Leading Pedestrian Intervals

2017 ◽  
Vol 2620 (1) ◽  
pp. 96-104 ◽  
Author(s):  
Anuj Sharma ◽  
Edward Smaglik ◽  
Sirisha Kothuri ◽  
Oliver Smith ◽  
Peter Koonce ◽  
...  
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
Signalized Intersections ◽  
Crash Data ◽  
Trade Offs ◽  
Quantitative Metrics ◽  
Traffic Conflicts ◽  
Before And After ◽  
Economic Analyses ◽  
Benefit Cost

To improve the safety of people walking at particular signalized intersections, traffic signal engineers may implement leading pedestrian intervals (LPIs) to provide pedestrians with a walk signal for a few seconds before the parallel vehicular green indication. Previous before-and-after studies and simple economic analyses have indicated that LPIs are low-cost tools that can reduce vehicle–pedestrian conflicts and crashes at some signalized intersections. Despite this evidence, municipalities have little guidance for when to implement LPIs. A marginal benefit–cost framework is developed with quantitative metrics and extends the concept of traffic conflicts and marginal safety–delay trade-offs to analyze the appropriateness of implementing an LPI at specific signalized intersections. The method provides guidance to help quantify the probability of a conflict occurring and direction on whether to implement an LPI at a given location from macroscopic-level inputs, including number of turning movements, crash data, and geometry. A case study with sample data indicated that an LPI was cost-effective for the scenario presented.

Safety Effects of Low-Cost Systemic Safety Improvements at Signalized and Stop-Controlled Intersections

2017 ◽  
Vol 2636 (1) ◽  
pp. 80-87 ◽  
Author(s):  
Thanh Q. Le ◽  
Frank Gross ◽  
Timothy Harmon
Keyword(s):  
South Carolina ◽  
Confidence Level ◽  
Empirical Bayes ◽  
Low Cost ◽  
Cost Effective ◽  
Signalized Intersections ◽  
Cost Ratio ◽  
Data Set ◽  
Benefit Cost Ratio ◽  
Before And After

Packages of intersection treatments—including signing, pavement marking, and signal enhancements—were installed at many signalized and stop-controlled intersections in South Carolina. This study evaluated the overall safety-effectiveness of the concurrent implementation of these systemic low-cost treatments as part of the FHWA Evaluations of Low Cost Safety Improvements Pooled Fund. The data set included both urban and rural three-leg and four-leg intersections with two or four lanes on the major road. The study employed an empirical Bayes before-and-after analysis. The aggregate results indicate reductions for all crash types analyzed in this study. For signalized intersections, the crash modification factors (CMFs) are 0.955, 0.893, 0.974, 0.883, and 0.969 for total, fatal and injury, rear-end, right-angle, and nighttime crashes, respectively. The CMFs for fatal and injury and right-angle crashes are statistically significant at the 95% confidence level and the CMF for total crashes is statistically significant at the 90% confidence level. For stop-controlled intersections, the CMFs are 0.917, 0.899, 0.933, 0.941, and 0.853 for total, fatal and injury, rear-end, right-angle, and nighttime crashes, respectively. All CMFs for stop-controlled intersections are statistically significant at the 95% confidence level. An economic analysis shows that systemic, low-cost intersection treatments are cost-effective with conservative benefit–cost ratio estimates of 4.1 for total crashes at signalized intersections and 12.4 for total crashes at stop-controlled intersections.

Before-and-After Empirical Bayes Evaluation of Citywide Installation of Driver Feedback Signs

2020 ◽  
Vol 2674 (4) ◽  
pp. 419-427
Author(s):  
Mingjian Wu ◽  
Karim El-Basyouny ◽  
Tae J. Kwon
Keyword(s):  
Traffic Safety ◽  
Spatial Data ◽  
Empirical Bayes ◽  
Large Scale ◽  
Low Cost ◽  
Cost Effective ◽  
Before And After ◽  
Feedback Sign ◽  
Driver Feedback ◽  
Road Segments

