The Taiwan Transportation Safety Board (TTSB) released the final report on the investigation of a Fang Maan tourist bus collided with the culvert of Freeway on Shueiguan Road.

At 20:23 on March 20, 2024, a commercial tourist bus operated by Fang Maan Tourist Ltd. was traveling eastbound in the slow lane of a culvert on Shueiguan Road in Renwu District, Kaohsiung City, when the upper front part of the vehicle struck the main girder of a freeway bridge. The occurrence resulted in 1 fatality, 6 occupants suffering serious injuries, 10 occupants suffering minor injuries, and damage to the vehicle body.

In accordance with the Transportation Occurrence Investigation Act, the Taiwan Transportation Safety Board (TTSB) is the independent transportation occurrence investigation agency responsible for conducting the investigation. The investigation team also included members from Ministry of Transportation and Communications (MOTC), Highway Bureau, Freeway Bureau, Transportation Bureau of Kaohsiung City Government, Public Works Bureau of Kaohsiung City Government, and Fang Maan Tourist Ltd.

The draft for this investigation report was completed in July 2025, and then, according to procedures, sent to relevant agencies (institutions) for their opinions. The investigation report was published after review and approval by the 78^th Board Meeting on September 23, 2025.

After comprehensive investigation and analysis of the factual data, a total of 10 findings and 7 safety recommendations were obtained.

1. Investigation Findings

Findings Related to Probable Causes

1. When planning his route, the occurrence driver chose to travel in the slow lane. At the intersection 60 meters before the tunnel, influenced by the 4.3-meter height limit sign on the left and the lane-division sign, he mistakenly believed that the tunnel ahead also had a 4.3-meter clearance and would allow the occurrence vehicle to pass through. In addition, the occurrence driver failed to recognize the 2.0-meter height limit sign above the culvert in time in the dim environment at night, therefore he continued driving in the slow lane. It was not until the occurrence vehicle hit the culvert that he realized the height of the vehicle exceeded the culvert height limit.

Findings Related to Risks

1. The lane width in the culvert at the site of the occurrence is only 2.2 to 2.55 meters, and the clearance height of the culvert is 2.59 meters. The roadway authority failed to set up regulatory signs limiting vehicle height within 100 meters in front of the site in accordance with the "Regulations for Road Traffic Signs, Markings and Signals", and failed to set up height limit frames or warning facilities in accordance with the "Design Standards of Urban Roads and Accessory Works". These factors made it difficult for the occurrence driver to promptly notice the height limit of the culvert ahead.
2. The Kaohsiung City Government conducted inspections and maintenance based on the existing traffic signs but did not regularly review or improve the traffic guidance system. If appropriate traffic signs were not installed during road construction, it would be difficult to detect deficiencies in the existing sign setup under the current practices.
3. Because the front section of the occurrence vehicle sustained a severe impact, the few passengers seated in the front half suffered more serious injuries. Those wearing seat belts also could not avoid the harm caused by the nature of this crash. In contrast, most passengers in the rear half sustained only minor injuries, but the number of injured was greater, primarily because they were not wearing seat belts or were standing while the vehicle was in motion.

Other Findings

1. There were no abnormalities in the tires, steering system, or braking system of the occurrence vehicle. The occurrence driver held a valid driving license issued by the Highway Bureau, and his past violations were not related to the occurrence. There was no evidence suggesting that alcohol or drugs were involved in this occurrence.
2. If a road safety inspection mechanism can be more quickly implemented on roads already in use, potential risk factors could be effectively identified and addressed early, thereby preventing similar accidents from occurring.
3. The preservation and regular updating of roadway engineering data and establishment of roadway maintenance records can illustrate the purpose of the overall road design. When implementing subsequent road improvement measures, this can facilitate the comprehensive planning of appropriate roadways and transportation projects, as well as the effective identification of roadway design issues.
4. The force exerted on the occurrence vehicle when it hit the culvert was approximately 25 to 29 metric tons. As the vehicle frame could not withstand such an excessive impact, it bent and broke, resulting in serious damage to the vehicle structure. Moreover, the locations of breaks in vehicle frame are not located at the welding points, showing no direct correlation with the welding strength of the vehicle frame.
5. Fang Maan misidentified the driver, resulting in a failure to assign the driver’s duties in accordance with regulations. Fang Maan’s documentation and management records were not accurately completed, making it impossible to effectively monitor the duty status of its drivers and vehicles. Fang Maan did not adjust its driver training programs to meet actual needs, thereby failing to achieve the intended purpose of using case studies for education and training.
6. Before the draft amendment to Article 19-4 of the Motor Vehicle Transportation Industry Management Regulations, which mandates the installation of driver identification devices, is officially promulgated, the methods used by motor vehicles supervisory authorities to conduct safety assessments remain inconsistent. Under the current practices, there is still a risk that driving hours in violation of regulations may occur without being detected.
7. Transportation Safety Recommendations

To Fang Maan Tourist Ltd.

1. Develop appropriate education and training courses based on practical needs and ensure that drivers are aware of the risks of culvert hazards.
2. Implement self-inspections of tourist bus carrier safety management and set up corresponding management data based on the contents of the self-inspection checklist to strengthen the safety management of drivers and vehicles.

To Kaohsiung City Government

1. Regularly review and improve urban road traffic guidance, including traffic signs, traffic markers, traffic signals, height restrictions, and warning systems for culverts, to ensure accuracy and completeness. When necessary, request the assistance of facility management authorities to implement improvements.
2. Conduct an inventory of data elements for various construction projects in the urban road database and complete data and drawings related to urban road engineering and traffic engineering under jurisdiction, which shall serve as the basis for roadway maintenance and formulating improvement plans.

To the Freeway Bureau, MOTC

1. Conduct an inventory of grade-separated structures involving national freeways and ordinary roads under jurisdiction. For sections of ordinary roads with a clearance height of less than 4.6 meters or a width of less than 3 meters, in addition to installing height restriction frames or warning devices within the right-of-way, it is also necessary to request the competent authority for ordinary roads to install such facilities at appropriate locations beyond the right-of-way.

To the Highway Bureau, MOTC

1. Prior to the comprehensive installation of driver identification devices, assess the frequency at which regional motor vehicle offices and motor vehicle stations, in conjunction with labor authorities, conduct safety evaluations of tourist bus carriers, or consider other temporary measures to strengthen such evaluations, so as to ensure thorough implementation of the inspection items listed in the safety assessment checklist.

To the Ministry of Transportation and Communications

1. Accelerate the introduction of Road Safety Audit (RSA) or Road Safety Inspection (RSI) mechanisms, clearly define the items and relevant standards that should be inspected at each life cycle stage of roadway traffic system projects, and implement them to comprehensively improve roadway traffic safety.

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

Ya-Ting Chang, Director

Secretariat Office

Tel: +886-2-7727-6210

E-mail: yating@ttsb.gov.tw

Frank Siao, Investigator-In-Charge

Highway Occurrence Investigation Division

Tel: +886-2-7727-6271

E-mail: frankbet@ttsb.gov.tw