scholarly journals A Modified Total Crossing Time Model of Bidirectional Pedestrians at Signalized Crosswalks

2017 ◽  
Vol 2017 ◽  
pp. 1-12
Author(s):  
Zhanzhong Wang ◽  
Liying Zhao ◽  
Ningbo Cao ◽  
Yue Lu ◽  
Mingtao Chen
Keyword(s):  
Queue Length ◽  
Arrival Rate ◽  
Wave Theory ◽  
Position Distribution ◽  
Discharge Time ◽  
Time Model ◽  
Maximum Queue Length ◽  
Start Up ◽  
Crossing Time ◽  
Traffic Wave

Since crosswalk width and pedestrian green time directly affect the safety of signalized crosswalks, modeling an exact total crossing time model to estimate those two variables is imperative. The total crossing time needed by a group of pedestrians to cross a signalized crosswalk contains the discharge time and the crossing time. The discharge time depends primarily on the maximum queue length, which is determined by pedestrian arrival rate, red interval, waiting position distribution, and the crosswalk width. Crossing time increases when interactions between bidirectional pedestrian flows become more serious. Thus, quantifying the impacts of the start-up process on the discharge time and the effects of the interactions on the crossing time is a prerequisite for optimizing the design of signalized crosswalks. This paper establishes a modified total crossing time model consisting of modified pedestrian discharge and crossing time. Discharge time is modeled by applying traffic wave theory, and crossing time is modeled based on drag force theory. The proposed models provide guidance for the design of crosswalk width and pedestrian green intervals.

Research on the Vehicles Queuing Based on Traffic Accidents

2014 ◽  
Vol 915-916 ◽  
pp. 464-467 ◽  
Author(s):  
Jun Xiong Qi
Keyword(s):  
Cross Section ◽  
Queue Length ◽  
Traffic Accidents ◽  
Wave Model ◽  
Maximum Queue Length ◽  
Length Increase ◽  
Traffic Wave ◽  
The Relationship ◽  
Relationship Equation

In order to study the vehicles queuing under traffic accidents, we put the traffic wave analogy into fluid wave, and build traffic wave model, getting the relationship equation: vehicles queue length and the actual capacity of cross-section, accidents duration, section of the upstream traffic. According to analyzing the equation, we get: the maximum queue length increase with upstream traffic as category Index, however, inversely proportional to the actual capacity, and it is positively correlated with the duration of the accident.

scholarly journals Testing the star formation scaling relations in the clumps of the North American and Pelican nebulae cloud complex

2020 ◽  
Vol 500 (3) ◽  
pp. 3123-3141
Author(s):  
Swagat R Das ◽  
Jessy Jose ◽  
Manash R Samal ◽  
Shaobo Zhang ◽  
Neelam Panwar
Keyword(s):  
Star Formation ◽  
Surface Density ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Free Fall ◽  
Scaling Relations ◽  
Time Model ◽  
Fall Time ◽  
The North ◽  
Crossing Time

ABSTRACT The processes that regulate star formation within molecular clouds are still not well understood. Various star formation scaling relations have been proposed as an explanation, one of which is to formulate a relation between the star formation rate surface density $\rm \Sigma _{SFR}$ and the underlying gas surface density $\rm \Sigma _{gas}$. In this work, we test various star formation scaling relations, such as the Kennicutt–Schmidt relation, the volumetric star formation relation, the orbital time model, the crossing time model and the multi free-fall time-scale model, towards the North American Nebula and Pelican Nebula and in the cold clumps associated with them. Measuring stellar mass from young stellar objects and gaseous mass from CO measurements, we estimate the mean $\rm \Sigma _{SFR}$, the star formation rate per free-fall time and the star formation efficiency for clumps to be 1.5 $\rm M_{\odot}\, yr^{-1}\, kpc^{-2}$, 0.009 and 2.0 per cent, respectively, while for the whole region covered by both nebulae (which we call the ‘NAN’ complex) the values are 0.6 $\rm M_{\odot}\, yr^{-1}\, kpc^{-2}$, 0.0003 and 1.6 per cent, respectively. For the clumps, we notice that the observed properties are in line with the correlation obtained between $\rm \Sigma _{SFR}$ and $\rm \Sigma _{gas}$, and between $\rm \Sigma _{SFR}$ and $\rm \Sigma _{gas}$ per free-fall time and orbital time for Galactic clouds. At the same time, we do not observe any correlation with $\rm \Sigma _{gas}$ per crossing time and multi free-fall time. Even though we see correlations in the former cases, however, all models agree with each other within a factor of 0.5 dex. It is not possible to discriminate between these models because of the current uncertainties in the input observables. We also test the variation of $\rm \Sigma _{SFR}$ with the dense gas but, because of low statistics, a weak correlation is seen in our analysis.

