Evaluating the Operational Efficiency of Two Versions of Super Diverging Diamond Interchange Design: A Case Study in Denver, Colorado

2021 ◽  
pp. 036119812110372
Author(s):  
Muhammad Tahmidul Haq ◽  
Amirarsalan Mehrara Molan ◽  
Khaled Ksaibati
Keyword(s):  
Research Effort ◽  
Traffic Signals ◽  
Operational Efficiency ◽  
Traffic Demand ◽  
Operational Analysis ◽  
Signal Coordination ◽  
Traffic Volumes ◽  
Microsimulation Models ◽  
Better Than

This paper aims to advance the current research on the new super diverging diamond interchange (super DDI) design by evaluating the operational efficiency using real-world locations. As part of a comprehensive research effort on improving the performance of failing service interchanges in the mountain-plains region, the study identified three interchanges (Interstate 225 and Mississippi Avenue, Interstate 25 and 120th Avenue, and Interstate 25 and Hampden Avenue) at Denver, Colorado as the potential candidates to model for future retrofit. Four interchange designs (i.e., existing CDI [conventional diamond interchange], DDI, super DDI-1, and super DDI-2) were tested in this study. The operational analysis was conducted using VISSIM and Synchro. Several microsimulation models (120 scenarios with 600 runs in total) were created with three peak hours (a.m., noon, and p.m.) for existing (the year 2020) and projected (the year 2030) traffic volumes. The study considered two simulation networks: (1) when no adjacent traffic signal exists, to determine how the four interchange designs would perform if there were no adjacent signals or they were far away from the interchange; and (2) when there are two adjacent traffic signals, to evaluate the performance of the four interchanges in a bigger corridor with signal coordination needed. An important finding is that super DDI designs outperformed DDI with adjacent signals and higher traffic demand, while DDI performed similarly to or sometimes insignificantly better than super DDI if no adjacent intersections were located in the vicinity and if the demand was lower than the DDI’s capacity.

Traffic Platoon Dispersion Modeling on Arterial Streets

1996 ◽  
Vol 1566 (1) ◽  
pp. 49-53 ◽  
Author(s):  
Abdelaziz Manar ◽  
Karsten G. Baass
Keyword(s):  
Simulation Models ◽  
Traffic Signals ◽  
External Friction ◽  
Dispersion Modeling ◽  
Arterial Streets ◽  
Signal Coordination ◽  
Traffic Volumes ◽  
Platoon Dispersion ◽  
The City ◽  
Maximal Capacity

Platoon dispersion is a key element in traffic simulation models designed to measure arrivals at traffic signals. One of the most popular models is contained in the TRANSYT program. In this program, dispersion is defined by the platoon dispersion factor, which is given for three types of conditions in relation to external friction. This study demonstrates that platoon dispersion depends not only on external friction but also on internal friction between vehicles in the platoon. As volumes and densities increase, platoon dispersion increases up to a maximum, which is attained at half the capacity. As volumes and densities increase further, dispersion decreases and reaches a minimum value at volumes around maximal capacity. Experimental analysis on eight arterial sites in the city of Montreal (Quebec, Canada) has confirmed this relationship between dispersion and traffic volumes. Mathematical models (having a parabolic shape) relating platoon dispersion to internal and external friction were developed for three different categories of arterial streets representing low, moderate, and heavy friction levels. These models could be introduced into signal coordination programs and could contribute to a better simulation of arriving platoons at intersections as volumes change in relation to time.

scholarly journals Possibility of Microsimulation Models Calibration – Case Study in the City of Split

1970 ◽  
Vol 24 (3) ◽  
pp. 231-241
Author(s):  
Dražen Cvitanić ◽  
Deana Breški ◽  
Ivan Lovrić
Keyword(s):  
Dynamic Traffic Assignment ◽  
Simulation Models ◽  
Traffic Signals ◽  
Flow Speed ◽  
Good Prediction ◽  
Free Flow Speed ◽  
Microsimulation Models ◽  
The City ◽  
Made In

