Generally, large-scale accidents occurred due to unexpected interactions among multiple failures. Based on the analysis of the accident characteristics, there was a nested collection of causal factors that triggered the crash. These causes ranged from straightforward ones in the aspects of drivers or vehicles to more fundamental roots such as managerial flaws or poor safety culture in the organization.
The road transportation system is composed of several important factors like the individual, vehicle, road, environment and organization. If there are defects in these sub-systems, accidental events will be easily triggered. Combined with the accident causation theory, the key causal factors of those particularly major traffic accidents related to commercial vehicles are extracted and classified in detail.
The further analysis and discussion regarding the sub-causes under the individual, road, vehicle, goods, environment, and organization categories will be carried out in the following section.
3.2.1. Individual Factors
Through the investigation, all particularly major crashes in this study were classified as the “accountability accident”, namely human error accidents. This section has identified the individual’s unsafe acts leading to the accident and the flaws of the individual’s abilities in the aspects of the knowledge, awareness, habit, physiology and psychology that lead to the unsafe acts.
Ten categories of unsafe acts have been summarized from the accident report, as shown in Table 4
. The speeding occurred most frequently, which was one of the most direct causes of crashes. In addition, the drivers’ fatigued driving and improper operation in an emergency were also the important causes of the accident.
Almost all unsafe acts were violations of regulations, involving different frontline workers like the drivers, passengers, and dynamic supervisors for vehicles. Additionally, unsafe decisions such as the inadequate safety training and poor safety inspection organized by the management had great impacts on frontline workers’ acts, which were usually considered as the potential causes of the accident. These causal factors will be discussed as the deficiencies at the organizational level in the following section.
In Table 4
, each unsafe act was caused by two or more flaws in drivers or managers’ habitual behaviors, and the specific statistics is shown in Figure 6
. The organization should strengthen the management of individual in the aspects of training of knowledge and awareness, observation and correction of behaviors, regulation of physiological status, and intervention of psychological status.
Inadequate safety knowledge: Drivers in several accidents lacked emergency driving experience, especially when facing bad road conditions on the freeway. In addition, some drivers and management did not know the characteristics of some hazardous chemicals loaded in the vehicle and did not know how to handle the leaks after the crash.
Poor safety awareness: Some drivers were not aware of the serious consequences of speeding on the freeway and overloaded vehicles, and did not realize the risk of illegal transportation of hazardous chemicals. They failed to attach great importance on the implementation of rules or regulations regarding the traffic on the freeway.
Poor safety habits: Some drivers had developed bad driving behaviors (e.g., speeding, fatigued driving, spinning the wheel sharply, reversing casually, etc.) in their daily work. Violations of regulations appeared very frequently in the driving as accidental events did not occur in the past and the organization did not remind or punish the drivers.
Poor psychological status: Many drivers in accidents had unstable moods or bad psychology, such as the quick temper, low energy psychology (lazy, cutting corners), fluke mind, herd mentality, and some were almost not competent to do transportation work, as they were the main reason of unsafe acts in the driving.
Poor physiological status: Fatigue is considered as one of the great taboos in the driving. Many drivers in accidents were very tired and distracted after the long-time driving and had a bad emergency capacity when facing a danger on the freeway.
3.2.3. Organizational Factors
The Chinese government has attached great importance to the safety supervision of commercial vehicles, especially for the large buses and dangerous goods vehicles. The daily operation of commercial vehicles is supervised jointly by multiple organizations. Commercial vehicles must rely on an enterprise to carry out transportation activities and the organization is responsible for the dispatching, inspection and maintenance of vehicles, as well as the online supervision of drivers. In addition, the transportation enterprises must apply for a legal production safety license and accept the supervision from different government agencies (e.g., emergency management, transportation management, traffic control, etc.). Thus, the occurrence of a commercial vehicle accident was often involved in factors from multiple organizations. The safety management defect within the organization is the root cause of the accident, while the safety supervision and improper decision-making outside the organization directly affect the safety work of the enterprise, which has important indirect impacts on the accident.
Considering the directness of the enterprise’s safety management to commercial vehicles and employees, this study focuses on the analysis of the shortcomings of safety work within the organization. Based on the 24Model, the deficiencies in the construction of organizational safety management system and safety culture elements have been identified from the accident report, which can reflect the weaknesses in the safety supervision of related government agencies.
Organizational safety management determines individual behaviors [36
]. According to the statistical analysis regarding unsafe behaviors and unsafe conditions, the defects in safety management of transportation enterprises are identified or inferred, mainly involving a total of 12 system elements (see Table 6
). Common problems in organizational safety management system mainly involved the elements such as the organizational structure and personnel allocation, safety commitment or responsibility, safety education and training, identification of hidden dangers and risk assessment, etc. Procedures are of no use if they were not followed, and there was often no effective process to assess the implementation of procedures, regulations and rules in many accident organizations.
Indeed, the deficiencies in the organization’s safety policy and safety objective were not easy to be identified from the accident report, but it can be inferred that the safety policy of those accident enterprises failed to properly reflect the importance attached to safety. Although the organization may set its own safety goal, it failed to formulate effective measures to accomplish the goal. As a result, the risk identification and rectification rate, safety education and training rate, the number of emergency drills and other aspects did not meet the requirements of relevant laws and regulations.
Safety culture is considered as the guiding ideology (i.e., value, belief, vision, etc.) for the enterprise’s safety management. The weaknesses in organizational safety culture were the source of accidents, which is mainly manifested in members’ inadequate understanding and cognition for safety culture elements, thus failing to form good safety climate in the organization. Based on the above analysis of accident causation at different levels, the weaknesses in the construction of safety culture in accident organizations are identified, and five categories regarding the elements are summarized as follows:
Recognition for safety importance
The management and drivers did not attach great importance to safety, did not put safety work in the first place, did not integrate safety work into the normal management of the enterprise, and believed that safety was only input and could not produce economic benefits. Members in these business units did not reach a consensus on safety beliefs such as “safety is the first priority”, “economic benefit of safety”, “integration of safety and management”, “treatments for safety performance”.
Recognition for safety commitment
The top managers, middle management, line management and front-line operators of the enterprise failed to realize and understand their own post responsibilities, and did not well fulfill their safety responsibilities and commitments signed level by level. Members in these business units did not reach a consensus on safety beliefs such as “primary responsibility for safety”, “safety responsibility of the management”, “role of the safety department”, “responsibilities of line management departments”.
Recognition for safety management system
The organization did not realize the important influence of safety management system on individual unsafe behaviors. The members did not write the safety work into procedures in accordance with the requirement of laws and regulations, and the implementation of the systems were not completely recorded, which failed to realize the whole process management of enterprise safety including pre-prevention, in-process emergency response and post-investigation and analysis. Members in these business units did not reach a consensus on “role of safety laws and regulations”, “role of safety management system”, “emergency capability”.
Recognition for safety practice
It is meaningless if safety rules and regulations only remain on paper. The organization shall ensure the safety investment of human resources and capitals in production according to the specific requirement of laws and regulations, formulate effective execution measures regarding the procedure documents, and especially, strengthen the assessment and feedback of the implementation effect. Members in these business units did not reach a consensus on “demand of safety education and training”, “satisfaction for facilities and workplace”, “safety performance and human resources”, “types of safety inspections”.