scholarly journals Research on the impact of ship traffic flow on the restricted channel segment of the middle Yangtze River based on traffic wave theory

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Ting Liu ◽  
Gabriel Lodewijks
Keyword(s):  
Traffic Flow ◽  
Flow Rate ◽  
Flow Simulation ◽  
Wave Theory ◽  
Flow Density ◽  
List Type ◽  
Ship Traffic ◽  
Traffic Wave ◽  
The Impact ◽  
Channel Segment

Abstract Abstract On the basis of the influence of dry season on ship traffic flow, the gathering and dissipating process of ship traffic flow was researched with Greenshields linear flow—density relationship model, the intrinsic relationship between the ship traffic congestion state and traffic wave in the unclosed restricted channel segment was emphatically explored when the ship traffic flow in a tributary channel inflows, and the influence law of multiple traffic waves on the ship traffic flow characteristics in unclosed restricted segment is revealed. On this basis, the expressions of traffic wave speed and direction, dissipation time of queued ships and the number of ships affected were provided, and combined with Monte Carlo method, the ship traffic flow simulation model in the restricted channel segment was built. The simulation results show that in closed restricted channel segment the dissipation time of ships queued is mainly related to the ship traffic flow rate of segments A and C, and the total number of ships affected to the ship traffic flow rate of segment A. And in unclosed restricted channel segment, the dissipation time and the total number of ships affected are also determined by the meeting time of the traffic waves in addition to the ship traffic flow rate of segments. The research results can provide the theoretical support for further studying the ship traffic flow in unclosed restricted channel segment with multiple tributaries Article Highlights The inflow of tributaries' ship traffic flows has an obvious impact on the traffic conditions in the unenclosed restricted channel segment. The interaction and influence between multiple ship traffic waves and the mechanism of generating new traffic waves are explained. The expression of both dissipation time of queued ships and the total number of ships affected in the closed and unclosed restricted channel segment are given.

scholarly journals The Departure Characteristics of Traffic Flow at the Signalized Intersection

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Zhaowei Qu ◽  
Yan Xing ◽  
Hongyu Hu ◽  
Yuzhou Duan ◽  
Xianmin Song ◽  
...  
Keyword(s):  
Traffic Flow ◽  
Wave Model ◽  
Wave Theory ◽  
Signalized Intersection ◽  
Departure Process ◽  
Dispersion Process ◽  
Spatiotemporal Model ◽  
Quantitative Calculation ◽  
Traffic Wave ◽  
Motion Characteristics

The motion characteristics of the leading vehicle and the following vehicles of the traffic flow at the typical urban intersections are qualitatively analyzed through the kinematical equation and the traffic wave theory. Then, the motion characteristic of the whole traffic flow during the dispersion process is also studied. Based on the spatiotemporal model of kinematics in the departure process and traffic wave model in the dispersion process proposed, the change of the leading vehicle of the departure process and the time of the following vehicles reaching to the stable speed as well as the relationship between the green time and the departure vehicle number at the intersection are acquired. Furthermore, according to the qualitative analysis and the quantitative calculation of the departure traffic flow at the signalized intersection, the dispersion characteristic of traffic flow at the signalized intersection was studied and analyzed, which provides reliable theoretical basis for traffic signal setting at the intersection.

scholarly journals Pengaruh Pelican Crossing terhadap Panjang Antrian dan Tundaan Kendaraan di Ruas Jalan Asia Afrika Kota Bandung (Hal. 18-27)

