Analysis on the Road Capacity: Connected and Automated Vehicle Platoons in the Mixed Traffic Flow

Author(s):  
Ke Ma ◽  
Hao Wang
2017 ◽  
Vol 2622 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Da Yang ◽  
Xiaoping Qiu ◽  
Lina Ma ◽  
Danhong Wu ◽  
Liling Zhu ◽  
...  

In recent years, automated vehicles have been developing rapidly, and some automated vehicles have begun to drive on highways. The market share of automated vehicles is expected to increase and will greatly affect traffic flow characteristics. This paper focuses on the mixed traffic flow of manual and automated vehicles. The study improves the existing cellular automaton model to capture the differences between manual vehicles and automated vehicles. Computer simulations are employed to analyze the characteristic variations in the mixed traffic flow under different automated vehicle proportions, lane change probabilities, and reaction times. Several new conclusions are drawn in the paper. First, with the increment of the proportion of automated vehicles, freeway capacity increases; the capacity increment is more significant for single-lane traffic than for two-lane traffic. Second, for single-lane traffic flow, reducing the reaction time of the automated vehicle can significantly improve road traffic capacity—as much as doubling it—and reaction time reduction has no obvious effect on the capacity of the two-lane traffic. Third, with the proportion increment of automated vehicles, lane change frequency reduces significantly. Fourth, when the density is 15 < ρ < 55 vehicles/km, the addition of 20% automated vehicles to a traffic flow that consisted of only manual vehicles can decrease congestion by up to 16.7%.


2013 ◽  
Vol 27 (08) ◽  
pp. 1350052 ◽  
Author(s):  
HAN-TAO ZHAO ◽  
HONG-YAN MAO ◽  
RUI-JIN HUANG

Two kinds of cellular automaton models are proposed for mixed traffic flow with emphasis on emergency vehicles. By analyzing the characteristics of ordinary vehicles in giving way to emergency vehicles, the rules for changing lanes are modified. Computer numerical simulation results indicate that an emergency vehicle without changing lanes can enhance speed with density lower than 0.1, while its speed can be enhanced by changing lane with density greater than 0.1. Meanwhile, vehicle speed and density within a certain range around emergency vehicles are lower than the road section average velocity and average density. The passage way of emergency vehicle that facilitate lane change causes less interference than that of an emergency vehicle which is unable to change lane. The study found that the physical characteristics of traffic flow when there are emergency vehicles are significantly different from routine traffic flow. Emergency vehicles can facilitate their passage by changing lanes at a medium or high density.


Author(s):  
Xiaobao Yang ◽  
Ziyou Gao ◽  
Xiaomei Zhao ◽  
Bingfeng Si

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Chenhao Dong ◽  
Rongguo Ma ◽  
Yujie Yin ◽  
Borui Shi ◽  
Wanting Zhang ◽  
...  

In recent years, with the rapid development of China’s logistics industry and urban service industry, electric bicycles have gradually become an important means of transportation in cities due to their flexibility, green technology, and low operating costs. Because electric bicycles travel though motor vehicle lanes and nonmotor vehicle lanes, the conflict between motor and nonmotor vehicles has become increasingly prominent, and the safety situation is not optimistic. However, most theories and models of mixed traffic flow are based on motor vehicles and bicycles and few involve electric bicycles. To explore the traffic safety situation in an urban mixed traffic environment, this paper first uses cellular automata (CA) to establish a three-strand mixed traffic flow model of motor vehicles, electric bicycles, and bicycles and verifies the reliability of the model by using a MATLAB simulation based on the actual survey data. Then, using the technology of traffic conflicts and the conflict rate as the index to evaluate the traffic safety situation, the change in the conflict rate with different road occupancies and different proportional coefficients of motor vehicles is studied. In the end, the conflict rate is compared between the mixed traffic flow and the setting of a physical isolation divider, which provides some suggestions on when to set a physical isolation divider to separate motor vehicles from nonmotor vehicles. The results show that in a mixed traffic environment, the conflict rate first increases and then decreases with increasing road occupancy and reaches a peak when the road occupancy is 0.6. In addition, in mixed traffic environments, the conflict rate increases with an increasing proportional coefficient of the motor vehicle. When the road occupancy rate is within the range of [0.6, 0.9] or when the proportional coefficient of motor vehicle is between [0.8, 0.9], a physical isolation divider can be set to separate motor vehicles and nonmotor vehicles from the space to improve traffic safety.


CICTP 2020 ◽  
2020 ◽  
Author(s):  
Mengyan Hu ◽  
Fei Hui ◽  
Xiangmo Zhao ◽  
Xia Wu ◽  
Jingru Guo

SIMULATION ◽  
2017 ◽  
Vol 94 (5) ◽  
pp. 451-462
Author(s):  
Peng Dong ◽  
Xifu Wang ◽  
Lifen Yun ◽  
Hongqiang Fan

Mixed traffic flow is a main feature of urban traffic in developing countries. Mixed bicycle flow includes human-powered and electric-powered bicycles and plays an important role in this mixed traffic flow. In mixed bicycle flow, cyclist behavior is flexible and variable. Cyclists move arbitrarily in the road and may influence the vehicle flow at intersections. Therefore, we first propose an improved bicycle model that can reproduce the main features of cyclist behavior, such as overtaking and self-protection. Then a simulation model based on the improved bicycle model is proposed to research the characteristics of mixed traffic flow in intersections. The conflict avoidance rules are then applied in the simulation model to eliminate traffic accidents. The simulation results indicate that the improved bicycle model is practical and that the density–velocity diagram of bicycle flow is similar to real traffic data. The existence of bicycle flow decreases vehicle velocity and worsens traffic flow in mixed traffic flow. However, the influence of bicycle flow might disappear at a particular vehicle density.


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