The paper presents a comparison of the possibility and complexity of the calibration process of two microsimulation models. The first model CORSIM is simple for use while the second named S-Paramics is more complex software. For research purposes, a model of street network with defined geometry (number, width and purpose of lanes) has been made. The volume and distribution of traffic as well as the data about traffic signals were input in the models. Numerous simulations were performed, first with the default parameters of models, and then with the calibrated parameters. Both programs have resulted in very good prediction of the intersection capacity and discharge volumes. However, for the calibration of speed more time and effort have been made in S-Paramics in which the average speed may be higher than the defined free-flow speed. This can present a problem in determining the level of service and comparing the S-Paramics results with other simulation models and analytical method results. On the other hand S-Paramics has greater capabilities than CORSIM (roundabouts modelling, dynamic traffic assignment, opportunity to interact with traffic signals...). Thus, for each specific task, one should carefully choose an appropriate program which would result in necessary and reliable output data with minimum effort and time consumed.

scholarly journals Traffic Signal Coordination for Tramlines with Passive Priority Strategy

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Yun Bai ◽  
Jiajie Li ◽  
Tang Li ◽  
Lingling Yang ◽  
Chenxi Lyu
Keyword(s):  
Dwell Time ◽  
Coordinated Control ◽  
Traffic Signals ◽  
Travel Speed ◽  
Simulation Software ◽  
Traffic Signal ◽  
Model Case ◽  
Signal Coordination ◽  
Proposed Model ◽  
Traffic Volumes

Prioritizing traffic signals for trams crossing intersections without stops can increase the service punctuality and travel speed of trams, but it may also increase the delays of other vehicles at intersections. This paper presents a model on coordinated control of traffic signals among successive intersections along the tramline, taking into account driving characteristics of trams and vehicles. The objective is maximizing the valid bandwidth of vehicle green wave to reduce vehicle delays, while the trams cross intersections without stops. Linear Interactive and General Optimizer (LINGO) is applied to solve the proposed model and VISSIM simulation software is adopted to assess the solutions attained by the proposed model and the previous TRAMBAND model. Case studies show that the solutions given by the proposed model facilitate trams to go through all intersections along the tramline without stops. In comparison with the TRAMBAND model, the proposed model reduces tram delay by 13.14 s/pcu and increases the throughput of vehicles at intersections by 4.45% and reduces vehicle delays by 2.22%. Extensive simulations have verified that the performance of the proposed model is stable under different tram headways, dwell time, and traffic volumes. It is also found that the tram headway must be multiple of traffic signal cycle time to completely realize green wave control of all trams at all intersections along the tramline.

Municipal wastewater treatment with pond–constructed wetland system: a case study

2005 ◽  
Vol 51 (12) ◽  
pp. 325-329 ◽  
Author(s):  
X. Wang ◽  
X. Bai ◽  
J. Qiu ◽  
B. Wang
Keyword(s):  
Constructed Wetland ◽  
Municipal Wastewater ◽  
Municipal Wastewater Treatment ◽  
Oxidation Pond ◽  
System A ◽  
Treated Effluent ◽  
Wetland System ◽  
Oxidation Ponds ◽  
Better Than

The performance of a pond–constructed wetland system in the treatment of municipal wastewater in Kiaochow city was studied; and comparison with oxidation ponds system was conducted. In the post-constructed wetland, the removal of COD, TN and TP is 24%, 58.5% and 24.8% respectively. The treated effluent from the constructed wetland can meet the Chinese National Agricultural and Irrigation Standard. The comparison between pond–constructed wetland system and oxidation pond system shows that total nitrogen removal in a constructed wetland is better than that in an oxidation pond and the TP removal is inferior. A possible reason is the low dissolved oxygen concentration in the wetland. Constructed wetlands can restrain the growth of algae effectively, and can produce obvious ecological and economical benefits.

