19 August 2022

Around the World with Yunex Traffic: Hong Kong

Light up for less waiting time: an adaptive real-time traffic signal system optimizes traffic flow in Hong Kong

The traffic signal control system is an indispensable facility of our road network, regulating the high traffic volume in Hong Kong while ensuring the safety of road users. Conventional traffic signal control systems generally use a pre-determined green time allocation and therefore cannot flexibly adjust green times to match real-time pedestrian and vehicle flows. This causes unnecessary delays for road users.

To address this problem in Hong Kong, the Department of Transport (TD) launched the Real-Time Adaptive Traffic Signal System pilot project. Using sensor and analysis technologies, real-time data on traffic flow intersection will be collected at intersections to automatically set the optimal green time.

How does the adaptive traffic signal system work?

By installing sensors on traffic light poles, real-time data about the flow of traffic at an intersection can be collected. These include, for example, the length of the queue and the number of waiting pedestrians. Based on this data, the optimal allocation of green times can be determined.

The system is operated 24/7. This allows traffic signal control to be adapted to sudden changes in traffic volumes at different times of the day and during incidents. 

What technology will be used to collect real-time traffic data?

Various technologies such as radar, thermal detection and video analysis are used worldwide to collect real-time traffic data. Which technology is used in each case depends on the type of data required. In this pilot project, radar/heat detection technology will be used first. Then, its effectiveness will be verified. The proposed radar used in the pilot project complies with the EU standard EN62311 – Assessment of electronic and electrical equipment related to human exposure restrictions for electromagnetic fields (0 Hz to 300 GHz).

What data will be collected from the system?

The system will only capture the amount of vehicle and pedestrian flow within the detection area of the intersection. It will not capture personal data such as the identity or appearance of pedestrians and vehicles.

How effective can the system be in improving traffic at junctions?

Depending on the design of the intersection and the method of control of the traffic signals, as well as the actual variation of traffic flows, overseas experience shows that real-time adaptive traffic signals can reduce traffic delay up to 10% - 50%. In general, where a intersection exhibits large and irregular variation of traffic flows, e.g., near schools or large community facilities/venues, we can make optimal use of the System to reduce delays and avoid congestion/crowdedness at the intersection.

What are the benefits for the city?

  • Waiting time at traffic lights is reduced for motorists as well as pedestrians and cyclists.
  • Congested intersections are relieved at peak times.
  • Unexpected changes in traffic flow can be handled more easily.