Discussion on Urban Intersection Theory and Design In order to alleviate the huge traffic pressure, a very important measure is to adopt a more efficient road design. The urban intersection is an important node, and it is the throat of traffic. It plays an important role in regulating traffic flow and diverting traffic pressure. Therefore, a reasonable urban intersection design can greatly improve the efficiency of traffic operations.
The theoretical design of urban intersections, the status quo of urban intersections and the existence of problems The development of urban transportation is a reflection of people's living standards and economic development. With the rapid development of China's economy, the population is growing, the number of motor vehicles is also growing rapidly, and the demand for urban roads is increasing. The Chinese government has also strongly supported the construction of infrastructure such as urban roads, and has also achieved certain results.
However, due to the rapid development and unclear planning, in the construction of the urban transportation system, some serious problems such as traffic congestion, disorder, and frequent accidents have appeared.
At the same time as the traffic pressure is huge, the demand for motor vehicles is still growing rapidly. Although major cities have introduced motor vehicle purchase restrictions, it is still difficult to block the enthusiasm of the people. As the number of vehicles is growing, the problem of traffic congestion is getting worse. Not only that, but it also caused a very serious collateral problem, such as air pollution caused by automobile exhaust.
Such a serious traffic problem puts higher demands on the design and construction of the road. As an important part of the urban transportation network, urban intersections play a key role in relieving traffic pressure. In traffic roads, the intersection is the place with the slowest traffic speed, and it is the place where the traffic is converged, so it is also the most congested place. Statistics show that the main reason for daily traffic congestion is the lack of capacity at the intersection of cities. If the urban intersection is properly designed, it can greatly alleviate the traffic pressure.
After clarifying the important role of urban intersections, a lot of research work has also been carried out. Although China's research on urban intersections started late, it has developed rapidly. The research team headed by Beijing University of Technology and Tongji University has made a comprehensive study on conflict control methods, lane design, and lane width. However, the theory of urban intersections is not universal. The premise of design is to statistically study the specific traffic flow at specific locations.
2. Urban intersection theory 1. Basic requirements and contents of urban intersections Urban intersections are a key component of urban transportation networks. Pedestrians and motor vehicles gather, pass and turn at intersections. In this process, pedestrians with different purposes Vehicles can interfere with each other. Not only will it seriously affect the traffic capacity of the road, but it will also cause certain security risks. Therefore, urban intersections should meet some basic requirements to ensure orderly traffic, smooth roads and personal safety.
Urban intersections should meet two basic requirements. One is to ensure that pedestrians and vehicles with different driving purposes can pass through the intersection safely and efficiently, and the other is that the various routes of the intersection should be designed reasonably. In order to ensure the safe and smooth driving of the vehicle, such as the turning radius can not be too small.
In order to meet such basic requirements, urban intersections should be comprehensively considered in the design, including the choice of intersection type, the layout of intersection traffic facilities, the organization of intersections, the determination of intersection speed, and the viewing distance of intersections. Determination, intersection drainage pipe design, etc. In the design and construction of urban intersections, each aspect is not independent, and there is more or less connection between them. Only by considering and rationally designing can the urban intersection meet its basic requirements.
In order to ensure the capacity and security of urban intersections, urban intersections must meet some principles that are summed up in practical work and theoretical research.
The two intersecting roads at the intersection of urban roads should be orthogonal to ensure the smoothness of driving. If it is necessary to construct with obliqueity due to environmental factors, it should be ensured that the acute angle between the two roads is greater than 45°. Otherwise, it will bring great inconvenience to the driving, resulting in a safety accident.
The design of the type and shape of urban intersections should be based on specific circumstances. Considering local geological conditions, building conditions, and traffic flow, pedestrian flow, and speed of travel, the design is specifically carried out.
The traffic signal organization design of urban intersections should be complete. In particular, pay attention to situations that are prone to traffic accidents, such as turning lanes, turning lanes, and parallel roads. Traffic signs must be designed in conspicuous positions.
In the urban intersection area, there must be no obstacles that may obscure the line of sight. If the vehicle is blocked when the vehicle enters the intersection and the signal light or the vehicle in front cannot be observed, it will cause serious traffic accidents and traffic congestion.
A very important parameter in urban intersections is the intersection line of sight. The determination of the line of sight of the intersection directly affects the driving safety of the vehicles in the intersection. When determining the line of sight of the intersection, it is necessary to take into account factors such as the width of the lane, the length of the turning lane and the angle to ensure that the field of view is sufficiently wide when driving. After the construction is completed, it should be tested to ensure safety before it can be put into use.
The first type of information needed for the information needed to construct a city intersection is the local traffic situation. It is necessary to consider the traffic volume, the speed of the vehicle, the type of vehicle, etc., based on these data, to determine the capacity and capacity of the intersection of the city.
The second type of information needed is the local location. Including the road setting and construction situation of the local section, as well as the distribution of schools and institutions, to select the appropriate intersection type and organization.
Third, the design and method of urban intersections The organizational design of intersections should be based on local specific traffic conditions, and it is appropriate to find the most appropriate organization. Below, the organization of the intersection is described by way of a specific example.
If the vehicle type includes a bus or there is a nearby emergency center, you can set up a dedicated lane. And the dedicated lane is generally designed on the right side of the road to facilitate its passage.
In the setting of the turning lane at the intersection of the city, it is necessary to ensure that the turning vehicle does not affect the cars of other lanes, and can be organized by means of traffic lights. In some cases, it can also be organized in a circular way, so that conflicting confluence and parallel vehicles can be avoided.
Determination of the number of intersection lanes When designing lanes and determining the number of lanes, it is necessary to consider not only the environmental factors such as the width of the road and the characteristics of the surrounding buildings, but also the traffic factors such as local traffic volume and vehicle type. It is best to adopt a model that can be quantified, take these parameters as input variables, and then calculate parameters such as the number of straight lanes and the number of turns lanes, so that it can be adapted to the characteristics of local traffic flow as the final criterion for judging the design effect.
For vehicles entering the intersection, the driver can clearly observe all the traffic conditions at the front intersection. And when there is a dangerous situation, there is enough time to brake the vehicle, such line of sight can be regarded as a safe line of sight. In order to achieve this goal, it is necessary to take into account the width of the straight road, the length of the turning road, and the local average driving speed. After the design is completed, tests are also carried out to test its safety.
IV. Conclusion This paper introduces the theory and design methods of urban intersections in detail for the problems existing at urban intersections, and provides concrete and feasible theories and methods for urban intersection design. When designing a city intersection, it is necessary to select the appropriate intersection type according to the specific traffic conditions and location of the local area, determine the corresponding traffic organization, and determine the intersection distance and other content.
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