiple night-time light-emitting diode lighting strategies impact grassland invertebrate assemblages

2017 ◽  
Vol 23 (7) ◽  
pp. 2641-2648 ◽  
Author(s):  
Thomas W. Davies ◽  
Jonathan Bennie ◽  
Dave Cruse ◽  
Dan Blumgart ◽  
Richard Inger ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Night Time ◽  
Light Emitting ◽  
Invertebrate Assemblages

scholarly journals Surface/Interface Engineering for Constructing Advanced Nanostructured Light-Emitting Diodes with Improved Performance: A Brief Review

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 821 ◽  
Author(s):  
Lianzhen Cao ◽  
Xia Liu ◽  
Zhen Guo ◽  
Lianqun Zhou
Keyword(s):  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Device Performance ◽  
Interface Properties ◽  
Light Emitting ◽  
Structured Materials ◽  
Light Emitting Devices ◽  
Interface Surface ◽  
Improved Performance ◽  
Low Dimensional

With the rise of nanoscience and nanotechnologies, especially the continuous deepening of research on low-dimensional materials and structures, various kinds of light-emitting devices based on nanometer-structured materials are gradually becoming the natural candidates for the next generation of advanced optoelectronic devices with improved performance through engineering their interface/surface properties. As dimensions of light-emitting devices are scaled down to the nanoscale, the plentitude of their surface/interface properties is one of the key factors for their dominating device performance. In this paper, firstly, the generation, classification, and influence of surface/interface states on nanometer optical devices will be given theoretically. Secondly, the relationship between the surface/interface properties and light-emitting diode device performance will be investigated, and the related physical mechanisms will be revealed by introducing classic examples. Especially, how to improve the performance of light-emitting diodes by using factors such as the surface/interface purification, quantum dots (QDs)-emitting layer, surface ligands, optimization of device architecture, and so on will be summarized. Finally, we explore the main influencing actors of research breakthroughs related to the surface/interface properties on the current and future applications for nanostructured light-emitting devices.

scholarly journals Analyzing Thermal Module Developments and Trends in High-Power LED

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Jung-Chang Wang
Keyword(s):  
Life Cycle ◽  
High Power ◽  
Light Emitting Diode ◽  
Junction Temperature ◽  
Light Emitting ◽  
Consumer Electronic ◽  
High Power Led ◽  
Fin Thickness ◽  
Good Agreement ◽  
Indoor And Outdoor

The solid-state light emitting diode (SSLED) has been verified as consumer-electronic products and attracts attention to indoor and outdoor lighting lamp, which has a great benefit in saving energy and environmental protection. However, LED junction temperature will influence the luminous efficiency, spectral color, life cycle, and stability. This study utilizes thermal performance experiments with the illumination-analysis method and window program (vapour chamber thermal module, VCTM V1.0) to investigate and analyze the high-power LED (Hi-LED) lighting thermal module, in order to achieve the best solution of the fin parameters under the natural convection. The computing core of the VCTM program employs the theoretical thermal resistance analytical approach with iterative convergence stated in this study to obtain a numerical solution. Results showed that the best geometry of thermal module is 4.4 mm fin thickness, 9.4 mm fin pitch, and 37 mm fin height with the LED junction temperature of 58.8°C. And the experimental thermal resistances are in good agreement with the theoretical thermal resistances; calculating error between measured data and simulation results is no more than ±7%. Thus, the Hi-LED illumination lamp has high life cycle and reliability.

scholarly journals Fabrication of centimeter-scale light-emitting diode with improved performance based on graphene quantum dots

2017 ◽  
Vol 10 (3) ◽  
pp. 032102 ◽  
Author(s):  
Chang Xu ◽  
Siwei Yang ◽  
Linfan Tian ◽  
Tianqi Guo ◽  
Guqiao Ding ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Light Emitting Diode ◽  
Graphene Quantum Dots ◽  
Light Emitting ◽  
Improved Performance
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