Speeding is a leading factor that contributes to approximately one-third of all fatal collisions. Over the past decades, various passive/active countermeasures have been adopted to improve drivers’ compliance to posted speed limits to improve traffic safety. The driver feedback sign (DFS) is considered a low-cost innovative intervention that is being widely used, in growing numbers, in urban cities to provide positive guidance for motorists. Despite their documented effectiveness in reducing speeds, limited literature exists on their impact on reducing collisions. This study addresses this gap by designing a before-and-after study using the empirical Bayes method for a large sample of urban road segments. Safety performance functions and yearly calibration factors are developed to quantify the sole effectiveness of DFS using large-scale spatial data and a set of reference road segments within the city of Edmonton, Alberta, Canada. Likewise, the study followed a detailed economic analysis based on three collision-costing criteria to investigate if DFS was indeed a cost-effective intervention. The results showed significant collision reductions that ranged from 32.5% to 44.9%, with the highest reductions observed for severe speed-related collisions. The results further attested that the benefit–cost ratios, combining severe and property-damage-only collisions, ranged from 8.2 to 20.2 indicating that DFS can be an extremely economical countermeasure. The findings from this study can provide transportation agencies in need of implementing cost-efficient countermeasures with a tool they need to design a long-term strategic deployment plan to ensure the safety of traveling public.

scholarly journals Safety Evaluation of Shoulder Bypass Lanes at Unsignalized Intersections on Rural Two-Lane Roadways Using Cross Sectional Analysis

2016 ◽  
Author(s):  
Sunanda Dissanayake ◽  
Alireza Shams
Keyword(s):  
Low Cost ◽  
Safety Evaluation ◽  
Cross Sectional Study ◽  
Highway Safety ◽  
Sectional Study ◽  
Cross Sectional ◽  
Crash Data ◽  
Study Approach ◽  
Unsignalized Intersections ◽  
Before And After

Construction of bypass lanes at rural intersections has typically been considered a low-cost highway safety improvement by the transportation community. However, this needs to be quantitatively evaluated so that the decisions could be made on whether to continue with adding bypass lanes. Highway safety analyses utilize two common approaches to evaluate the effectiveness of a geometric treatment: before-and-after study and cross-sectional study. This paper explains the results using a cross-sectional study approach, where intersections with bypass lanes were compared to intersections with no bypass lanes for which crash data were obtained for more than 1,100 intersections in Kansas. Both 3-legged and 4-legged intersections were taken into consideration separately by looking at intersection-related crashes and crashes within an intersection box. According to the results, the number of crashes and crash severities were lower at 3-legged intersections with bypass lanes compared with 3-legged intersections without bypass lanes, even though these reductions were not statistically significant at 95% level. When considering a 300-ft. intersection box, statistically significant crash reductions were observed at 4-legged intersections, for all considered crash and crash rate categories. When considering 90% level, crash reduction at 3-legged intersections was also statistically significant when considering a 300-ft. intersection box. Crash modification factors (CMFs) calculated to evaluate safety effectiveness of bypass lanes at unsignalized rural intersections in Kansas showed values less than 1.0 for almost all cases, indicating safety benefits of bypass lanes. Accordingly, it is beneficial to continue with the practice of adding shoulder bypass lanes at rural unsignalized intersections on two-lane roads where the traffic volumes are relatively low.

Reliability of Passive UHF RFID Copper Tags on Plywood Substrate in High Humidity Conditions

2016 ◽  
Vol 2016 (NOR) ◽  
pp. 12-16 ◽  
Author(s):  
Erja Sipilä ◽  
Johanna Virkki ◽  
Lauri Sydänheimo ◽  
Leena Ukkonen
Keyword(s):  
Moisture Absorption ◽  
Low Cost ◽  
Cost Effective ◽  
High Volume ◽  
High Humidity ◽  
Uhf Rfid ◽  
Passive Uhf Rfid ◽  
Before And After ◽  
Moist Environment ◽  
Read Range