Estimating Pedestrian Impact on Coordination of Urban Corridors

2019 ◽  
Vol 2673 (7) ◽  
pp. 265-280 ◽  
Author(s):  
Sharmin-E-Shams Chowdhury ◽  
Aleksandar Stevanovic ◽  
Nikola Mitrovic
Keyword(s):  
Cycle Length ◽  
Network Performance ◽  
Traffic Signals ◽  
High Fidelity ◽  
Vehicular Traffic ◽  
Traffic Demand ◽  
Advantages And Disadvantages ◽  
Street Traffic ◽  
Pedestrian Impact ◽  
Signal Operations

Pedestrian walk timings at most U.S. traffic signals are run in concurrence with relevant signal phases for vehicular traffic. This usually means that signal operations coordinated for the major street can be interrupted by a pedestrian call. Such an interruption may in practice last for a few minutes, thus causing increased delays and stops for major traffic flows. An alternative to this design is to increase the cycle length and embed pedestrian timings within the ring-barrier structure of the prevailing coordination plan. Both approaches have advantages and disadvantages. A fresh approach offered by this study is a comprehensive experimental design and holistic performance evaluation perspectives. The study examines the two abovementioned treatments of pedestrian timings for a small corridor of five intersections in Utah. The experiments have been done in a high-fidelity microsimulation environment with the Software-in-the-Loop version of the field controller (Econolite ASC/3). Findings show that either approach works well for very low traffic demands. When the traffic demand increases findings cannot be generalized as they differ for major coordinated movements versus overall network performance. While major-street traffic prefers no interruption of the coordinated operations, the overall network performance is better in the other case. This can be explained by the fact that avoiding interruptions is usually achieved at the expense of longer cycle length, which increases delay for everyone in the network.

Improvement of environmental health and hygiene practices - case study in the Northern Province

2001 ◽  
Vol 44 (6) ◽  
pp. 109-117 ◽  
Author(s):  
M. A. Mathegana ◽  
L. K. Chauke ◽  
F. A.O. Otieno
Keyword(s):  
South Africa ◽  
Environmental Health ◽  
Northern Province ◽  
Active Involvement ◽  
Sustainable Improvement ◽  
Hygiene Practices ◽  
Proper Training ◽  
The Government ◽  
Better Than

The primary purpose of an improved water supply and sanitation is the achievement of acceptable health and hygiene standards as well as the sustainable improvement of the environment. Many governments recognize this and so they budget for large sums of money to improve these services to the communities. The purpose of this study was to investigate the different gaps in environmental health and hygiene practices with the aim of suggesting a strategy of improving this in the Northern Province of South Africa. To do this, 231 households and 30 schools were surveyed. Workshops and visits to different government departments were also used. This paper reports the results from this study which indicate that the situation in schools was not any better than that in households, with more than 90% of the villages still dependent on the unimproved pit latrines and 56,6% relying on standpipes which were (70% of the time) non-operational. The main problems identified seem to those associated with implementation and maintenance. The study concludes that with proper training of the water committees and their active involvement with the government and NGOs, environmental health and hygiene problems can be minimized or eliminated.

Introducing Problem-based Learning to Special Needs Dentistry—A Case Study

2002 ◽  
Vol os9 (1) ◽  
pp. 9-13 ◽  
Author(s):  
Raman Bedi ◽  
Jackie A Champion ◽  
Roger Davies
Keyword(s):  
Special Needs ◽  
Problem Based Learning ◽  
Chi Square ◽  
Training And Education ◽  
Mixed Response ◽  
Conventional Teaching ◽  
The Subject ◽  
Better Than ◽  
Made In

Introduction In order to promote training and education in special-needs dentistry an attempt was made to introduce problem-based learning (PBL) as a method of postgraduate dental education. The aim of this paper was to review the principles of PBL and report on a case study using this methodology. Method The case study was of a PBL session, on the subject of ‘problems of obtaining appropriate dental care for people with epilepsy’, undertaken at a national conference. Delegates were asked to complete a pre- and post-session questionnaire on PBL and their attitudes to the session. Results The session received a mixed response. Only 33 (35%) thought the session was valuable and only 20 (31%) thought it was better than conventional teaching methods and yet over half (55%) said they would like to attend more PBL in special-needs dentistry. Professionals complementary to dentistry were more likely to find the PBL session of value and to prefer the method to a more conventional format than dentists were (chi-square=5.5, df=1, p<0.05 and chi-square=5.9, df=1, p<0.05 respectively). Conclusion Valuable feedback was received from delegates. This will enable improvements to be made in future courses so that the effectiveness of PBL can be optimised.

