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In urban traffic network, there is turning delays and turning prohibition etc. So it is more practical to use the algorithm considering delays at intersections than general algorithm to search optimal route. In order to save space, this paper proposes a new modified forward star storage structure, which can store road network with node turning delays. And we improve A* algorithm scientifically, road...
In view of the current widely used city intersection signal control system, oriented by the concept of automatic sensor signal control, this paper tries to use a computer's procedural method, with the input of initial conditions, after automatic calculation, a result which will make the vehicles go through the intersection causing the shortest signal control delay time totally will be generated automatically,...
According to the characteristics of the scope of the traffic impact of special events, this paper put the traffic of border roads in the affected areas as origin (O) and destination (D), researched the regular of the ratio of intersection turning and the traveler route choice behavior, proposed a new regional OD matrix estimation method based on the intersection turning. Examples showed that this...
Traffic signals are an elementary component of all urban road networks and play a critical role in controlling the flow of vehicles. However, current road transportation systems and traffic signal implementations are very inefficient. The objective of this research is to evaluate optimal phase ordering within a signal cycles to minimize the average waiting delay and thus in turn minimizing fuel consumption...
Increasing transportation network capacity is very important, particularly in congested traffic condition. In certain conditions, providing left turn green time could reduce intersection capacity because of: a) larger lost time due to added phase, and b) shorter green time for the through traffic movements. In this study, we will compare the effects of three ITS-based left turn policies on the performance...
Features of traffic flow, such as travel time, traffic volume, road choice, etc., are always important information for traffic planning and management. Conventional methods of collecting traffic flow features include loop detectors, closed-circuit televisions, field investigation, etc. They record vehicles' mobility in an indirect and infrastructure-based manner, and have difficulties in producing...
After analyzing the serious impact of left-turn vehicle on intersection, this paper offers the means of traffic organization by being use of U-turn for carrying out left-turn vehicles at intersection. Meanwhile, the paper gives the calculation models and reference values of design parameters about distance from intersection to U-turn hatch in center isolation, turn radius, and path width. The results...
Probe car system is used to provide real-time traffic information for telematics service. Although probe car technology is a well-known technology, how to appropriately evaluate the accuracy of a probe car system is still an unsolved issue. This paper compares several methods that are applied in the evaluation of probe car system. The shortcoming of each method is shown through data analysis of field...
To satisfy the needs of a variety of demand-responsive transport, the multimodal transportation problem appeared. This paper focuses on network modeling with a hierarchical structure. The relationship between different levels is described in detail, and dynamic segmentation and linear referencing techniques are used to solve the overlay problem in multimodal network. Furthermore, a shortest path algorithm...
As a widely available technology in China, the way of multi-quadrant optimized control which dividing plane traffic by time can improve the order and security in urban intersections. However, this method delays traffic and reduces passing capacity in urban intersections. Based on the actual situation of the main urban streets which have at least 6 lanes and 80% of the vehicles are small ones in China,...
Traffic control is both an efficient and effective way to alleviate the traffic congestion in urban areas. Model predictive control (MPC) has advantages in controlling and coordinating urban traffic networks. But, the real-time computational complexity of MPC increases exponentially, when the network scale and the predictive time horizon grow. To improve the real-time feasibility of MPC, a simplified...
Land use and investment are limited the development of traffic jams solution through the wide-ranging civil engineering method. The meticulous traffic design, such as regional traffic planning, intersection optimization design, pedestrian crossing optimization design traffic, operable management measure, can improve urban traffic conditions and ease the traffic jams. The meticulous traffic design...
This paper defined the emergency levels of the abnormal events. After knowing the effects on urban traffic system, it set forth the concept of characteristics and principles of emergency traffic organization. It considers that the virtual work of emergency traffic organization is in order to help the evacuating by transferring the right-of-way from the non-emergency trip to the emergency trip, the...
This study examined the difference of driving performance according to turn types (left /right turn), suggested by Bao and Boyle (2009), and age(old and young adults). To do that, the turn types at the intersection were divided into 12 scenarios of left and right turn, respectively and by making approach velocity at the intersection, the passing time at the intersection, the speed and steering variation...
T-shaped intersections are very common in urban street network for the constraints of space or other factors. They join the main road and the minor road together. In this paper, the capacity of unsignalized T-shaped intersection is investigated by a cellular automata model. Vehicles approaching from different direction will conflict with each other, because they are not controlled by traffic lights...
Road traffic safety is a complex problem which involves many factors as human, vehicle, road and environment and so on. For the road factor, the horizontal alignment can not be ignored, especially the horizontal curve. Although the accident rate happened on curve is higher than the straight line, it is inevitable to design horizontal curve. As the traffic accident becomes serious gradually, the paper...
Left-turn waiting area can improve the capacity and operational efficiency of the isolated signalized intersection. Based on the former researches and survey data, in this paper, we model the left-turn waiting area by dint of stop lines A, B and its length lAB, and parameters of left-turn signal, t1 ,t2 ,t3, t3. According to the flow chart and taking advantage of simulation software VISSIM, we emulate...
Traffic flow on roads is a non-linear, stochastic phenomenon, with complex interactions between vehicles. This paper discussed the dynamic nature of urban intersections, and presents a novel traffic flow evolution model at a time scale and of a level of detail suitable for on-line estimation, simulation and control. The intersection is considered as interconnected components of urban road network...
An increased mobility and the resulting rising traffic demands lead to serious congestion problems in many cities. Although there is not a single solution that will solve traffic congestion and the related environmental and economical problems, traffic light coordination is an important factor in achieving efficient networks. This paper presents a new distributed approach for dynamic traffic light...
A fuzzy logic control system by optimizing the signal time and phase change is developed in this paper. The first fuzzy controller is used to calculate the green extension time of current phase at the end of minimal phase time. The second fuzzy controller optimizes the phase change when there are no vehicles for the secondary flow of current phase at the intersection. Compared with fixed-time and...
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