The growth of the wireless world, especially the increasing popularity of the Internet of Things, has created a need for cost-effective and environmentally friendly electronics. Great potential lies especially in versatile applications of passive UHF RFID components. However, the reliability of these components is a major issue to be addressed. This paper presents a preliminary reliability study of glue-coated and non-coated brush-painted copper tags on a plywood substrate in high humidity conditions. The passive UHF RFID components presented in this paper are fabricated using brush-painting and photonic sintering of cost-effective copper oxide ink directly on a plywood substrate. The performance of the glue-coated and non-coated tags is evaluated through wireless tag measurements before and after high humidity testing. The measurement results show that the copper tags on plywood substrate initially achieve peak read ranges of 7–8 meters and the applied coating does not affect to the read range. Moisture does not prevent the coated tags from working in a tolerable way, although the tag performance slightly temporarily decreases due to the moisture absorption. However, when the moisture exposure is long, the performance degradation comes irreversible. The absorbed moisture decreases the read range of the non-coated tags and the performance does not return back to normal after drying. Hence, the coating improves the reliability of the tags in a moist environment compared to the non-coated tags. Based on our results, the plywood material and the used manufacturing methods are very potential for low-cost, high-volume green electronics manufacturing.

Advanced Substrate Applied Fluxing Underfill for Bonding of Fine Pitch Solder Capped Cu Pillars to Oxidized Cu Substrates

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 000924-000943
Author(s):  
Russell Stapleton ◽  
Jim Greig
Keyword(s):  
Cross Sections ◽  
Flip Chip ◽  
Low Cost ◽  
Cost Effective ◽  
Filler Loading ◽  
Thermal Compression ◽  
Transparent Substrate ◽  
Fine Pitch ◽  
Before And After ◽  
Cu Substrates

Underfill solutions for fine pitch flip chip assemblies is an active area of development. Non-conductive films (NCF) and pastes (NCP) have shown great potential in bridging the gap between no-flow and capillary underfills for improving the reliability of fine pitched devices. But NCFs and NCPs require costly passivated pad finishes (e.g. Au, Sn, Ni, OSP) or careful substrate handling for proper solder joint formation. In this paper, we will describe a new class of underfill material that benefits from the growing trend of using thermal compression bonding as a cost effective alternative to mass reflow based underfilling processes (e.g. capillary and no-flow). This material is a fluxing NCP that is useful for a wide variety of fine pitch substrates, including low cost Cu. The material we will demonstrate contains many advanced features: high filler loading, strong flux activity, long work life, off-tool pre-dispense, low stress, high Tg, high modulus and rapid cure. The all-in-one underfill demonstrated in this paper is applied by using a screen printing process, where the material is applied to all of the chip sites in one step achieving excellent application efficiency and wetting/conformity to the substrate. The substrate is glass, containing a 4x4 array of die sites. Each of the die sites are 5x5mm in size with a full area array of 2501 Cu pads (50um pads on 100um pitch) that are pre-oxidized for 1h at 175C in air prior to printing (to simulate a dehydration bake). This transparent substrate was chosen to show the robust nature of the underfill for fluxing, stability and void-free placement/cure. Images of the substrate, before and after chip bonding will be given, along with cross sections. Details of the material properties will also be discussed.

Safety Effects of Turning Movement Restrictions at Stop-Controlled Intersections

2018 ◽  
Vol 2672 (21) ◽  
pp. 10-19
Author(s):  
Thanh Q. Le ◽  
Frank Gross ◽  
Tim Harmon
Keyword(s):  
Confidence Level ◽  
Cost Effective ◽  
Cross Sectional ◽  
Benefit Cost Analysis ◽  
Crash Data ◽  
Crash Modification Factors ◽  
Design Speed ◽  
Benefit Cost ◽  
Crash Types ◽  
Safety Benefit

