scholarly journals On the Urban Link Fundamental Diagram Based on Velocity-Weighted Flow and Queue Length

Symmetry ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1852
Author(s):  
Hansong Yu ◽  
Junwei Kong ◽  
Ye Ren ◽  
Chenkun Yin
Keyword(s):  
Traffic Flow ◽  
Cycle Time ◽  
Queue Length ◽  
Great Influence ◽  
Simulation Software ◽  
Simulation Studies ◽  
Fundamental Diagram ◽  
Traffic Condition ◽  
The Relationship ◽  
Symmetric Shape

For uninterrupted traffic flow, it is well-known that the fundamental diagram (FD) describes the relationship between traffic flow and density under steady state. To study the characteristics of interrupted traffic flow on a signalized link, a link fundamental diagram (LFD) for urban roads is proposed in this paper. First, a new variable, which synthesizes traffic flow with the speed of each vehicle, is defined. Then, the link fundamental diagram is obtained by drawing a scatter-plot of the velocity-weighted flow versus queue length, which takes on a unimodal curve with an approximately symmetric shape. Finally, simulation studies are conducted by modeling an urban link based on the traffic simulation software VISSIM. Compared with the traditional fundamental diagram, the proposed link fundamental diagram is more intuitive for showing the relationship between traffic condition and queue length. The impacts of the cycle time, green time, and split on the proposed link fundamental diagram are studied. Simulation results show that the shape of the link fundamental diagram fundamentally is determined by the split. The critical point is correlated to split values, and the green time exerts a great influence on both the velocity-weighted flow and the critical queue length. The cycle time has little effect on the critical queue length but has a great influence on the velocity-weighted flow.

scholarly journals Evaluating Impacts of Overloaded Heavy Vehicles on Freeway Traffic Condition by a Novel Multi-Class Traffic Flow Model

2018 ◽  
Vol 10 (12) ◽  
pp. 4694 ◽  
Author(s):  
Xiang Wang ◽  
Po Zhao ◽  
Yanyun Tao
Keyword(s):  
Traffic Flow ◽  
Flow Model ◽  
Management Strategies ◽  
Maximum Speed ◽  
Heavy Vehicles ◽  
Fundamental Diagram ◽  
Traffic Condition ◽  
Traffic Flow Model ◽  
Traffic Conditions ◽  
The Impact

Overloaded heavy vehicles (HVs) have significant negative impacts on traffic conditions due to their inferior driving performance. Highway authorities need to understand the impact of overloaded HVs to assess traffic conditions and set management strategies. We propose a multi-class traffic flow model based on Smulders fundamental diagram to analyze the influence of overloaded HVs on traffic conditions. The relationship between the overloading ratio and maximum speed is established by freeway toll collection data for different types of HVs. Dynamic passenger car equivalent factors are introduced to represent the various impacts of overloaded HVs in different traffic flow patterns. The model is solved analytically and discussed in detail in the appendices. The model validation results show that the proposed model can represent traffic conditions more accurately with consideration for overloaded HVs. The scenario tests indicate that the increase of overloaded HVs leads to both a higher congestion level and longer duration.

scholarly journals Analisis Kinerja Persimpangan Jalan Laswi dengan Jalan Gatot Subroto, Kota Bandung Menggunakan PTV VISSIM 9.0. (Hal. 74-85)

2019 ◽  
Vol 5 (3) ◽  
pp. 74
Author(s):  
Fadila Dwithami Ulfah ◽  
Oka Purwanti
Keyword(s):  
Performance Analysis ◽  
Traffic Flow ◽  
Cycle Time ◽  
Queue Length ◽  
Shopping Centers ◽  
Residential Areas ◽  
Signal Phase ◽  
Cycle Times

