The Taiwan Transportation Safety Board (TTSB) released the final report on the investigation of a Kuo-Kuang Motor Transportation Inter-City Bus Collided with a Roadside Wall at the Bus Area Exit of Terminal 1 of Taoyuan International Airport.

     On May 16, 2025, at approximately 01:35, an intercity bus operated by Kuo-Kuang Motor Transportation Company Ltd. (hereinafter referred to as “Kuo-Kuang” and the “occurrence vehicle,” respectively) collided with a roadside wall while turning near the bus area exit of Terminal 1 at Taoyuan International Airport. As a result of the collision, 32 occupants on board sustained injuries.

     In accordance with the Transportation Occurrences Investigation Act, the TTSB is the independent transportation occurrence investigation agency responsible for conducting the investigation. The investigation team also included members from the Highway Bureau, Ministry of Transportation and Communications (MOTC); Taoyuan International Airport Corporation Ltd.; and Kuo-Kuang Motor Transportation Company Ltd.

     The draft investigation report was completed in July 2026, and then, according to procedures, sent to relevant agencies (institutions) for their opinions. The investigation report was published after review and approval by the 88^th Board Meeting on July 21, 2026.

     After comprehensive investigation and analysis of the factual data, a total of 10 findings and 6 safety recommendations were obtained.

Ⅰ.Investigation Findings

Findings Related to Probable Causes

1. After departing from the parking bay at the platform, the occurrence driver repeatedly raised and waved his right hand while speaking to passengers as the occurrence vehicle was in motion. As a result, he failed to pay attention to the road ahead and continued traveling straight at the turn. In addition, his alertness and concentration may have declined as the duration of his wakefulness and on-duty hours increased. The occurrence driver was also unfamiliar with the performance and correct operation of the braking system. He relied primarily on the auxiliary brake and did not apply the service brake to decelerate until 1.1 seconds before the collision. Consequently, the occurrence vehicle was unable to stop in time and collided with the wall adjacent to the exit ramp of the bus area.

Findings Related to Risks

1. Kuo-Kuang’s periodic training for drivers did not provide sufficient coverage of safe driving practices and vehicle system functions, and did not arrange all drivers to participate in the training. Furthermore, Kuo-Kuang did not adopt proactive management measures for drivers with repeated violations or a high risk for accidents, making it difficult to effectively correct unsafe driving behaviors.
2. Kuo-Kuang’s scheduling arrangements created conditions in which driver fatigue could accumulate. Drivers were also required to perform administrative or vehicle maintenance tasks during the intervals between services, further reducing their rest time and impairing their ability to remain fit and alert for extended duty.
3. Based on the geometric conditions of the entrance and exit ramps at the bus area of Terminal 1 of Taoyuan International Airport, the ramps can only meet the standards prescribed for a design speed of 25 km/h under the Specification of the Highway Route Design. However, the current speed limit on the ramps is 50 km/h, and there is a lack of supplementary guidance signs provided at the curves. These conditions directly affect the ease of steering and the operating safety of large vehicles.

Other Findings

1. This occurrence was not directly related to the driver's past violations. There is no evidence that alcohol or drugs were involved in this occurrence. The occurrence driver had a valid license issued by the Highway Bureau, MOTC. No abnormalities were found in the tires, steering system, or braking system of the occurrence vehicle.
2. On-site measurements at the occurrence location showed that the illuminance at the driver’s eye position inside the vehicle was below the maximum recommended light-exposure value of 25 lux specified in the Ministry of Environment’s Light Pollution Guidelines for discomfort caused by artificial-light trespass into indoor environments. In addition, other drivers involved in the subjective assessment reported no discomfort from the ambient lighting or illumination on the wall and were able to clearly identify the surrounding environment.
3. The occurrence vehicle was carrying 32 people, and 32 people were injured after the occurrence, including 4 serious injuries, representing 12.5% of injuries. The occurrence driver and 27 passengers sustained minor injuries, representing 87.5%. The seriously injured passengers primarily sustained nasal bone fractures, while the minor injuries mainly consisted of abrasions and contusions to the head and limbs.
4. The occurrence driver did not wear his seat belt after departing from Terminal 1 of Taoyuan Airport. The driver’s seat belt was secured with a strap and was loose. The belt surface was also damaged, with fraying and wear along its edges. However, these conditions were not identified during Kuo-Kuang’s safety inspections or periodic inspections of the occurrence vehicle, thereby reducing the seat belt’s protective capabilities for the driver.
5. The occurrence driver reminded passengers to fasten their seat belts in Chinese. However, foreign-language content was limited on the vehicle’s interior labels, stickers, and passenger information system, and no foreign-language announcements were provided on board. This was not conducive to effectively reminding foreign passengers to fasten their seat belts.
6. The Chinese characters on the emergency exit sign for the left rear emergency door of the occurrence vehicle did not meet the regulatory requirement of each character measuring at least 10 cm by 10 cm. This may have reduced the visibility and recognizability of the emergency exit sign.

Ⅱ.Safety Recommendations

To Kuo-Kuang Motor Transportation Company Ltd.

1. Strengthen driver management methods to effectively correct unsafe driving behaviors. In addition, ensure that periodic training or practical vehicle-operation courses are conducted every six months so that drivers acquire the correct operating skills and knowledge of braking systems.
2. Review driver scheduling and duty planning to give drivers sufficient time to rest and appropriately reduce drivers’ non-driving work to reduce the chance of fatigue accumulation.
3. Strengthen management mechanisms to ensure that drivers correctly use seat belts while driving and that seat belt conditions are inspected. Ensure that drivers are effectively protected by seat belts when driving.
4. For international airport bus services, increase audio and written reminders in foreign languages instructing passengers to fasten their seat belts. In addition, review the emergency exit signs on all vehicles to ensure that their specifications comply with regulatory requirements and are able to meet the identifiability requirements in an emergency.

To the Highway Bureau, MOTC

1. Supervise Kuo-Kuang Motor Transportation Company Ltd.

(1) Strengthen management measures for high-risk drivers, ensure that drivers participate in periodic training, and ensure that they possess the correct operating skills and knowledge of braking systems.

(2) Review the suitability of the driver scheduling and duty planning to reduce the risk of driver fatigue.

(3) Strengthen the management mechanisms for ensuring that drivers properly use seat belts while driving and inspecting seat belts, so as to ensure that drivers are effectively protected by seat belts when driving.

(4) Promote the implementation of audio and written reminders in foreign languages instructing passengers to fasten their seat belts on international airport bus services, and ensure that vehicle emergency exit signs comply with regulatory requirements.

To Taoyuan International Airport Corporation Ltd.

1. Review the geometric conditions of the roads within the bus areas at each terminal in accordance with the applicable provisions of the Specification of the Highway Route Design. Adjust the speed limits and install appropriate traffic control devices accordingly to improve the safety of buses turning on roads within the bus areas.

Full Final Report in Chinese is available for download at https://www.ttsb.gov.tw

Eric Shen, Director

Secretary Office

Tel: +886-2-7727-6229

E-mail: ericshen@ttsb.gov.tw

Frank Siao, Investigator-In-Charge

Highway Occurrence Investigation Division

Tel: +886-2-7727-6271

E-mail: frankbet@ttsb.gov.tw