This study evaluates the safety effectiveness of physical right-in-right-out (RIRO) operations compared with full turning movements at stop-controlled intersections. Geometric, traffic, and crash data from California were obtained for urban, three-legged, stop-controlled intersections with full movement and RIRO operations, as well as the downstream four-legged, stop-controlled or signalized intersections with full movement. A cross-sectional analysis provided estimates of the effects of turning movement restrictions while controlling for other differences between sites with RIRO and full movement. The aggregate results indicate reductions in total, all intersection-related, and fatal and injury intersection-related crashes at intersections with RIRO operations compared with full movement, with estimated crash modification factors of 0.55, 0.32, and 0.20, respectively. The reductions are statistically significant at the 95% confidence level for all crash types. Based on the disaggregate results, it does not appear that RIRO operations have different effects for different levels of traffic, design speed, or number of lanes. The analysis also examined the potential for crash migration from intersections where RIRO is implemented to the downstream intersection when determining the net benefits. The results indicate potential crash increases at downstream intersections, but many of the increases are not statistically significant at the 90% confidence level. Although the safety benefit-cost analysis suggests the strategy can be cost effective in reducing crashes at stop-controlled intersections, there is a need to analyze potential costs and benefits on a case-by-case basis with site-specific values.

scholarly journals A Simulation Study of the Effect of Injecting Carbon Dioxide with Nitrogen or Lean Gas on the Minimum Miscibility Pressure

2021 ◽  
Author(s):  
Ahmed GH Mansour ◽  
Talal Gamadi ◽  
Hussain R Saoyleh
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
Optimum Concentration ◽  
Cost Ratio ◽  
Gas Mixture ◽  
Benefit Cost Ratio ◽  
Compositional Model ◽  
Minimum Miscibility Pressure ◽  
Gas Flooding ◽  
Benefit Cost

Abstract The objective of this study is to determine the effects of the concentration of injected gases on recovery factors. CO2 has been used for flooding because it requires low injection pressures to achieve miscibility. However, the availability of CO2 is an issue. CO2 required for the process is not sufficient for the reservoir under consideration. Moreover, its benefit-cost ratio (b/c) represents another issue; higher volumes of CO2 increases the economic expenditures. An alternative is to inject lean gas or nitrogen along with CO2 to achieve better recoveries at optimum costs and suitable pressure. Slim tube simulation using a commercial simulator is utilized to measure the minimum miscibility pressure (MMP) of an injected gas mixture. The mixture contains CO2/N2 or CO2/lean gas. Using different concentrations in the injected mixture, an effect on the recovery factor is studied. The first 30 runs have 100% concentration of each individual gases i.e. N2, CO2 and lean gas. Based on these runs, the simulation model is validated using the co-relations present in the literature. Gas mixtures of CO2/N2 and CO2/lean gas were then simulated using the compositional model to test the effect on MMP by varying the concentration of each gas in the mixture. By changing the volumes of the gas in the injected mixture, we can find the optimum concentration of each component in the mixture in terms of MMP. From the results obtained through simulation, it can be deduced that higher percentages of CO2 in the mixture would result in reduced minimum miscibility pressure. The addition of a secondary slug to the injected CO2 fluid increases the pressure required to achieve miscibility. Of N2 and Lean gas, Lean gas provided better results as it showed low miscibility pressure responses compared to the same amount of N2 gas. For example, for a case, 50% CO2 and 50 %N2 or lean gas mixture, the MMP for the lean gas mixture is 3500 Psi, while for N2 mixture it was 4667 Psi. However, lean gas is expensive as compared to N2 and N2 is easily available. N2, if used in optimum concentration along with CO2 can produce greater recoveries keeping the process cost-effective while satisfying other constraints. CO2 is widely used for miscible injection, but it presents problems like costs, corrosion, and asphaltene deposition etc. The study can give an idea of the success of carrying out EOR through gas flooding by using N2 and CO2 to enhance recovery at low cost. N2 is easily available from air and it is cheap.