ABSTRAKPersimpangan Jalan Laswi – Jalan Gatot Subroto merupakan salah satu persimpangan di Kota Bandung yang menghubungkan daerah perkantoran, pendidikan, dan pusat perbelanjaan dengan daerah permukiman. Permasalahan yang terjadi yaitu, besarnya volume arus lalu lintas sehingga menyebabkan panjangnya antrian, dan lamanya tundaan. Tujuan peneletian ini adalah menganalisis kinerja persimpangan eksisting, dan menganalisis pengaruh optimalisasi waktu siklus terhadap kinerja persimpangan tersebut. Berdasarkan kondisi eksisting persimpangan, kinerja persimpangan sudah tidak bisa dianalisis menggunakan MKJI 1997 karena diperoleh  adalah 1,2036 atau simpang sudah lewat jenuh, sehingga analisis dilanjutkan menggunakan PTV VISSIM 9.0. Hasil analisis kinerja persimpangan kondisi eksisting, dan optimalisasi waktu siklus (skenario pangaturan fase sinyal B3) yaitu, penurunan panjang antrian dan tundaan rata-rata simpang sebesar 9,70%, dan penurunan tundaan rata-rata simpang sebesar 19,57%.Kata kunci: persimpangan, panjang antrian, tundaan, lewat jenuh, optimalisasi waktu siklus ABSTRACTIntersection of Laswi road with Gatot Subroto road is one of the intersections in Bandung City that connects offices areas, education areas, and shopping centers areas with residential areas. Problems that occur is the amount of traffic flow that causes the length of the queue, and the length of delay. The purpose of this research was to analyze the performance of the existing intersection, and analyze the optimization of cycle times against the performance of these intersections. Based on existing intersection conditions, intersection performance cannot be analyzed using MKJI 1997 because   adalah 1.2036 or the intersection is over saturated, so the analysis continued using PTV VISSIM 9.0. The results of the intersection performance analysis of existing conditions, and optimization of cycle time (B3 signal phase settings scenario) that is, a decrease in the queue length of the average intersection by 9.70%, and a delay decrease of the intersection average by 19.57%.Keywords: intersection, queue length, delay, over saturated, optimization of cycle time

Evaluation Analysis and Optimization Design of Urban Road Traffic Condition Based on VISSIM

2011 ◽  
Vol 97-98 ◽  
pp. 531-534
Author(s):  
Xin Qiu ◽  
An Xia Zheng ◽  
Ying Zhu ◽  
Bin Xu
Keyword(s):  
Traffic Flow ◽  
Optimization Design ◽  
Road Traffic ◽  
Flow Characteristics ◽  
Simulation Software ◽  
Traffic Condition ◽  
Urban Road ◽  
The Road ◽  
Road Congestion

Based on the survey of the traffic flow characteristics in the intersection, combined with the traffic flow basic principle and the existing research results at home and abroad, the road congestion condition is evaluated by determining the microcosmic evaluation index coefficient by VISSIM microcosmic simulation software. Then, the reasonable measures are put forward to improve urban road congestion condition. The analysis shows that the residents’ trip efficiency is improved and the quality of the urban road traffic condition is ameliorated.

Field Theory for Some Traffic Phenomena and Fundamental Diagram

2021 ◽  
pp. 036119812110064
Author(s):  
Daiheng Ni
Keyword(s):  
Field Theory ◽  
Traffic Flow ◽  
Causal Effect ◽  
Microscopic Approach ◽  
Fundamental Diagram ◽  
Longitudinal Control ◽  
Effect Analysis ◽  
Vehicle Trajectories ◽  
Vehicle Motion ◽  
Cross Reference

A fundamental diagram consists of a scatter of traffic flow data sampled at a specific location and aggregated from vehicle trajectories. These trajectories, if presented equivalently, constitute a microscopic version of the (conventional) fundamental diagram. The cross-reference between vehicle trajectories and the microscopic fundamental diagram provides details of vehicle motion dynamics which allow causal-effect analysis on some traffic phenomena and further reveal the microscopic basis of the conventional fundamental diagram. This observation inspires theoretical modeling by a microscopic approach to address traffic phenomena and the conventional fundamental diagram. Derived from the field theory of traffic flow, the longitudinal control model is capable of serving the purpose without the modifications or exceptions used by other approaches.

Design and simulation research of the double-spin folding mechanism based on a suspended missile

2021 ◽  
pp. 154851292110231
Author(s):  
ZH Yuan ◽  
SY Guo ◽  
SN Zhang ◽  
JQ Zhao ◽  
WJ Lu ◽  
...  
Keyword(s):  
High Reliability ◽  
Lift Coefficient ◽  
Great Influence ◽  
Reference Value ◽  
Aerodynamic Characteristics ◽  
Simulation Software ◽  
Fluid Simulation ◽  
Simulation Research ◽  
Double Spin ◽  
Locking Mechanism

