A kinematic wave theory of multi-commodity network traffic flow

2012 ◽  
Vol 46 (8) ◽  
pp. 1000-1022 ◽  
Author(s):  
Wen-Long Jin
Keyword(s):  
Traffic Flow ◽  
Network Traffic ◽  
Wave Theory ◽  
Kinematic Wave

Influence of the Moving Bottleneck on the Traffic Flow on Expressway

2011 ◽  
Vol 97-98 ◽  
pp. 480-484 ◽  
Author(s):  
Qiao Ru Li ◽  
Yue Xiang Pan ◽  
Liang Chen ◽  
Chang Guang Cheng
Keyword(s):  
Traffic Flow ◽  
Wave Theory ◽  
Capacity Analysis ◽  
Kinematic Wave ◽  
Software Simulation ◽  
Low Speed ◽  
Traffic Capacity ◽  
Simulation Results

The mix rate of large trucks is extremely high on expressway in China. The influence of moving bottleneck on the traffic flow of the expressway is particularly serious. The moving bottleneck, formed due to the overtaking of the low-speed trucks, is analyzed with the kinematic wave theory and simulated by utilizing the VISSIM software. Simulation results indicate that increase of the traffic flow and the mix rate of trucks could aggravate the influence of the moving bottleneck on the traffic states, and decrease the speeds of cars significantly. This leads to the insufficient use of the expressway resources. The study result can contribute to the traffic capacity analysis of the expressway.

Kinematic wave theory of bottlenecks of varying capacity

1956 ◽  
Vol 52 (3) ◽  
pp. 564-572 ◽  
Author(s):  
S. C. De
Keyword(s):  
Shock Wave ◽  
Traffic Flow ◽  
Wave Velocity ◽  
Wave Theory ◽  
Kinematic Wave ◽  
Oncoming Flow ◽  
Unit Distance ◽  
Uniform Rate ◽  
Kinematic Waves ◽  
Flow Quantity

ABSTRACTThis paper discusses a problem in traffic flow by the method of kinematic waves developed by Lighthill and Whitham(1,2). The theory of kinematic waves introduced by Lighthill and Whitham has been extended here to include the case when the flow q varies with the time, and it is seen that the expression for the wave velocity is of the same form as before, namely, ∂q/∂k, where q is the flow (quantity passing a given point in unit time) and k is the concentration (quantity per unit distance). The theory is applied to the problem of estimating how a uniform oncoming flow behaves on entering a bottleneck, the capacity of which varies with time. This capacity has initially a higher value than the oncoming flow but falls at a uniform rate to a lower value, where it remains constant for a time, and again rises at a uniform rate to the original value. A shock wave is found to move back from the bottleneck, and later forward again and through it, much as in the case of a bottleneck of constant capacity with varying oncoming flow studied by Lighthill and Whitham.

Simple, Generalized Method for Analysis of Traffic Queue Upstream of a Bottleneck

1998 ◽  
Vol 1646 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Alan L. Erera ◽  
Tim W. Lawson ◽  
Carlos F. Daganzo
Keyword(s):  
Traffic Flow ◽  
Piecewise Linear ◽  
Wave Theory ◽  
Flow Density ◽  
Cumulative Number ◽  
Kinematic Wave ◽  
Input Output ◽  
Original Technique ◽  
Time Space ◽  
Bottleneck Capacity

An approach is generalized for enhancing a standard input-output diagram to represent graphically the time and distance that vehicles spend in a queue upstream of a bottleneck. The approach requires the construction of a curve depicting the cumulative number of vehicles to have reached the back of the queue as a function of time. The original technique, described in a previous paper, is reviewed for bottlenecks with constant capacity and for those where capacity changes once. The approach is then generalized to allow multiple changes in bottleneck capacity, and the original assumption of a triangular flow-density ( q-k) relation is relaxed to one that is piecewise-linear concave. Although it is consistent with the kinematic wave theory of traffic flow, the proposed approach is simpler to apply to complex problems because it avoids the laborious construction of a time-space diagram. It allows the estimation of several measures required in the evaluation of the impacts of bottlenecks, including the (accurate) number of vehicles in queue and the physical extents of queues at any time and the total time spent by vehicles in different traffic states.

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.

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