scholarly journals Traffic flow rate on Kigali roads: a case of national roads (RN1 and RN3)

2021 ◽  
Vol 2 (3) ◽  
Author(s):  
Jacqueline Nyirajana ◽  
Akinwale Oladotun Coker ◽  
Folake Olubunmi Akintayo
Keyword(s):  
Traffic Flow ◽  
Flow Rate ◽  
Critical Density ◽  
Maximum Flow ◽  
Carbon Dioxide Production ◽  
Flow State ◽  
Fundamental Diagram ◽  
Essential Facility ◽  
Time Scheduling ◽  
Road Planning

Traffic flow study plays a key important in various functionalities of cities all over the world. The study of traffic flow is also viewed as an essential facility of the country when it wants to establish traffic operations patterns in the progress of road planning. Blockages are accountable for a sequence of harmful effects such as loss of time, scheduling difficulties, carbon dioxide production, and risks of accidents as well as external expenses. Besides, inadequate transportation facilities and increased traffic volume hamper urban development, especially in developing nations. The objective of the study was to assess the traffic flow state in two selected national roads of Kigali city. The traffic data were collected from 5 am to 8 pm on two National Roads (RN1 and RN3).  The relationship between density and flow rate was analyzed using the fundamental diagram of traffic flow. It was found that the peak hours were from 6 am to 8 am and 5 pm to 8 pm. The highest number of vehicles counted were motorcycles due to shortcuts taken to reduce travel time. The results on RN3 revealed a proportion increase of traffic flow and density in the free-flow regime from 0 to maximum flow of 3346.6 veh/h correspondent to a critical density of 114.9 veh/km. However, in the congested zone regime, there was a decrease in traffic flow and an increase in density. It was found that the curve of flow versus density tended to increase on-road RN1. This study proposed the promotion of public transport and e-commerce as strategies to mitigate the congestion. Also, further research may be carried out on all roads of Kigali city, to provide the level of congestion useful for traffic deviation accordingly.

A NEW CELLULAR AUTOMATON MODEL FOR TRAFFIC FLOW WITH DIFFERENT PROBABILITY FOR DRIVERS

2007 ◽  
Vol 18 (05) ◽  
pp. 773-782 ◽  
Author(s):  
H. B. ZHU ◽  
H. X. GE ◽  
S. Q. DAI
Keyword(s):  
Cellular Automaton ◽  
Traffic Flow ◽  
Metastable State ◽  
Maximum Flow ◽  
Traffic Model ◽  
Fundamental Diagram ◽  
Density Dependent ◽  
Spontaneous Formation ◽  
Traffic Jams ◽  
Ca Model

Based on the Nagel–Schreckenberg (NaSch) model of traffic flow, a new cellular automaton (CA) traffic model is proposed to simulate microscopic traffic flow. The probability p is a variable which contains a randomly selected term for each individual driver and a density-dependent term which is the same for all drivers. When the rational probability p is obtained, the larger value of maximum flow which is close to the observed data can be reached compared with that obtained from the NaSch model. The fundamental diagram obtained by simulation shows the ability of this modified CA model to capture the essential features of traffic flow, e.g., the spontaneous formation of traffic jams and appearance of the metastable state. These indicate that the presented model is more reasonable and realistic.

Effect of Multi-Slowdown Sections on Traffic Flow

2012 ◽  
Vol 253-255 ◽  
pp. 1619-1622
Author(s):  
Yan Hong Fan ◽  
Hua Kuang ◽  
Guo Xin Zhang ◽  
Ling Jiang Kong ◽  
Xing Li Li
Keyword(s):  
Energy Consumption ◽  
Traffic Flow ◽  
Maximum Flow ◽  
Underlying Mechanism ◽  
Speed Limit ◽  
Fundamental Diagram ◽  
Mean Velocity ◽  
Traffic System ◽  
Flow Phase ◽  
Multi Phase

Based on the NS model, an extended cellular automaton model is proposed to simulate complex characteristics and energy consumption of traffic flow with some slowdown sections on a highway by considering the number, speed limit and distribution of slowdown sections. The simulation results show that the present model can exhibit a multi-phase coexistence phenomenon, i.e., the freely moving phase, the maximum flow phase and the jamming phase coexist in traffic system. The fundamental diagram shows that the number of slowdown section has no influence on the mean velocity and flow. However, energy consumption increases with increase of the number of slowdown section at low density. In addition, it can be found that the speed limit and distribution of different slowdown sections have an important effect on traffic flow and energy consumption, and the underlying mechanism is also analyzed.

