CFI brings road revolution

According to traffic police in Shenzhen, the new technology Continuous Flow Intersection (CFI) is proving its value as it's applied to Shenzhen traffic.

On Oct 7, the country's first CFI was used in the Caitian-Fuhua Road in Shenzhen. After a week of observation, the traffic capacity of the road increased by 29 percent, with 1,223 more cars passing through per hour than usual.

CFI, also called a crossover displaced left-turn, is an alternative design for an at-grade road junction. Vehicles attempting to turn across oncoming traffic make their turn before they enter the intersection. No left turn signal in the intersection is necessary. Instead, vehicles traveling in both directions, including through-vehicles and those turning right or left, can proceed when a generic traffic signal/stop sign permits.

Caitian-Fuhua Road used to suffer from heavy traffic jams due to metro construction and conventional traffic organization. For this reason, authorities rebuilt the road section to coordinate with the first center of the Shenzhen Metro using the new signaling system.

After reconstruction, the total traffic flow increased from 4,218 pcu/h to 5,441 pcu/h. The most congested south entrance has increased its efficiency by 57.6 percent, with 668 more cars passing through per hour than before.

Due to the reduction of traffic phases, Shenzhen traffic police reduced the original 180 seconds signal cycle to 140 seconds, which reduced the wait-time for a light change in all directions. The average intersection delay was therefore reduced by 24.1 percent.

CFI is set to become standard at every at-grade road junction in the country after this test trial, according to a Shenzhen traffic police representative.