# Operational Risk Assessment of Engineering Vehicles Considering Driver Characteristics
## 2 Characterization of Drivers of Engineering Vehicles
### Analysis of Questionnaires  
The survey had 5274 validly returned questionnaires. The demographic variables of the survey include age, occupation, education level, average number of insurances in a year, average hours of sleep per day, self-reported driving style, average hours of driving per day, and driving period of the respondents. Figure 2 shows a schematic diagram of an engineering vehicle and a bus. Figure 3 shows the occupational distribution of drivers. From the total of 5274 valid data points, 3215 are drivers of engineering vehicles, accounting for 61%; 1673 are bus drivers, accounting for 32%; 281 are taxi drivers, accounting for 5%; 105 are private cars, accounting for 2%. Given that the samples of taxi and private car drivers are relatively small, the two sets of data have been merged into one group to be analyzed as \"other vehicles\". After the merger, other vehicles contains 386 drivers, accounting for 7% of the total number of drivers. As this paper mainly studies the drivers of engineering vehicles, there are nearly 15,000 drivers registered in Shenzhen, and about 8000 drivers are active all year round. A simple random sampling method was adopted for the questionnaire in the city of Shenzhen. Each driver had the same probability of being investigated [18]. The effective sample size of this paper represents one third of the city, so it is sufficiently convincing [19]. Figure 1: Structure of the questionnaire. Driving characteristics were divided into five dimensions: driving technique, driving distraction, speed control, emotional control, and driving behavior. The statistics of driving characteristic scores in each dimension are shown in Figure 4. The driving technology scores of the drivers of engineering vehicles, buses, and other vehicles show no significant difference, and the main differences can be found in speed control, driving behavior, emotional control, and driving distraction. In terms of speed control and driving behavior, drivers of engineering vehicles are slightly better than drivers of buses. Moreover, they are substantially better than drivers of other vehicles. Engineering vehicles and buses are large vehicles with certain dedicated driving paths on the road and strict speed limits. Drivers who are on duty usually undergo standardized training. They are also compliant with the traffic regulations. Thus, they have few speeding behavior problems, and their speed control is better than that of drivers of other small vehicles because engineering vehicles and buses are highly standardized. Moreover, the driving behaviors of engineering vehicle and bus drivers are better than those of other vehicle drivers. Regarding emotional regulation, engineering vehicle drivers exhibit notably superior performance compared to bus and other vehicle drivers, while bus drivers demonstrate slightly better emotional control than drivers of other vehicles. This discovery suggests that the driving demeanors of engineering vehicle drivers tend to be calmer than those of bus drivers and drivers of other vehicles. Additionally, the likelihood of experiencing \"road rage\" among the former is lower than among the latter. Figure 3: Occupational distribution. Figure 2: Schematic diagram of engineering vehicle and bus. Driving distraction shows significant variation among the three driver types, with bus drivers, engineering vehicle drivers, and drivers of other vehicles demonstrating a declining trend in performance. The initial conclusion indicates that bus drivers are the most distracted when driving their vehicles. They are followed by engineering vehicle drivers. Moreover, the performances of other vehicle drivers are poor. In summary, the characteristics of drivers of different vehicles are still different. Therefore, human factors must be added to the risk assessment of vehicles. For professional drivers, driving experience involves dealing with vehicle problems that must be considered.