HKeToll - Free-Flow Tolling System for Hong Kong Government Tolled Tunnels

We are deeply involved in the development of the fundamental data acquisition system (DAS) for Hong Kong's Free-flow Tolling System, now known as HKeToll, which aims to realise and promote the smart mobility ambitions of the city.

Location

Hong Kong

Client

Electrical and Mechanical Services Department, HKSAR Government

Developing the Free-flow Tolling System (FFTS) for motorists to pay tunnel tolls by remote means is one of the major smart mobility initiatives stipulated in the Hong Kong Smart City Blueprint issued in December 2017. The FFTS, now known as HKeToll, is planned to be rolled out in three phases for eight government tolled tunnels and the Tsing Sha control area, with full implementation expected by 2025.

As the design and construction consultant appointed by the Electrical and Mechanical Services Department, WSP is responsible for the implementation of the data acquisition system (DAS) of the FFTS starting from Phase 2 for six major government tolled tunnels, including Aberdeen Tunnel, Western Harbour Crossing, Tate’s Cairn Tunnel, Eastern Harbour Crossing, Cross Harbour Tunnel, and Tai Lam Tunnel.

We also provide multidisciplinary construction support as the Engineer's Representative, which involves reviewing site constraints of existing tolled tunnel areas, identifying necessary works for DAS implementation with utmost accuracy, carrying out interface works with the back-end system, and ensuring a smooth transition to FFTS.

Bringing value to road users

Tolls often create significant bottlenecks in traffic flow, especially during peak periods in a densely populated city like Hong Kong. FFTS eliminates the need for physical barriers and transforms tolling into an automatic activity. Motorists are no longer required to stop or queue at toll booths to pay tunnel tolls manually, resulting in smoother driving and improved traffic flow near the tunnels. This seamless journey experience also enhances fuel efficiency, road capacity, and overall user satisfaction, thereby maximising efficiency across existing transportation networks.

Moreover, the implementation of HKeToll allows for the demolition of existing toll booths at toll plazas, freeing up space for alternative purposes. For instance, at the Western Harbour Crossing, the relocation of its Administration Building is made possible, which enhances traffic connectivity and contributes to the long-term growth of the nearby Western Kowloon Cultural District.

Identifying the right smart technologies

Our team of smart solution technical experts conducted a comprehensive study and comparison of various market-available in-vehicle units (IVU) technologies. Taking into account cost-effectiveness and feasibility within Hong Kong's unique road environment, including high traffic volume, driver behavior, vehicle types, and license plate styles, we designed the DAS as the front-end system, leveraging the latest smart technologies such as:

Radio Frequency Identification (RFID): Utilising ISO/IEC 18000-6C RFID to identify and track tags.
Automatic Number Plate Recognition (ANPR): Adopting multiple high-resolution cameras and deep learning technology to capture and extract vehicle registration marks from both the front to rear in still images.
Light Detection and Ranging (LiDAR) Technology: Utilising LiDAR sensors to detect vehicle speed, trajectory, location, dimensions, and features for accurate vehicle classification.

These three detection technologies operate simultaneously in the detection zone, complementing each other and ensuring sufficient data collection for every passing vehicle. This enhances the efficiency and accuracy of the DAS and the overall toll collection mechanism.

Equipment installed at the detection zone, including RFID and LiDAR sensors, and high-resolution cameras

HKeToll vehicle tag affixed to the front windscreen of a car for RFID detection

Mitigating data privacy and security concerns

Data privacy and cybersecurity are significant challenges associated with data connections. HKeToll collects videos, images, and data, stores vehicle data locally, and transmits live data to the backend system for vehicle identification and toll collection. To address privacy concerns, we conducted privacy impact assessments, masked irrelevant areas on captured images, and developed documentation and handling guidelines for the data collected by HKeToll DAS. We also implemented measures to mitigate security risks, including security risk assessments, encrypted and secured communication channels for external interfaces, access restrictions to the HKeToll server and outstation hardware, training programs, and the development of documentation and handling guidelines for accessing HKeToll workstations or servers.

Tailored setting for detection accuracy

To ensure RFID detection accuracy, we conducted extensive test runs in specific environments. For example, Cross-Harbour Tunnel, Hong Kong's first and busiest road link crossing the Victoria Harbour, is relatively narrow and the tunnel’s beam elevation, low headroom, other existing devices and signages could block camaras to capture different vehicles. We conducted a sightline analysis on the Kowloon side to ensure that the FFTS equipment in the four beam areas is unobstructed. We also determined the optimal firing angles for RFID antennas and ANPR cameras.

To measure detection accuracy in different traffic scenarios, we arranged temporary overhead RFID systems using scissor lifts. Multiple cars with toll tags adhered on different locations were then assigned to pass through the RFID devices in a specific order. Due to the vast traffic volume in daytime and noise restrictions, test runs, installation and maintenance work could only be conducted during nighttime hours in the tunnels.

Low beams and headroom of Kowloon entrance of Cross-Harbour Tunnel

We determined the optimal setting of FFTS equipment after analysis and testing

Smart mobility to forge a smart city

The HKeToll system embraces smart mobility technologies such as vehicle-to-everything (V2X), IVU, 5G, and IoT. It not only facilitates the implementation of advanced network systems that monitor other road users and distant sources but also enables easier and more widespread communication among connected and automated vehicles (CAVs).