The effect of green wave belt is affected by intersection geometry, intersection spacing, traffic flow status, traffic conditions and communication conditions. For a simple example, if a road is equipped with a green wave band, it may attract more vehicles to enter the road. At this time, the traffic flow of the road will change, and the original green wave band setting may be invalid.
In order to ensure the normal operation of the green belt, it is necessary to effectively manage and maintain the green belt, master the real-time changes of various factors, and timely adjust the coordination scheme between intersections.
【Common green belt maintenance methods】
1. Traffic flow changes. Before the flow saturation, the main function of the green wave band is to "timing follows the flow" to ensure the maximum realization of the green wave band function. After the flow is saturated, its main function is to "the flow follows the timing", that is, to adjust the traffic flow timely and reasonably. In the peak and flat peak, it is necessary to set a variety of schemes for the coordination period, absolute phase difference and other parameters for the green wave band.
2. Road channelization changes. Reasonable channelization means that people and vehicles can pass safely and orderly in space and time according to the allocation instructions of signal lights to reduce conflicts. When the road channelization situation changes, the road driving environment changes, the lateral and longitudinal interference increases, the driving speed decreases, and the travel time becomes longer. Accordingly, it is necessary to reset the coordination scheme between intersections.
3. Green letter ratio changes. The change of green signal ratio will change the effective time of vehicles passing through the intersection in the signal cycle. The change of the upstream intersection will not only affect itself, but also affect the traffic condition of the downstream intersection. The influence of the change of green signal ratio can be solved by adjusting the phase difference directly.
4. Traffic signal clock calibration. The traffic signal is installed near the intersection and exposed to the air. It is easy to be disturbed by external factors such as magnetic field, so it is necessary to calibrate the clock. During calibration, a computer with high stability can be used in the command center to set the time of each intersection signal.
5. Green wave guide. The realization of the green wave band function depends on the driver driving at the specified speed. Due to the influence of weather, driving conditions and other factors, the optimal driving speed of green wave belt will change dynamically. In order to maximize the effectiveness of the green wave band, it is better to set up led guidance screen at the entrance of the green wave band to prompt the driver of the recommended driving speed of this section.
1. The frequency of fine-tuning the system according to the change of traffic flow is approximately every 2-3 times / month.
2. Complete the system inspection every three months.