THE TRAFFIC BOTTLENECK EFFECTS CAUSED BY THE LANE CLOSING IN THE CELLULAR AUTOMATA MODEL

2003 ◽  
Vol 14 (10) ◽  
pp. 1295-1303 ◽  
Author(s):  
BIN JIA ◽  
RUI JIANG ◽  
QING-SONG WU
Keyword(s):  
Cellular Automata ◽  
Traffic Flow ◽  
Flow Rate ◽  
Flow Model ◽  
Maximum Flow ◽  
Density Inversion ◽  
Cellular Automata Model ◽  
Traffic Flow Model ◽  
Density Distributions ◽  
Inversion Phenomenon

As a kind of bottleneck, the lane closing has seldomly been investigated with cellular automata model. In this paper, we study this issue using the cellular automata traffic flow model. The capacity and the density distribution of this kind of bottleneck are discussed in details. We find that (i) the capacity of the bottleneck is a little smaller than the maximum flow rate of single-lane road; (ii) different regulations may lead to different density distributions of the vehicles upstream of the lane closing. Moreover, the density inversion phenomenon is reported under certain conditions. This enlightens us to propose that the phenomenon of density inversion reported in many publications may be caused by the bottlenecks on the highway.

A new cellular automata traffic flow model considering asynchronous update of vehicle velocity

2020 ◽  
Vol 31 (12) ◽  
pp. 2050167
Author(s):  
Qi-Lang Li ◽  
Rui Jiang ◽  
Zhong-Jun Ding ◽  
Bing-Hong Wang
Keyword(s):  
Cellular Automata ◽  
Traffic Flow ◽  
Flow Model ◽  
Maximum Flow ◽  
Fundamental Diagram ◽  
Time Step ◽  
Traffic Flow Model ◽  
Traffic Jam ◽  
Vehicle Velocity ◽  
Flow Phase

This study examines the cellular automata traffic flow model, which considers the asynchronous update of vehicles’ velocities. Computer simulations are used to identify three typical phases: linear free flow phase, nonlinear moving phase and traffic jam phase. Compared to the original NaSch model, the system of the present model can reach the maximum flow when the vehicle density is higher. The influence of the delay probability and the maximum time step in which drivers intend to keep their current velocity on fundamental diagram is discussed.

Fractal Dimension in Time Series of Expressway Traffic Flow

2013 ◽  
Vol 838-841 ◽  
pp. 2088-2091
Author(s):  
Wei Zhang ◽  
Xin He
Keyword(s):  
Time Series ◽  
Fractal Dimension ◽  
Traffic Flow ◽  
Flow Rate ◽  
Fractal Theory ◽  
Operation Management ◽  
Flow State ◽  
Flow Data ◽  
Input Sample ◽  
Statistical Results

The correlation and Hausdroff dimensions of traffic flow and speed series are analyzed based on the Fractal theory. Using the traffic flow data of four typical expressways in China as input sample, the data statistical results indicates that both synchronized and free flow state are fractal and chaotic. In addition, traffic flow rate and speed time series are determined by different intervals and then G-P arithmetic is applied to estimate their correlation dimensions and the Hausdroff dimension. The results also illustrates that Fractal dimension could by clearly identified, which provides a useful tool for expressway operation management and facilities provision.

scholarly journals Self-Organized Criticality of Traffic Flow: There is Nothing Sweet about the Sweet Spot

2021 ◽  
Author(s):  
Jorge Laval
Keyword(s):  
Traffic Flow ◽  
Initial Conditions ◽  
Critical Density ◽  
Basic Unit ◽  
Power Law Distribution ◽  
Fundamental Diagram ◽  
Brownian Excursion ◽  
Self Organized ◽  
Time Space ◽  
Self Organized Criticality

