Yunnan Provincial Department of Transportation

Objectives Taxis play a crucial role in urban transportation systems, and increased ride-hailing services have further solidified their importance. However, traffic safety issues concerning taxis remain insufficiently addressed. This study investigates the effect of key occupational factors, including demographic characteristics, financial burdens, driver fatigue and risky driving behavior, on traffic crashes involving both traditional and ride-hailing taxi drivers. Methods Given the potential differences between the two groups, which could lead to distinct causes of crashes, a comparative evaluation was conducted. Data were collected through self-reported surveys, involving 2039 traditional taxi drivers and 2181 ride-hailing taxi drivers. Six hypotheses were proposed to examine the relationships between these occupational factors and crash risks, with particular attention to demographic differences. Two structural equation models were employed to test the hypotheses. Results Significant differences were observed between the two groups. For traditional taxi drivers, traffic violations were the most significant factor directly influencing crash risk, whereas for ride-hailing taxi drivers, employment status played the most substantial role. Conclusion These findings provide valuable insights for policymakers, highlighting the need for differentiated interventions such as regulating entry qualifications, strengthening fatigue management and establishing reward systems for safe driving to reduce crash risks among distinct driver groups.

Abstract Existing highway emergency personnel allocation patterns exhibit imbalances in the workload of emergency personnel on some road sections. On certain road sections with low traffic volumes and minimal toll revenue, the operational costs for emergency personnel are excessively high. Therefore, an efficient and economical method is required for the allocation of highway emergency personnel to respond to complex and dynamic highway emergencies. We established an optimization model for emergency personnel allocation based on an improved emperor penguin optimization (EPO) algorithm. First, the model introduces assumptions regarding the resource consumption of highway emergency tasks, guaranteed task operation time and sequential order of task execution by emergency personnel. The highway emergency personnel allocation problem is described mathematically. The optimization objectives of the model include minimizing the weighted processing time of emergency events, maximizing the workload balance and minimizing deployment costs. Constraints on emergency resource allocation are also defined. We propose an improved EPO algorithm that focuses on the initialization and optimization stages, improving parameter configuration, position updating, iterative convergence and disaster evaluation. Data from a traffic management office in Kunming, China were used for case analysis. We focused on the relationship between emergency events and the locations of emergency protection sites. We also examined the allocation of resources for traffic and natural disasters. Additionally, the resource deployment costs before and after optimization were compared. The results demonstrate that the proposed model reduces the cost of resource allocation by 30.6% and greatly improves the optimization of highway emergency staffing.

To solve the problems of inefficiency, manual dependence, and subjectivity of traditional tunnel lining crack detection techniques, as well as the limitations of high cost and difficulty in popularization of high-end technologies such as ultrasonic and radar detection, this paper proposes a tunnel lining crack detection method based on Android cell phones. Deep learning techniques are utilized to obtain the optimal weight file by training the YOLOv5s detection model, and subsequently, the weight file is converted to NCNN format for Android devices. Application software was developed with the help of the Android Studio tool to realize the deployment and application of the tunnel lining crack detection model on Android phones. The inspector takes an image through the cell phone’s camera function and selects the crack image from the cell phone album to start the crack recognition function based on the CPU or GPU driver with one click, which provides an efficient and economical solution for tunnel maintenance and safety management.

<p indent="0mm">By studying the variations of bearing capacity characteristics of two bored piles before and after being grouted, the radius of the plastic influential zone of cement pastes after being compactedly grouted at pile ends was derived by Vesic’s theory. A single pile model and pile group models considering different quantities of piles, pile spacing, and grouting conditions were respectively constructed, in which the pile spacing was 2 to 6-times pile diameters for 2×2 pile groups and 3-times pile diameters for 3×3 pile groups. Then, the effect of grouting at pile ends on settlement, pile end resistance, pile side resistance, and ratios of pile end resistance and total resistance were studied. The conclusions were that the grouting bearing capacity efficiency for pile group foundations dropped with an increase in pile quantities in the same pile space. The order of the bearing capacity of 2×2 pile group foundations from large to small was the foundation with pile space of 5-, 6-, 4-, and 3-times pile diameters. When the pile spacing was 5-times pile diameters, the bonding effect of expanding heads of pile ends and pile group effect were maximized. In the same working condition, the ratio of end resistance and total resistance was significantly enhanced after being grouted, while in the same quantity of piles, the ratio of end resistance and total resistance dropped gradually with an increase in pile space. When the pile space was smaller, the end resistance of piles increased more apparently than the side friction resistance of piles. As the ferrule effect by side piles, corner piles and surrounding soil on middle piles in settlement processes of pile foundations, lateral friction resistance of corner piles and side piles worked earlier than that of middle piles. The order of lateral friction resistance from large to small was that of corner piles, side piles and middle piles.