Shenzhen Road Continuous Flow Intersection (CFI)

Shenzhen Traffic Police

On October 7, 2017, the Shenzhen Traffic Police introduced the country's first Continuous Flow Intersection (CFI).

Due to the subway construction at the Caitian Road-Fuhua Road intersection in Shenzhen, the southward and northward sections of Caitian Road were separated and seriously misplaced. In addition to the traditional traffic organization, the traffic congestion at the intersection was more serious than before. To this end, the Shenzhen Traffic Police, together with the Metro Group, reorganized the road section with the opportunity of subway traffic relief. The Shenzhen Traffic Police and the Metro Group displaced the left-turn area to the opposite side of the oncoming traffic in the north-south section of Caitian road, retreated the east-west stop line and optimized the vehicle turning radius. The non-retrograde sign, the intersection guide line with night reflective spikes, two sets of reverse control traffic lights and two sets of left shift position indicator lights were also set up, and the LED indicator screen was used to guide the vehicle to advance into the left lane in the signal time difference. The straight-going vehicles in two-way north-south direction and the left-turning vehicles of Caitian Road could move simultaneously, and the original 4-phase organization was simplified into a 3-phase organization. Meanwhile, the six misplaced straight lanes were reset to straighten the road line.

After launching the CFI, the total flow rate of the intersection increased from 4218pcu/h to 5441pcu/h (equivalent to add 1,223 vehicles per hour), and the traffic capacity increased by 29%. Among them, the traffic efficiency of the most congested south import increased by 57.6%, which meant that 668 more vehicles could pass per hour. Therefore, the queue length of the south import was shortened by 215 meters with 160 meters shortened for the east import, and the road traffic efficiency was significantly improved. Consequently, the Shenzhen Traffic Police shortened the original 180-second signal period to 140 seconds, which greatly reduced the waiting time for the red light in all directions, and the average delay of the intersection decreased by 24.1%.

The total flow rate of the intersection increased from 4218pcu/h to 5441pcu/h (equivalent to add 1,223 vehicles per hour), and the traffic capacity increased by 29%. Among them, the traffic efficiency of the most congested south import increased by 57.6%, which meant that 668 more vehicles could pass per hour. Therefore, the queue length of the south import was shortened by 215 meters with 160 meters shortened for the east import, and the road traffic efficiency was significantly improved. Consequently, the Shenzhen Traffic Police shortened the original 180-second signal period to 140 seconds, which greatly reduced the waiting time for the red light in all directions, and the average delay of the intersection decreased by 24.1%.

CFI will be used at more road intersections in proper situation.

INNOVATION POINT

By setting the left-turning lane and reorganizing the road section, vehicles going straight line or tuning left can move simultaneously, thereby reducing the signal phase and improving the efficiency of the entire intersection.

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ATTACHMENT

News report