chrispeng [ad_1]
City of Los Angeles Automatic Traffic Monitoring and Control Center
The Los Angeles Automatic Traffic Monitoring and Control Center (ATSAC) began construction before the 1984 Olympic Games. It was initially limited to the Los Angeles Memorial Stadium area, the main venue of the Olympic Games, and then gradually expanded to the entire city.
Currently, ATSAC in Los Angeles controls 2,449 intersections with signal control. There are 4285 signal-controlled intersections in Los Angeles, and ATSAC controls 57% of them. Another ATSAC project at 286 intersections is under construction.
Within ATSAC, the computerized traffic control system monitors the city’s traffic conditions and system performance. The induction loop buried on the road can monitor the passage, speed and flow of vehicles, and modify the data every second. In addition, about 150 CCTV cameras have been installed in the city.
The automatic traffic monitoring and control center can expand the system by adding software to monitor other vehicles, such as light rail. The latest technological development of ATSAC is to build an adaptive traffic control system (ATCS), which can adjust the signal time according to the traffic volume of the vehicle, so that the traffic capacity of the road can be used most effectively.
Los Angeles City Bus Signal Priority Technology
The Los Angeles City Bus Signal Priority Technology is the application of Intelligent Transportation System (ITS) technology to increase the speed of buses, making buses more punctual and improving their operating efficiency.
The main method is to give a green light to the late bus at the intersection in advance at the red light, and at the same time extend the green light time for the late bus traveling in the intersection to allow enough time to pass the intersection. Generally speaking, it is not necessary to give priority to signals for buses that are on time. The key to bus signal priority technology is to ensure that there is wireless communication between the bus and the intersection signal.
The bus signal priority process includes four stages:
The first stage: Determine the location of the bus. Determine the place where the bus arrives to determine whether the intersection needs signal priority. This function also provides location data to the processor on the bus to determine if the car is late.
The second stage: The bus makes a signal priority request to the signal at the intersection. It is executed by the processor on the bus, and decides whether or not to provide signal priority after the car reaches the set point.
The third stage: The signal at the intersection agrees to the signal priority request made by the bus. Whether or not to give priority to the signal depends on many factors, such as the possibility of a manual forcible signal light turning green during the time of the day, local traffic conditions, and the condition of the signal machine. This process is generally carried out at intersections, but sometimes it may be necessary for the public transportation planning and management personnel of the Municipal Transportation Bureau to agree to the signal priority request made by the bus.
The fourth stage: implement signal priority. According to the relative position of the bus and the front intersection, adjust the signal time through the signal to make the signal light turn green in advance, or extend the green light time, so that the bus can pass the front intersection smoothly.
[ad_2]