The Plan Guidelines for Villages under the Background of Nomadic Settlement — A Case Study of Luqu County in Gannan Tibetan Autonomous Prefecture

2012 ◽  
Vol 518-523 ◽  
pp. 5886-5893
Author(s):  
Lu Cang Wang ◽  
Wei Li ◽  
Jing Gao
Keyword(s):  
Economic Development ◽  
Yellow River ◽  
Functional Area ◽  
Spatial Displacement ◽  
Community Based ◽  
Construction Tasks ◽  
The Village ◽  
Pastoral Farming ◽  
Better Than

“The Project of Nomadic Settlement” is one of the major construction tasks for “Gannan Important Water Supply Ecological Functional Area of Yellow River”. Because of the distribution of population and settlements have obvious discreteness and wavering in alpine pasture, it is necessary to plan and guide agricultural and grazing villages during the process of the construction of nomadic settlements, spatial displacement and integration of population and settlement. The nomadic habitation mode in Luqu county undergoes four stages. At present, it adopts four settlement modes, that is, centralized settlement mode in the county town, settlement mode in the village, settlement along the highway mode and dispersed settlement mode, involving a total of 2,645households,13,783people and be arranged in 21 settlements. The paper adopts 14 indicators related conditions of economic development, social development conditions, geographic conditions, measures the overall strength of 24 administrative villages in Luqu, the whole villages are divided into four grade. The results show that the suburban villages are better than the surrounding villages and towns, pure pastoral farming are better than farming-pastoral villages. Accordingly, 24 villages are divided into four types—community-based villages, developing villages, controlling villages, and revoking-merging villages. Finally, it also proposes the path on village plan guidelines.

Improving Operational Efficiency Using Automated Time Analysis for Multi-Well Pad Fracturing

2021 ◽  
Author(s):  
Fahd Siddiqui ◽  
Mohammadreza Kamyab ◽  
Michael Lowder
Keyword(s):  
Real Time ◽  
Operational Efficiency ◽  
Permian Basin ◽  
Potential Cost ◽  
Time Period ◽  
Cloud Server ◽  
The Us ◽  
Single Well ◽  
Complete Automation

Abstract The economic success of unconventional reservoirs relies on driving down completion costs. Manually measuring the operational efficiency for a multi-well pad can be error-prone and time-prohibitive. Complete automation of this analysis can provide an effortless real-time insight to completion engineers. This study presents a real-time method for measuring the time spent on each completion activity, thereby enabling the identification and potential cost reduction avenues. Two data acquisition boxes are utilized at the completion site to transmit both the fracturing and wireline data in real-time to a cloud server. A data processing algorithm is described to determine the start and end of these two operations for each stage of every well on the pad. The described method then determines other activity intervals (fracturing swap-over, wireline swap-over, and waiting on offset wells) based on the relationship between the fracturing and wireline segments of all the wells. The processed data results can be viewed in real-time on mobile or computers connected to the cloud. Viewing the full operational time log in real-time helps engineers analyze the whole operation and determine key performance indicators (KPIs) such as the number of fractured stages per day, pumping percentage, average fracture, and wireline swap-over durations for a given time period. In addition, the performance of the day and night crews can be evaluated. By plotting a comparison of KPIs for wireline and fracturing times, trends can be readily identified for improving operational efficiency. Practices from best-performing stages can be adopted to reduce non-pumping times. This helps operators save time and money to optimize for more efficient operations. As the number of wells increases, the complexity of manual generation of time-log increases. The presented method can handle multi-well fracturing and wireline operations without such difficulty and in real-time. A case study is also presented, where an operator in the US Permian basin used this method in real-time to view and optimize zipper operations. Analysis indicated that the time spent on the swap over activities could be reduced. This operator set a realistic goal of reducing 10 minutes per swap-over interval. Within one pad, the goal was reached utilizing this method, resulting in reducing 15 hours from the total pad time. The presented method provides an automated overview of fracturing operations. Based on the analysis, timely decisions can be made to reduce operational costs. Moreover, because this method is automated, it is not limited to single well operations but can handle multi-well pad completion designs that are commonplace in unconventionals.

Sign in / Sign up

Export Citation Format

Share Document