Operating Performance of Diverging Diamond Interchanges

2019 ◽  
Vol 2673 (11) ◽  
pp. 801-812 ◽  
Author(s):  
Michael Hunter ◽  
Angshuman Guin ◽  
James Anderson ◽  
Sung Jun Park
Keyword(s):  
Sensitivity Analysis ◽  
Superior Performance ◽  
Operational Performance ◽  
Second Step ◽  
Traffic Patterns ◽  
Jimmy Carter ◽  
Microscopic Simulation ◽  
Left Turn ◽  
Traffic Volumes ◽  
Diamond Interchanges

As the result of changing traffic patterns, many conventional intersections and interchanges can no longer accommodate growing traffic volumes and heavy turning movements. In response, there are various innovative intersection and interchange designs proposed and implemented to better accommodate these changes, and the diverging diamond interchange (DDI) is one of these alternatives. While there is a significant amount of research on the relative performance of DDIs and conventional diamond interchanges (CDIs), a clear set of guidance on demand conditions under which a DDI is likely an operationally more efficient solution is not readily available. This effort conducts a sensitivity analysis of CDI and DDI operational performance under various interchange lane configurations, including the selected study area of the Jimmy Carter Boulevard and I-85 interchange in Norcross, Georgia, under varying traffic demands and turn-movement ratios. The sensitivity analysis explores the detailed conditions in which one interchange configuration provides superior performance over the other. The sensitivity analysis is structured into a two-step process with a critical lane volume (CLV) analysis as the first step, followed by a VISSIM microscopic simulation study as the second step. Overall, the study found that a CDI is likely to be the preferred option at locations with traffic volumes well below capacity and cross-street left-turn traffic proportions below 30% of the total cross-street demand, and a DDI is likely to be preferred at locations with traffic volumes near capacity and cross-street left-turn proportions exceeding 50% of the total cross-street demand.

Evaluation of a New Intersection Design, “Shifting Movements”

2021 ◽  
pp. 036119812110159
Author(s):  
Ma’en Mohammad Ali Al-Omari ◽  
Mohamed Abdel-Aty
Keyword(s):  
Road Traffic ◽  
Operational Performance ◽  
Microscopic Simulation ◽  
Left Turn ◽  
Traffic Conditions ◽  
Minor Road ◽  
Traffic Volumes ◽  
Average Control ◽  
Traffic Operation ◽  
Intersection Design

Several unconventional designs have been suggested to enhance traffic operation and safety at intersections. However, the operational benefits of implementing some of them are achieved only under certain traffic conditions. For instance, the operational performance of the restricted crossing U-turn (RCUT) intersection design manifests only under highly unbalanced traffic conditions. The RCUT intersection outperforms conventional intersections that are subjected to high major traffic and light minor traffic volumes, while its operational performance fades at intersections with moderate to heavy minor road traffic. In this technical paper, a new innovative four-leg intersection design has been proposed to replace the RCUT intersection under moderate and heavy minor road traffic volumes. The new intersection design which has been named the “Shifting Movements” (SM) intersection has a low number of conflict-points compared with conventional intersections, but similar to the RCUT intersection. Therefore, similar safety benefits are expected to be achieved by the implementation of the SM intersection. Operational evaluations and comparisons between conventional, RCUT, and SM intersections have been conducted in the microscopic simulation environment. Different traffic volume levels and left-turn proportions have been assumed to represent the peak hour with moderate to high left-turn traffic. The results indicate that the SM intersection design significantly outperforms conventional and RCUT intersections that are subjected to high traffic volumes in average control delay and throughput.

scholarly journals Sustainable Design of Diverging Diamond Interchange: Development of Warrants for Improving Operational Performance