Based on the suspension of a missile using folding rotary wings and airbags, in order to improve the basic parameters and motion characteristics of the rotor during the unfolding process and analyze the aerodynamic characteristics of the entire device in the suspension state, after proposing a scheme of double-spin mechanism, the main folding and unfolding mechanism, initial driving device, rotating driving device, and locking mechanism were designed, and the simulation research is studied by the Automatic Dynamic Analysis of Mechanical System and Ansys Fluent Fluid Simulation software, respectively. The results show that the rotation rate was controlled at 41.8 mm/s, the various motion parameters are reasonable, and the operation process is relatively smooth, with high reliability. The speed and pressure value at the tip of the rotor are higher and the aerodynamic disturbance is obvious, which has a great influence on the aerodynamic performance. The speed and pressure distribution of the surrounding flow field is stable, the lift provided is 46 N, and the lift coefficient is 0.55, which can ensure the long-time suspension state of the missile. This paper puts forward a valuable design idea and has practical reference value for the research of the suspended missile.

scholarly journals The use of simulation modelling for determining the capacity of railway lines in the Czech conditions

2020 ◽  
Vol 10 (1) ◽  
pp. 224-231
Author(s):  
Erik Tischer ◽  
Petr Nachtigall ◽  
Jaromír Široký
Keyword(s):  
Czech Republic ◽  
Traffic Flow ◽  
Software Tool ◽  
Simulation Modelling ◽  
Energy Performance ◽  
Simulation Software ◽  
The Czech Republic ◽  
Railway Line ◽  
Specialized Software ◽  
Railway Infrastructure

AbstractSimulation modelling is one way to determine the capacity of railway lines. The specialized software tool OpenTrack was used for simulation. The aim of this paper was to find out whether the OpenTrack simulation software can be used for the calculation of headway, and to compare the results with the methodology of the Railway Infrastructure Administration (SŽDC). Using the software tool, a detailed transport network model can be created including all its important characteristics. The simulation follows the movements and behaviour of trains with predefined parameters on the modelled railway line. OpenTrack allows for monitoring a range of parameters including not only train delays, train conflicts and train traffic flow, but also for instance train energy performance and headways. During the first stage of work with OpenTrack, a simulation model was created, not reflecting any existing infrastructure but including parameters typical of railway lines in the Czech Republic, such as the configuration of gridirons, length of station tracks, size of block sections, etc. This model was subsequently used for the simulation of type train set journeys, and a headway calculator was used for the calculation of headway values. These values were compared with the methodology used by the Railway Infrastructure Administration. The paper is concluded by the comparison of the above mentioned approaches.

scholarly journals Simple empirical method for estimating lava-effusion rate using nighttime Himawari-8 1.6-µm infrared images

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Takayuki Kaneko ◽  
Atsushi Yasuda ◽  
Toshitsugu Fujii
Keyword(s):  
Lava Flow ◽  
Estimation Method ◽  
Simulation Software ◽  
Spectral Radiance ◽  
Effusion Rate ◽  
Actual Distribution ◽  
High Positive Correlation ◽  
Low Viscosity ◽  
Lava Effusion ◽  
The Relationship

AbstractThe effusion rate of lava is one of the most important eruption parameters, as it is closely related to the migration process of magma underground and on the surface, such as changes in lava flow direction or formation of new effusing vents. Establishment of a continuous and rapid estimation method has been an issue in volcano research as well as disaster prevention planning. For effusive eruptions of low-viscosity lava, we examined the relationship between the nighttime spectral radiance in the 1.6-µm band of the Himawari-8 satellite (R1.6Mx: the pixel value showing the maximum radiance in the heat source area) and the effusion rate using data from the 2017 Nishinoshima activity. Our analysis confirmed that there was a high positive correlation between these two parameters. Based on the linear-regression equation obtained here (Y = 0.47X, where Y is an effusion rate of 106 m3 day−1 and X is an R1.6Mx of 106 W m−2 sr−1 m−1), we can estimate the lava-effusion rate from the observation data of Himawari-8 via a simple calculation. Data from the 2015 Raung activity—an effusive eruption of low-viscosity lava—were arranged along the extension of this regression line, which suggests that the relationship is applicable up to a level of ~ 2 × 106 m3 day−1. We applied this method to the December 2019 Nishinoshima activity and obtained an effusion rate of 0.50 × 106 m3 day−1 for the initial stage. We also calculated the effusion rate for the same period based on a topographic method, and verified that the obtained value, 0.48 × 106 m3 day−1, agreed with the estimation using the Himawari-8 data. Further, for Nishinoshima, we simulated the extent of hazard areas from the initial lava flow and compared cases using the effusion rate obtained here and the value corresponding to the average effusion rate for the 2013–2015 eruptions. The former distribution was close to the actual distribution, while the latter was much smaller. By combining this effusion-rate estimation method with real-time observations by Himawari-8 and lava-flow simulation software, we can build a rapid and precise prediction system for volcano hazard areas.

Sign in / Sign up

Export Citation Format

Share Document