RFID Controls Cargo Traffic at Hong Kong International Airport

By Bob Violino

Asia Airfreight Terminal deployed an RFID-based truck control system to monitor and manage traffic flow at two air-cargo terminals.

Asia Airfreight Terminal (AAT) operates two air-cargo terminals at Hong Kong International Airport, under a franchise awarded by the Airport Authority Hong Kong. AAT serves a number of leading airlines, offering physical cargo handling, documentation processing and other services. Revenue for a cargo terminal relies heavily on the turnover of delivered goods, so effective control of vehicles and cargo is critical. The organization's management, which is committed to investing in technology to improve customer services, deployed an RFID-based truck control system (TCS) to monitor and control traffic flow at the two terminals.

The RFID-based truck control system replaced an earlier TCS that AAT had developed and implemented in 2001 at its Terminal 1. That system employed smart-card technology, integrated with interactive voice response software (IVRS) and drop-arm barriers, to manage truck activities, allocate truck docks according to a vehicle's incoming purpose, and capture cargo delivery and collection information. Drivers swiped the smart cards as they entered and exited the terminal. The IVRS was used to verify drivers' identities and tell them the dock numbers to which they were assigned (their mobile phone numbers were registered with AAT).


When a pre-registered vehicle arrives at the terminal's entrance gate, the RFID tag is read automatically and the driver selects its incoming purpose at a kiosk located near the RFID reader at the gate.



But the solution did not optimize traffic flow in the terminal, AAT reports. The system required drivers' input, which inevitably caused problems or affected the validity of the data captured. Some drivers, for example, would forget to bring their smart cards to the terminal—and even when they had their smart cards, some would leave the truck docks without swiping them, so the system still registered the docks as occupied even though they were vacant.

When AAT decided to add a second terminal facility at the airport in 2006, the company explored alternative technologies to enhance the TCS. First, it considered using optical character recognition (OCR) systems to read vehicle-registration numbers. But OCR offered lower accuracy and at a higher cost, says Nelson Lee, AAT's general manager of corporate development.

"Ultimately, RFID could offer the best solution [for] improving the TCS," Lee says. "The technology has matured in recent years, and the low cost of each tag makes RFID a viable option. RFID's automatic identification of vehicles speeds up cargo delivery, keeps track of service standards and even enhances security, as access is only given to authorized vehicles."

How It Works


AAT hired NEC Hong Kong, based in Kowloon, to be the project's solution provider and systems integrator. AAT also set up a task force of experts from various departments, including IT, standards and procedures, and customer services, to work with NEC on the project. This team was responsible for the entire RFID implementation, including planning, developing, testing and implementing the enhanced TCS.

After a series of tests, NEC determined that a passive ultrahigh-frequency (UHF) system was the best solution for what the organization needed to accomplish. The RFID technology that AAT deployed at both terminals includes thousands of UHF tags, which operate between 920 MHz and 925 MHz, and hundreds of readers and antennas installed at entrances, exits and truck docks on multiple floors of the facilities. The system utilizes two different-size RFID tags: a small, slim tag permanently attached to the middle of the windshield on each pre-registered vehicle, and a large tag affixed by a suction cup on a single-entry vehicle; the large design was deliberate, to ensure the tag was returned at the exit gate. Both tags are ultraviolet- and heatproof, so as to withstand regular exposure to sunlight.


If parking space is unavailable, a driver is instructed to park at a waiting area until a large LED display indicates truck-dock availability.



The RFID equipment was purchased from a U.S. vendor that AAT declines to identify. The entire implementation—from proposal to equipment evaluation, installation and testing—lasted approximately 15 months.

When a pre-registered vehicle arrives at the terminal's entrance gate, the RFID tag is read automatically and the driver selects its incoming purpose at a kiosk located near the RFID reader at the entrance gate. The data captured by the interrogator, including vehicle type, license plate number and company, is passed on to a cargo-management system (CMS), which assigns the truck to the most appropriate dock available, thereby reducing wait times and optimizing cargo transfer. If parking space is unavailable, the driver is instructed to park at a waiting area until a large LED display indicates truck-dock availability. Information is also transmitted to an AAT Internet management system (AIMS) that enables customers to fully access real-time cargo acceptance and delivery information, as well as the truck-queuing situation, online.

For a single-entry vehicle, the driver must procure an entry tag at the management office, then follow the same procedure as pre-registered vehicles to find an appropriate parking area. Each truck dock is equipped with an antenna and a loop detector—a device embedded underground. When a vehicle parks in the dock, the loop detector triggers the antenna to read the tag, thereby verifying that the truck is in the assigned dock.

After loading and unloading goods, registered drivers pass through a security check and then exit the terminal. Single-entry drivers must return the RFID tag before leaving.

Overcoming Challenges


AAT and NEC faced challenges while developing and deploying the RFID-based TCS. The system had to cater to the vehicles' different heights and sizes, and technicians had to take into account several factors, such as the high ceilings of the terminals and the distance between truck docks, to ensure that the system would work smoothly for all vehicles and docks. This required multiple assessments of the terminals' infrastructure throughout the planning stages.


A small, slim tag is permanently attached to the middle of the windshield on each pre-registered vehicle.

"The RFID hardware is installed in a semi-open area, where performance can be affected when the environment changes," Lee states. Technicians spent a lot of time testing the positioning of antennas and other equipment to ensure they were receiving accurate reads, and that the data was not affected by interference.

To enhance the readability of tags and the coordination of hundreds of readers and antennas, the interrogators were designed to make the most efficient use of the available RF spectrum when large numbers of readers operate in the same area. Moreover, the readers are well shielded to handle outdoor conditions, since portions of the terminals are located outdoors.

Another challenge the companies faced was ensuring that the temporary tags would stick to vehicle windshields, and that they were located at the proper angle to be read. AAT and NEC tested the temporary tags and the suction cups on trucks of various sizes and heights, to determine the best position in which to stick the tags.

Benefits for AAT, Drivers and the Environment


Once Terminal 2 was completed, the number of truck docks AAT provided increased threefold. But thanks to the RFID-based TCS, the number of employees required to monitor traffic flow remained constant. That, the organization reports, resulted in a labor savings of about $8.5 million per year.

In addition, the RFID system improved traffic flow. AAT can now automatically assign the best truck docks to drivers in accordance with cargo storage locations. The system detects the location of trucks at different points in the terminal, which helps to identify possible bottlenecks so that management can take timely action to reduce congestion.


A large tag is affixed by a suction cup to each single-entry vehicle.

According to AAT, the average truck-queuing time in the terminals prior to implementation was 13 minutes, and the wait sometimes reached 16 minutes. With the new system, the average queuing time has dropped to less than eight minutes—a 45 percent reduction, and far lower than Hong Kong International Airport's standard of a maximum 30-minute waiting time.

Currently, Lee says, more than 95 percent of the vehicles have registered for a permanent pass. "Most drivers have found it useful to reduce waiting time" at the terminals, he states. This, he adds, has resulted in higher user satisfaction rates.

AAT "had invested time and resources in understanding the needs of its users and improving services through the enhancement of TCS," Lee says. By creating a hassle-free cargo-handling experience for terminal users, he notes, the organization provides a quicker turnaround time for drivers and a more efficient use of resources.

What's more, AAT reports, there has been a positive impact on the environment. Through the use of RFID, the organization has reduced its consumption of paper documents significantly, while also reducing the carbon emissions from vehicles waiting at the truck docks.

"The application of RFID to TCS serves as a successful role model to the logistic industry," Lee says. "By applying RFID to TCS, it reduces the necessity of manual process and manpower resources."