2020 ◽  
Vol 12 (14) ◽  
pp. 5840
Author(s):  
Meshal Almoshaogeh ◽  
Hatem Abou-Senna ◽  
Essam Radwan ◽  
Husnain Haider
Keyword(s):  
Performance Comparison ◽  
Simulation Software ◽  
Average Delay ◽  
Innovative Design ◽  
Left Turn ◽  
Conventional Design ◽  
Safety Risks ◽  
Traffic Volumes ◽  
Diamond Interchanges ◽  
Measures Of Effectiveness

Conventional diamond interchanges are facing ever-growing challenges related to traffic operations and safety risks due to increasing traffic volumes and worsening congestions. The agencies are well aware of the high socioeconomic (e.g., user delay cost, fuel cost, and high accident rates) and environmental losses (traffic emissions due to vehicles queuing) associated with the conventional interchange design. This paper provides insight into the different factors that affect the sustainability performance (operational and safety) of a conventional interchange through its redesign into the Diverging Diamond Interchange (DDI) with the increased left-turn demand. It also assesses the need to redesign an interchange to improve the efficiency. Two interchanges that have DDI designs were selected for investigations, and the required data were collected from the relevant agency. The average delay and the capacity were used as the Measures of Effectiveness (MOEs) for data analysis. Numerous factors, that affected these MOEs, were used to design an experiment. This experiment included different levels of volumes, geometric designs, and signal plans. The micro-simulation software (VISSIM 8.0) was employed to calibrate and validate the existing conditions through several steps, including signal optimization and driving behavior parameter optimization. The analysis of the results detected the key thresholds of switching from the conventional design to the innovative design under 90 different scenarios. Finally, the sustainability evaluation of DDI and Conventional Design Interchange was conducted based on their operation and safety performance comparison. The results and findings of this research will act as a guideline for decision-makers regarding when they should consider switching from the conventional interchange design to an innovative design.

scholarly journals Unconventional Intersection Designs for Improving Traffic Operation Along Arterial Roads

2021 ◽  
Author(s):  
Taqwa Hadidi ◽  
Hana Naghawi ◽  
Khair Jadaan
Keyword(s):  
Heavy Traffic ◽  
Travel Speed ◽  
Construction Cost ◽  
Simulation Software ◽  
Signalized Intersection ◽  
Operational Performance ◽  
Microscopic Simulation ◽  
Arterial Road ◽  
Traffic Volumes ◽  
Traffic Operation

The main objective of this paper is to evaluate the effect of implementing four Unconventional Arterial Intersection Designs (UAIDs) including median U-Turn, Superstreet, Jughandle and Single Quadrant Intersection on a major arterial road using SYNCHRO microscopic simulation software. For this purpose, Wadi Saqra Signalized Intersection on Shaker Bin Zaid major arterial road in Amman, Jordan was selected. The simulation results showed that only the Jughandle improved the intersection Level of Service (LOS) slightly, F–E. Nevertheless, the intersection delay was significantly reduced by 64.81%, 76.6%, 91.28% and 75.60% on the proposed Median U-Turn, Superstreet, Jughandle and Single Quadrant unconventional intersection design, respectively. This indicated that these UAIDs don't perform well under heavy traffic volumes. Also, since the Jughandle was the only UAID which improved the LOS on the main intersection, the operational performance of Prince Shaker Bin Zaid arterial after implementing the Jughandle at the main intersection was evaluated including the main intersection: Wadi Saqra intersection, one prior to the main intersection and one after the main intersection. It was found that the use of the Jughandle increased the average travel speed by 35% and decreased the average stopped delay by 28.68% on the arterial road. Also, this paper evaluated the current transportation system and road user's attitude towards UAIDs' implementation through a questionnaire survey. The results indicated high acceptance of UAIDs. Finally, the construction cost for each UAID type was estimated. It was found that the Jughandle had the highest construction cost due to its high acquisition cost.

scholarly journals Impact of using indirect left-turns on signalized intersections’ performance

