LED traffic display to create intelligent transportation

In the research and development of intelligent transportation system, one of the main means to solve urban traffic congestion, ensure road traffic safety, and improve the efficiency of traffic road network is to establish a traffic guidance information system, which is also an important part of intelligent transportation system. The function of the traffic guidance information system is to issue various traffic notices and related traffic information in a timely manner according to the road traffic conditions or the instructions of the management department, so as to effectively guide the traffic flow, reasonably control and balance the distribution of road traffic flow, and improve the existing traffic flow. The utilization rate of the road provides a good service for drivers and vehicles to drive safely and quickly.

1 Traffic guidance and LED display

Intelligent Transportation System (ITS) is a comprehensive application of advanced information technology, data communication transmission technology, electronic control technology and computer processing technology to the entire transportation management system. Through the real-time collection, transmission and processing of traffic information, with the help of various scientific and technological means and equipment, various traffic conditions are coordinated and processed; a real-time, accurate and efficient comprehensive transportation management system is established, so that traffic facilities can be Make full use of and can improve traffic efficiency and safety, and ultimately make transportation services and management intelligent, and realize the intensive development of transportation.

Traffic guidance information system is one of the keys to the function of Intelligent Traffic Management System (ITS). Various subsystems in ITS coordinate with each other to collect, process and analyze traffic information, and provide effective information to traffic managers and travelers. Information collection, information processing, generation of guidance information and release of guidance information constitute an intelligent urban traffic guidance information system.

In the traffic guidance system, the guidance information release is divided into two types: individual-oriented and group-oriented according to the different recipients of the information.

The individual oriented traffic guidance information is generally received through the traveler's in-vehicle equipment, which includes GPS positioning, navigator and other devices; the group-oriented guidance information release methods include traffic guidance outdoor LED display, wireless broadcasting, TV, Internet , telephone inquiries, etc. Among them, the more effective means are traffic broadcasting and traffic guidance outdoor LED display installed on the road, which is also the main way to release traffic guidance information that has been widely developed and widely used.

Generally, the urban road traffic guidance information system includes three aspects: basic traffic information collection and processing, traffic guidance algorithm and guidance information generation, and guidance information release and display.

2 The use function of traffic guidance information LED display

The production and application of LED display screens involve semiconductor optoelectronic device technology, electronic circuit technology, integrated circuit technology, information image processing and transmission technology, computer network communication technology, and technologies related to electronic product manufacturing and electronic product installation engineering. LED displays of different types and performances are quite different in terms of material composition, production process, control technology, etc., and the technical connotations are obviously different. Even for products of the same type and performance, different manufacturers use different technologies. different. The outdoor LED display for traffic guidance information, according to the requirements of road traffic management and the actual situation of the release and display of traffic guidance information, has the following characteristics in terms of specific use functions:

2.1 High brightness, reasonable viewing angle

The release of road traffic guidance information is mainly for vehicles on the road, and the viewing angle of the display screen is not high, and it is generally about ±35° on urban roads. The outdoor LED display for traffic guidance works continuously for 24 hours. In the case of direct sunlight on the surface of the display, the display content should be clearly visible, so high brightness is required. Under normal circumstances, the visual distance is required to be about 200m.

2.2 The display color is mainly red, green and yellow

The release of traffic information is mainly for dynamically moving vehicles. The staying time of moving vehicles within the visible distance is very short. Therefore, the use of complex multi-grayscale graphics and animation content should be avoided, and the display content should be mostly text and simple. Graphic logo. Considering the common colors of traffic sign signals, red, green and yellow displays are usually used. The three colors of red, green and yellow can respectively display prohibition, instruction suggestion and warning information.

2.3 Display brightness can be adjusted automatically

The outdoor LED display of traffic guidance information works 24 hours a day, and the environmental illumination changes greatly. It is necessary to ensure that the display screen is clearly visible when the maximum ambient illuminance is on a sunny day and 100 days, and to avoid the "glare" phenomenon in rainy days and nights, the brightness of the LED display needs to be automatically adjusted according to the ambient illuminance. Under normal circumstances, the automatic adjustment of the brightness of the outdoor LED display for traffic guidance should be above level 8.

2.4 All-weather work, complex environmental conditions

Traffic guidance LED display works under completely outdoor conditions, the environment is complex, and the requirements in terms of temperature, power supply, rain resistance, moisture resistance, corrosion resistance, lightning protection, etc. are complex, and at the same time, high reliability is required. Take specific targeted measures. In the structural design of the outdoor LED display for traffic guidance information, attention should be paid to the heat dissipation, waterproofing and dustproofing of the display body. The unit box structure design of the display screen should meet the requirements of IP65 protection grade.

2.5 Remote control, intelligent detection

The installation positions of traffic guidance LED display screens are distributed in a large area, and are generally controlled remotely by the control center. The daily maintenance and detection of the display screen is difficult, so it must have corresponding remote control and fault diagnosis and detection functions. Generally, the temperature of the box should be automatically detected and adjusted, so that the LED works within an appropriate temperature range to ensure the service life of the display.

2.6 High requirements for security, real-time, accuracy and reliability

Traffic guidance information is released to the public and requires high real-time, accuracy and reliability. In order to ensure the stability and reliability of the traffic guidance LED display, the display control system and software are used. The selection and quality requirements of LED pixel tubes, integrated circuits, etc. should be stable and reliable. At the same time, the traffic guidance LED display generally works in a network environment and publishes public information, which also has higher requirements for security.

In addition, the traffic guidance outdoor LED display system also needs to comprehensively consider many factors such as placement location, display type, technical parameters, system control, product structure, and supporting projects.