Methodological analysis about the potential avoidability of motor vehicles colliding against pedestrians in urban areas

The main motivation of the authors of this article is to establish a rigorous definition of the potential capacity that a motor vehicle driver has to avoid a collision against a pedestrian. Henceforth we will call this capacity avoidability. To calculate the avoidability, it is necessary to analyze time, distance and itinerary, initial position of the pedestrian when exposed to the risk, initial speed; theoretical maximum speed developed by the vehicle and road limit speed; the driver’s reaction time and the influence of the environment; and the interrelation of the initial positions of vehicle and pedestrian with respect to the transversal axis of the road. The definition, categorized by variables, of a driver’s ability to avoid run over a pedestrian in an urban area has an evident usefulness: it allows knowing the influence of the initial speed of a vehicle as an isolated variable and the importance of the road limit speed in the ability to prevent an accident.Postprint (published version

Enabling Data-Driven Transportation Safety Improvements in Rural Alaska

Safety improvements require funding. A clear need must be demonstrated to secure funding. For transportation safety, data, especially data about past crashes, is the usual method of demonstrating need. However, in rural locations, such data is often not available, or is not in a form amenable to use in funding applications. This research aids rural entities, often federally recognized tribes and small villages acquire data needed for funding applications. Two aspects of work product are the development of a traffic counting application for an iPad or similar device, and a review of the data requirements of the major transportation funding agencies. The traffic-counting app, UAF Traffic, demonstrated its ability to count traffic and turning movements for cars and trucks, as well as ATVs, snow machines, pedestrians, bicycles, and dog sleds. The review of the major agencies demonstrated that all the likely funders would accept qualitative data and Road Safety Audits. However, quantitative data, if it was available, was helpful

An Experimental Study on Pitch Compensation in Pedestrian-Protection Systems for Collision Avoidance and Mitigation

This paper describes an improved stereovision system for the anticipated detection of car-to-pedestrian accidents. An improvement of the previous versions of the pedestrian-detection system is achieved by compensation of the camera's pitch angle, since it results in higher accuracy in the location of the ground plane and more accurate depth measurements. The system has been mounted on two different prototype cars, and several real collision-avoidance and collision-mitigation experiments have been carried out in private circuits using actors and dummies, which represents one of the main contributions of this paper. Collision avoidance is carried out by means of deceleration strategies whenever the accident is avoidable. Likewise, collision mitigation is accomplished by triggering an active hood system

Issues and challenges for pedestrian active safety systems based on real world accidents

The purpose of this study was to analyze real crashes involving pedestrians in order to evaluate the potential effectiveness of autonomous emergency braking systems (AEB) in pedestrian protection. A sample of 100 real accident cases were reconstructed providing a comprehensive set of data describing the interaction between the vehicle, the environment and the pedestrian all along the scenario of the accident. A generic AEB system based on a camera sensor for pedestrian detection was modelled in order to identify the functionality of its different attributes in the timeline of each crash scenario. These attributes were assessed to determine their impact on pedestrian safety. The influence of the detection and the activation of the AEB system were explored by varying the field of view (FOV) of the sensor and the level of deceleration. A FOV of 35 was estimated to be required to detect and react to the majority of crash scenarios. For the reaction of a system (from hazard detection to triggering the brakes), between 0.5 and 1 s appears necessary

Methodological Analysis about the Potential Avoidabilty of Motor Vehicles Colliding Against Pedestrians in Urban Areas

[EN] The main motivation of the authors of this article is to establish a rigorous definition of the potential capacity that a motor vehicle driver has to avoid a collision against a pedestrian. Henceforth we will call this capacity avoidability. To calculate the avoidability, it is necessary to analyze time, distance and itinerary, initial position of the pedestrian when exposed to the risk, initial speed; theoretical maximum speed developed by the vehicle and road limit speed; the driver’s reaction time and the influence of the environment; and the interrelation of the initial positions of vehicle and pedestrian with respect to the transversal axis of the road. The definition, categorized by variables, of a driver’s ability to avoid run over a pedestrian in an urban area has an evident usefulness: it allows knowing the influence of the initial speed of a vehicle as an isolated variable and the importance of the road limit speed in the ability to prevent an accident.Cabrerizo Sinca, J.; Campos Cacheda, J.; Perez Diez, F. (2016). Methodological Analysis about the Potential Avoidabilty of Motor Vehicles Colliding Against Pedestrians in Urban Areas. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 1614-1631. https://doi.org/10.4995/CIT2016.2015.3481OCS1614163

Motion state recognition of debris ejected in vehicular collision after contact with the ground

The motion state of debris ejected from the vehicle involved in vehicular collision is important for finding out the vehicle collision speed. This research developed an analytical model to recognise the debris motion state. With the model, analyses were conducted, which reveal that if α, which is the contact angle between the debris and the ground at the moment when the debris collides the ground, is within the range from 0° to its boundary value, then the debris slides; if α is within the range from its boundary value to 90°, then the debris bounces. With debris' initial angular velocity ω = 0, the boundary value is 11.8° for sphere debris and 7.8° for rectangular debris; with ω ≠ 0, the boundary value for rectangular debris is arcsin(g/Rω2) where g represents the acceleration due to gravity and R is the distance from the debris centre to the point of its contact with the ground. Experiment tests were conducted for debris motion states with ω = 0, which confirmed the analytical results

The Head AIS 4+ Injury Thresholds for the Elderly Vulnerable Road User Based on Detailed Accident Reconstructions

Compared with the young, the elderly (age greater than or equal to 60 years old) vulnerable road users (VRUs) face a greater risk of injury or death in a traffic accident. A contributing vulnerability is the aging processes that affect their brain structure. The purpose of this study was to investigate the injury mechanisms and establish head AIS 4+ injury tolerances for the elderly VRUs based on various head injury criteria. A total of 30 elderly VRUs accidents with detailed injury records and video information were selected and the VRUs’ kinematics and head injuries were reconstructed by combining a multi-body system model (PC-Crash and MADYMO) and the THUMS (Ver. 4.0.2) FE models. Four head kinematic-based injury predictors (linear acceleration, angular velocity, angular acceleration, and head injury criteria) and three brain tissue injury criteria (coup pressure, maximum principal strain, and cumulative strain damage measure) were studied. The correlation between injury predictors and injury risk was developed using logistical regression models for each criterion. The results show that the calculated thresholds for head injury for the kinematic criteria were lower than those reported in previous literature studies. For the brain tissue level criteria, the thresholds calculated in this study were generally similar to those of previous studies except for the coup pressure. The models had higher (>0.8) area under curve values for receiver operator characteristics, indicating good predictive power. This study could provide additional support for understanding brain injury thresholds in elderly people

Integrated protocols for accident research on the scene (OTS).

Integrated protocols for accident research on the scene (OTS)