2017 ◽  
Vol 44 (6) ◽  
pp. 462-471 ◽  
Author(s):  
Mahmoud Taha ◽  
Akmal Abdelfatah
Keyword(s):  
Traffic Control ◽  
Urban Areas ◽  
Signalized Intersections ◽  
Superior Performance ◽  
Operational Performance ◽  
Left Turn ◽  
Traffic Conditions ◽  
Traffic Delays ◽  
The Right ◽  
Transportation Agencies

The majority of traffic delays in urban areas occur at signalized intersections. Due to the limited availability of space and right-of-way, many transportation agencies are considering unconventional traffic control systems for intersections to improve signal efficiency and reduce overall delays. Common unconventional left-turn treatments include the right-turn followed by a U-turn (RTUT) and a U-turn followed by a right-turn (UTRT). The main goal of this study is to determine the traffic operational performance of the three left-turn treatments under different traffic conditions. The results showed that unconventional left-turn control types have less delay and travel time compared to the direct left-turn (DLT), when the U-turn locations are 200 m away from the main intersection. Also, RTUT showed superior performance over the other left-turn control types, when the U-turn locations are 100 m away from the main intersection.

Developing Decision Boundaries for Left-Turn Treatments

2020 ◽  
Vol 2674 (5) ◽  
pp. 315-326
Author(s):  
Michael Adamson ◽  
Grant G. Schultz ◽  
Mitsuru Saito ◽  
Michael D. Stevens
Keyword(s):  
Linear Regression Analysis ◽  
Simulation Models ◽  
Assessment Model ◽  
Final Decision ◽  
Contour Map ◽  
Left Turn ◽  
Contour Maps ◽  
Traffic Volumes ◽  
Decision Boundaries ◽  
Statistical Analysis Software

The purpose of this research was to evaluate the interaction of left-turn and opposing through traffic volumes for permitted and protected left-turn phasing at intersections and develop boundaries that help identify when to switch from permitted to protected phasing at signalized intersections. Permitted phasing allows vehicles to turn left after yielding to opposing vehicles; protected phasing provides an exclusive phase for vehicles to turn left without opposition; and protected-permitted phasing combines these phasing alternatives, allowing both permitted and protected turning movements. Intersections with 1, 2, and 3 opposing-lane configurations with permitted and protected-permitted models (split into green times of 10, 15, and 20 s) were analyzed for a total of 12 simulation models. Each model was divided into 100–225 different volume scenarios, with incremental increases in left-turn and opposing volumes. By exporting trajectory files from VISSIM and importing these into the Surrogate Safety Assessment Model, crossing conflicts for each volume combination in each model were extracted. MATLAB was then used to create contour maps representing the number of crossing conflicts per hour associated with different combinations of left-turn and opposing volume. Basic decision boundaries were examined in each contour map. Statistical analysis software was used to perform a linear regression analysis on transformed data and to develop natural log-based equations that form the decision boundaries for each configuration and phase alternative. These equations were graphed and final decision boundaries developed for the 1-, 2-, and 3-lane configurations between permitted and protected-permitted phasing as well as between protected-permitted and protected phasing.

Bayesian and Sensitivity Analysis Approaches to Modelling the Direct Solar Irradiance

Solar Energy ◽  
2005 ◽  
Author(s):  
Philippe Lauret ◽  
Mathieu David ◽  
Eric Fock ◽  
Laetitia Adelard
Keyword(s):  
Neural Network ◽  
Sensitivity Analysis ◽  
Solar Irradiance ◽  
Second Step ◽  
Practical Implementation ◽  
Bayesian Techniques ◽  
Systematic Methodology ◽  
Important Input ◽  
Input Variables ◽  
Selection Of

In this paper, emphasis is put on the design of a neural network to model the direct solar irradiance. Since unfortunately a neural network (NN) is not a statistician in-a-box, building a NN for a particular problem is a non trivial task. As a consequence, we argue that in order to properly model the direct solar irradiance, a systematic methodology must be employed. For this purpose, we propose a two-step approach to building the NN model. The first step deals with a probabilistic interpretation of the NN learning by using Bayesian techniques. The Bayesian approach to modelling offers significant advantages over the classical NN learning process. Among others, one can cite a) automatic complexity control of the NN using all the available data b) selection of the most important input variables. The second step consists in using a new sensitivity analysis-based pruning method in order to infer the optimal NN structure. We show that the combination of the two approaches makes the practical implementation of the Bayesian techniques more reliable.