Design and Fabrication of Microfluidics Paper-Based Devices for Contaminant Detection Using aWax Printer

2021 ◽  
Vol 2021 (16) ◽  
pp. 339-1-339-8
Author(s):  
Qiyue Liang ◽  
Min Zhao ◽  
George T. C. Chiu ◽  
Jan P. Allebach
Keyword(s):  
Image Processing ◽  
Microfluidic Device ◽  
Low Cost ◽  
Cost Effective ◽  
Back Side ◽  
Minimum Width ◽  
Before And After ◽  
Wax Printing ◽  
Multiple Devices ◽  
Processing Techniques

In this paper, we introduce an eight-channel paper-based microfluidic device that aims to detect multiple chemicals at once. The microfluidic device we propose is fabricated by wax printing on filter paper, which is trouble-free to handle, low cost, and easy to fabricate. As a hydrophobic material, wax (solid ink) defines the hydrophilic channels for testing. By using image processing techniques, we analyze the width change caused by heating of wax strokes and wax channels, which is a necessary step in the wax printing fabrications. In the same way, we test the minimum width of a channel that allows solutions to cross through and the minimum width of a barrier that is hydrophobic and blocks liquid flow. We also compare two different heating methods, the heat gun and the hot plate, by checking the wax channel width before and after heating based on our image processing pipeline. We conclude that a heat gun will be better for heating channels with relatively large widths. Using high resolution wax printing, we integrate multiple devices on a single paper, which makes this method very cost-effective. Lamination of wax-printed paper based devices is also analyzed, as leakage on the back side of paper is sometimes worth attention.

Comparison of Traffic Conflict Indicators for Crash Estimation using Peak Over Threshold Approach

2019 ◽  
Vol 2673 (5) ◽  
pp. 493-502 ◽  
Author(s):  
Lai Zheng ◽  
Tarek Sayed
Keyword(s):  
Confidence Intervals ◽  
Signalized Intersections ◽  
Estimation Methods ◽  
Crash Data ◽  
Time To Collision ◽  
Considerable Research ◽  
Traffic Conflicts ◽  
Peak Over Threshold ◽  
Traffic Conflict ◽  
Threshold Approach

Traffic conflict techniques have drawn considerable research interest and a number of conflict indicators have been developed. Previous studies have qualitatively analyzed indicator differences from their definitions and empirically investigated their similarities based on identified traffic conflicts. This study compares conflict indicators from a validity perspective by comparing crashes estimated from conflict indicators with observed crashes. The peak over threshold (POT) approach was employed for crash estimation. Four commonly used indicators are compared: time to collision (TTC), modified time to collision (MTTC), post encroachment time (PET), and deceleration to avoid a crash (DRAC). Based on the conflict and crash data collected from three signalized intersections, POT models are developed for different thresholds in the appropriate ranges, and crash estimation methods were proposed for individual conflict indicators. The identified conflicts and estimated crashes associated with different indicators are then compared. The results show that traffic conflicts identified by the four indicators vary, with MTTC generating the most accurate crash estimates. The crash estimates from TTC and PET are also reasonable but there is a tendency of overestimation for TTC and underestimation for PET. The crash estimates of DRAC are all outside the confidence intervals of observed crashes, which is likely related to the uncertainty of vehicle braking capacity.

scholarly journals Pelleting Vineyard Pruning at Low Cost with a Mobile Technology

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2477 ◽  
Author(s):  
Giuseppe Toscano ◽  
Vincenzo Alfano ◽  
Antonio Scarfone ◽  
Luigi Pari
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
Point Of View ◽  
Production Costs ◽  
Direct Production ◽  
Economic Point ◽  
Before And After ◽  
Variable Distance ◽  
Intermediate Storage

The goal of this work was to test a patented pruning harvester and a mobile pelleting system specifically designed for the vineyard agripellet chain. Biomass was characterized before and after storage and after the pelleting stage. The performance, the fuel consumption, and the work quality of the harvester were assessed together with the productivity and the power consumption of the mobile pelleting system. Production costs of pellet were estimated for the whole logistic chain, considering two scenarios: Storage and pelleting directly at the farm site or at a dedicated location at variable distance from the fields. For comparison, the direct production of chips without pelleting was considered. Results indicate that harvester performance was quite good and comparable with commercial solutions; the chips produced exhibited excellent storage performance, allowing direct pelleting without forced drying; the pellet quality was good comparable with that produced from forestry biomass. From an economic point of view, in-field pelleting was the most cost-effective solution, with a good margin of profit up to 57€ t−1; on the other hand, when transport to an intermediate storage center is necessary, profit margin reduces gradually and fades off at an average 50 km distance from the fields.

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