This paper shows that the kinematic wave model exhibits self-organized criticality when initialized with random initial conditions around the critical density. A direct consequence is that conventional traffic management strategies seeking to maximize the flow may be detrimental as they make the system more unpredictable and more prone to collapse. Other implications for traffic flow in the capacity state are discussed, such as: \item jam sizes obey a power-law distribution with exponents 1/2, implying that both its mean and variance diverge to infinity, and therefore traditional statistical methods fail for prediction and control, \item the tendency to be at the critical state is an intrinsic property of traffic flow driven by our desire to travel at the maximum possible speed, \item traffic flow in the critical region is chaotic in that it is highly sensitive to initial conditions, \item aggregate measures of performance are proportional to the area under a Brownian excursion, and therefore are given by different scalings of the Airy distribution, \item traffic in the time-space diagram forms self-affine fractals where the basic unit is a triangle, in the shape of the fundamental diagram, containing 3 traffic states: voids, capacity and jams. This fractal nature of traffic flow calls for analysis methods currently not used in our field.

scholarly journals Characterizing Critical Transition State for Network Fundamental Diagram

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Rongrong Hong ◽  
Chengchuan An ◽  
Zhenbo Lu ◽  
Jingxin Xia ◽  
Qinghui Nie ◽  
...  
Keyword(s):  
Transition State ◽  
Traffic Flow ◽  
Network Traffic ◽  
Field Data ◽  
Experimental Investigations ◽  
Flow State ◽  
Critical Transition ◽  
Fundamental Diagram ◽  
Clustering Model ◽  
Flow States

Macroscopic Fundamental Diagram (MFD) reveals the relationship between network accumulation and flow at the macroscopic level. The network traffic flow state analysis is a fundamental problem for the MFD-based applications. Theoretical and experimental investigations have provided insights into the dynamics and characters of traffic flow states. Although many empirical studies had been conducted in the field of MFD, few studies were dedicated to investigate the network traffic flow states with field data. This study aims to develop a data-driven method based on time series analysis of MFD state points to characterize critical transition state (CTS) of network traffic flow using field data. The proposed method was tested in a real network of Kunshan City, China. The test results showed that the CTS points can be well captured by the proposed method. The identified CTS points distinguished the traffic states between free-flow state and optimal accumulation state, and the optimal accumulation state was characterized. The day-to-day pattern of CTS points was investigated by the Gaussian Mixture Model-based clustering model. An extended application of real-time identification of CTS points was also discussed. The proposed method is helpful to understand the temporal evolution process of network traffic flow and provides potentials for developing more reliable network traffic flow management strategies, such as optimizing traffic signal plans and developing strategies for congestion tooling.

The Analysis of Traffic Flow State on Foggy Expressway Based on Fuzzy Clustering

ICCTP 2009 ◽  
2009 ◽  
Author(s):  
Jianjun Wang ◽  
Chenfeng Xie ◽  
Zhenwen Chang ◽  
Jingjing Zhang
Keyword(s):  
Traffic Flow ◽  
Fuzzy Clustering ◽  
Flow State

Outcome of Buccal Mucosal Graft Urethroplasty in Long Segment Anterior Urethral Stricture

2020 ◽  
Vol 19 (2) ◽  
pp. 64-68
Author(s):  
Mrinmoy Biswas ◽  
Sudip Das Gupta ◽  
Mohammed Mizanur Rahman ◽  
Sharif Mohammad Wasimuddin
Keyword(s):  
Urethral Stricture ◽  
Flow Rate ◽  
Surgical Outcome ◽  
Simple Technique ◽  
Anterior Segment ◽  
Maximum Flow ◽  
Anastomotic Site ◽  
Buccal Mucosal Graft ◽  
Male Patients

Objective: To assess the success of BMG urethroplasty in long segment anterior urethral stricture. Method: From January 2014 to December 2015, twenty male patients with long anterior segment urethral stricture were managed by BMG urethroplasty. After voiding trial they were followed up at 3 month with Uroflowmetry, RGU & MCU and PVR measurement by USG. Patients were further followed up with Uroflowmetry and PVR at 6 months interval.Successful outcome was defined as normal voiding with a maximum flow rate >15ml /sec and PVR<50 ml with consideration of maximum one attempt of OIU after catheter removal. Results: Mean stricture length was 5.2 cm (range 3-9 cm) and mean follow-up was 15.55 months (range 6-23 months). Only two patients developed stricture at proximal anastomotic site during follow-up. One of them voided normally after single attempt of OIU. Other one required second attempt of OIU and was considered as failure (5%). Conclusion: BMG urethroplasty is a simple technique with good surgical outcome. Bangladesh Journal of Urology, Vol. 19, No. 2, July 2016 p.64-68

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