scholarly journals A Method for Detecting the Randomness of Barkhausen Noise in a Material Fatigue Test Using Sensitivity and Uncertainty Analysis

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5383
Author(s):  
Yuting Hou ◽  
Xiang Li ◽  
Yang Zheng ◽  
Jinjie Zhou ◽  
Jidong Tan ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Probability Distribution ◽  
Confidence Interval ◽  
Quantitative Description ◽  
Superior Performance ◽  
Internal Stresses ◽  
Barkhausen Noise ◽  
Great Effort ◽  
Parameter Uncertainties ◽  
Leibler Divergence

The magnetic Barkhausen noise (MBN) signal provides interesting clues about the evolution of microstructure of the magnetic material (internal stresses, level of degradation, etc.). This makes it widely used in non-destructive evaluation of ferromagnetic materials. Although researchers have made great effort to explore the intrinsic random characteristics and stable features of MBN signals, they have failed to provide a deterministic definition of the stochastic quality of the MBN signals. Because many features are not reproducible, there is no quantitative description for the stochastic nature of MBN, and no uniform standards to evaluate performance of features. We aim to make further study on the stochastic characteristics of MBN signal and transform it into the quantification of signal uncertainty and sensitivity, to solve the above problems for fatigue state prediction. In the case of parameter uncertainty in the prediction model, a prior approximation method was proposed. Thus, there are two distinct sources of uncertainty: feature(observation) uncertainty and model uncertainty were discussed. We define feature uncertainty from the perspective of a probability distribution using a confidence interval sensitivity analysis, and uniformly quantize and re-parameterize the feature matrix from the feature probability distribution space. We also incorporate informed priors into the estimation process by optimizing the Kullback–Leibler divergence between prior and posterior distribution, approximating the prior to the posterior. Thus, in an insufficient data situation, informed priors can improve prediction accuracy. Experiments prove that our proposed confidence interval sensitivity analysis to capture feature uncertainty has the potential to determine the instability in MBN signals quantitatively and reduce the dispersion of features, so that all features can produce positive additive effects. The false prediction rate can be reduced to almost 0. The proposed priors can not only measure model parameter uncertainties but also show superior performance similar to that of maximum likelihood estimation (MLE). The results also show that improvements in parameter uncertainties cannot be directly propagated to improve prediction uncertainties.

Application of VISSIM in Public Transit Facilities Analysis and Evaluation

2013 ◽  
Vol 361-363 ◽  
pp. 2293-2296 ◽  
Author(s):  
Hong Zhou Cai ◽  
Shou Feng Ma ◽  
Li Wei
Keyword(s):  
Public Transit ◽  
Urban Transportation ◽  
Mutual Interference ◽  
Simulation Software ◽  
Level Of Service ◽  
Microscopic Simulation ◽  
Bus Priority ◽  
Left Turn ◽  
Analysis And Evaluation ◽  
Tianjin City

The level of service and efficiency of public transit facilities affect the functions of urban transportation. VISSIM as a microscopic simulation software is conducted to model the operation processes of public transit facilities in the Huayuan intersection located in Tianjin city of China. Three problems are found in this study as following: seriously mutual interference between buses and cars nearby the transit facilities, deficient capacity of left-turn lanes, serious delay at the intersection including buses and cars. Some improved measures are proposed to solve these problems in the research such as changing the location of bus stops, placing bus priority signs and adding lanes. These measures compose three improved schemes. The effects of these schemes are compared from travel times, delay, queue length and bus waiting time. The simulating results show that these schemes can effectively increase the speed of buses and reduce their delay at the intersection.

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