A dynamic tire model based on HPSO-SVM

Due to the randomness and weak symmetry of traffic accidents occurring in the expressway maintenance operation area, it is difficult to use the number of traffic accidents to evaluate the safety of maintenance operation areas. In this paper, the traffic characteristics and traffic conflicts of the maintenance operation area with the lane closed on the outside of the two-way four-lane expressway are studied. By using the statistical method, the distribution of vehicle speed and time headway in different areas of the maintenance operation area are analyzed, and the queuing characteristics of vehicles in the upstream transition zone of the expressway are determined. Based on improved time to collision (TTC) model, the traffic conflict severity of expressway maintenance operation area is divided. The negative binomial distribution is used to establish a traffic conflict prediction model for the enclosed maintenance area of the outer lane of the expressway, and the validity of the traffic conflict prediction model is verified based on the average absolute error percentage (MAPE). The research results show that: when the 0 < TTC < 1.3 s, the traffic conflict is serious conflict; when 1.3 s < TTC, the traffic conflict is non-serious conflict. Furthermore, the traffic conflict prediction model has high accuracy, the MAPE of the warning area and the upstream transition area are 10.8% and 5.0%, respectively.

This research is conducted on the characters and trends of traffic flow in highway maintenance work areas under typical maintenance work forms. In order to improve the safety of the highway maintenance work area, a data monitoring method based on the combination of mixed speed measurement and background difference method were developed. During the on-site detection, the starting point of the warning zone, the starting point of the upstream transition zone, the starting point of the working zone, the midpoint of the working zone, and the six speed measurement sections of the working zone were collected at the end point and the end zone. In the video detection, the background subtraction was used, and the morphological denoting method and the connected domain analysis method were used to retain the vehicle foreground. After analyzing the connection domain and removing the wrong target, the vehicle target area is extracted from research. The research finally obtained the traffic flow characteristics of the start point of the warning zone, the start point of the upstream transition zone, the start point of the work zone, the midpoint of the work zone, the end point of the work zone, and the end point of the downstream transition zone. The study also obtained the traffic volume and the change trend of headway. The combination of mixed velocity method and background difference method is helpful for data monitoring in typical highway maintenance work areas. The measured data results are helpful for studying the distribution characteristics and trends of traffic flow in typical highway maintenance work areas.

An advanced automatic crash notification (AACN) system can predict the injuries of a vehicle's occupants when the vehicle is involved in a collision accident. The rear‐seat occupants are at significant risk in collision accidents owing to an inferior protection system and the absence of mandatory seat belt laws. However, only a few studies have focused on the injury prediction for rear‐seat occupants, which can be used in AACN system. Therefore, an injury prediction algorithm is proposed for rear‐seat occupants. Initially, a rear‐seat occupant simulation model is established and verified and the relationship between the head, neck, and chest injury levels and velocity variation is examined. Then, a rear‐seat occupant injury prediction algorithm is developed and AACN terminal is constructed to analyse the effects of the algorithm. The comparison of the obtained results with actual accident data validated that the proposed algorithm can effectively evaluate the injury levels of rear‐seat occupants. The study findings can enhance the prediction accuracy of all occupants’ injury levels based on their positions inside the vehicle and improve the efficiency of rescue operations, particularly in the case of rear‐seat occupants.

Efficiency and notification accuracy are two critical criteria for evaluating the performance of automatic crash notification (ACN) systems. The discrimination threshold (DT) is used to assess whether a collision accident occurs. Typically, the DT value is determined based on the maximal acceleration peak from multiple road tests. Because an overlarge DT value is unnecessary in most driving scenes and simultaneously adversely affects notification accuracy, a crash recognition (CR) algorithm with adaptive DT is proposed. First, a road–vehicle simulation model is constructed using the CarSim software. Next, the vehicle acceleration data at different driving speeds are obtained based on this road–vehicle model. Subsequently, a correlation model comprising a discrimination threshold value, an international roughness index, and the vehicle speed is developed. Finally, a CR algorithm is designed, in which discrimination threshold values that match the road roughness and vehicle speed are specified. Road and collision tests show that the proposed algorithm can identify collisions and calculate the speed change value more accurately compared with the conventional CR algorithm which has a fixed discrimination threshold.

With the continuous development of vehicle intelligence technology and active safety technology, the autonomous emergency braking pedestrian (AEB-P) system has emerged as a crucial element of contemporary automotive active safety systems. However, there are still some deficiencies in the control strategies utilized by the current AEB-P system. It is imperative to design an AEB-P system that can adapt the safety threshold and control strategy in real time based on the current driving conditions. The objective of this paper is to propose an AEB-P system with an adaptive control strategy and analyse its effectiveness from the perspective of pedestrian head injuries. Initially, an algorithm for adaptive collision time threshold model is proposed, and the AEB-P control strategy integrating this threshold is designed. Subsequently, a finite element model of the human head is developed to predict pedestrian head injuries in pedestrian-vehicle collision (PVC) scenarios with AEB-P intervention. Additionally, a simplified finite element model of PVC is established, and real PVC scenarios are reconstructed to assess the effectiveness of various AEB-P control strategies in mitigating pedestrian head injuries. The results demonstrate that the conventional control strategy is ineffective in reducing the risk of pedestrian head injuries at medium to high speeds. Conversely, the AEB-P system, which incorporates an adaptive control strategy, proves to be effective in decreasing the risk of pedestrian head injuries. Overall, the AEB-P system with adaptive control strategy enhances pedestrian safety, particularly in scenarios where PVCs are inevitable.