2018 ◽  
Vol 4 (2) ◽  
pp. 18
Author(s):  
Muhammad Reza Nugraha ◽  
Dwi Prasetyanto ◽  
Andrean Maulana
Keyword(s):  
Traffic Flow ◽  
Multiple Regression ◽  
Queue Length ◽  
Vehicle Traffic ◽  
Maximum Queue Length

ABSTRAKPelican crossing merupakan jenis penyeberangan yang dioperasikan oleh penyeberang jalan yang bertujuan memberikan keselamatan kepada penyeberang. Tujuan dari penelitian ini adalah menentukan jenis penyeberangan dan mencari pemodelan tundaan dan panjang antrian akibat pelican crossing di jalan Asia Afrika Bandung. Data penelitian ini adalah frekuensi penyeberangan, jumlah penyeberang, jumlah kendaraan terhenti, arus lalu lintas, tundaan dan panjang antrian kendaraan. Analisis penentuan jenis penyeberangan menggunakan perhitungan PV2  dan analisis pemodelan tundaan dan panjang antrian menggunakan regresi linier berganda. Dari perhitungan PV2 didapatkan hasil PV2=2,49*109 yang berarti termasuk kepada jenis penyeberangan pelikan dengan lapak tunggu. Model yang mewakili hubungan antara panjang antrian (Y) dengan jumlah kendaraan terhenti (X1) dan frekuensi penyeberangan (X2) adalah Y=2,201 + 3,203X1 + 3,510X2. Model yang mewakili hubungan antara tundaan  (Y) dengan variabel bebas yang sama adalah Y=0,709 + 2,656X1 + 7,645. Panjang antrian maksimum sebesar 78,072 meter dan tundaan maksimum sebesar 89,826 detik.Kata kunci: pelican crossing, panjang antrian, tundaanABSTRACTPelican crossing is a type of pedestrian cross which is operated by pedestrian with purpose is to give safety for the crosser. The aim of this study are to determine the type of crossing and find the model of delay and queue length because of pelican crossing at Asia Afrika Street Bandung. The data of this study are crossing frequency, amount of crossers, amount of stopped vehicle, traffic flow, delay and queue length vehicle. Analysis for the type of the crossing obtained by calculation of and analysis of model delay and queue length are use multiple regression. The result from the calculation of PV2  is PV2=2,49*109 which is the type of the crossing is pelican with protector. The represent model of relation between the queue length (Y) with amount of stopped vehicle  and crossing frequency (X2) is  Y=2,201 + 3,203X1 + 3,510X2.The represent model of relation between delay (Y) with same dependent variable is Y=0,709 + 2,656X1 + 7,645. The maximum queue length is 78,072 meters and the delay maximum is 89,826 seconds.Keyword: pelican crossing, the queue length, delay

The Trivariate Distribution of the Maximum Queue Length, the Number of Customers Served and the Duration of the Busy Period for the M/G/1 Queueing System

1969 ◽  
Vol 6 (1) ◽  
pp. 154-161 ◽  
Author(s):  
E.G. Enns
Keyword(s):  
Queue Length ◽  
Busy Period ◽  
Queueing System ◽  
Single Server ◽  
List Type ◽  
Type Number ◽  
Distribution Of The Maximum ◽  
Maximum Queue Length ◽  
Number Of Customers

In the study of the busy period for a single server queueing system, three variables that have been investigated individually or at most in pairs are:1.The duration of the busy period.2.The number of customers served during the busy period.3.The maximum number of customers in the queue during the busy period.

Application of Traffic-Wave Theory in Air Traffic Flow

Logistics ◽  
2009 ◽  
Author(s):  
Zhaoning Zhang ◽  
Xinhua Li ◽  
Lili Wang
Keyword(s):  
Traffic Flow ◽  
Wave Theory ◽  
Air Traffic ◽  
Air Traffic Flow ◽  
Traffic Wave

scholarly journals On the maximum queue length in the supermarket model

2006 ◽  
Vol 34 (2) ◽  
pp. 493-527 ◽  
Author(s):  
Malwina J. Luczak ◽  
Colin McDiarmid
Keyword(s):  
Queue Length ◽  
Maximum Queue Length ◽  
Supermarket Model
Sign in / Sign up

Export Citation Format

Share Document