COLLISION

Transition is a type of barrier that connects other barriers with different grades and shapes. Even if each barrier satisfies the performance, it may not be satisfied in transition. Therefore, collision safety requires a special design and examination. In this study, we investigated national and foreign standards and situations for the proper configuration of the transition and analyzed the impact behavior of the general transition using impact simulations. We developed a transition system that could ensure the stable performance of various grades by analyzing the behavior and confirmed based on the full-scale crash test (SB2 level).

A physically representative bird modeling approach is presented to highlight its significance over traditional substitute bird modeling. To give better representation of a real bird, in this study, the bird was modeled as a fluid body while impacting the rigid and deformable structures. For this, an elastic plastic hydrodynamic material model in conjunction with polynomial equation of state is utilized to model the bird behavior. In addition, smoothed particle hydrodynamics (SPH)-based meshless technique was implemented to build real bird model instead of using finite element-based classical mesh technique in order to avoid mesh connectivity and tangling problems. The numerical scheme was validated by comparing the deformation and pressure profile of the impact on rigid and deformable targets with the available experimental data. The results showed that the physically representative bird impacting the rigid and deformable target give correct values of pressure peak than that of subs...

The aim of the present research was to investigate whether individuals with a common cold showed impaired ability on a simulated driving task and the ability to detect potential collisions between moving objects. The study involved comparison of a healthy group with a group with colds. These scores were adjusted for individual differences by collecting further data when both groups were healthy and using these scores as covariates. On both occasions, volunteers rated their symptoms and carried out a simulated driving session. On the first occasion, volunteers also carried out a collision detection task. University of Leeds Institute for Transport Studies. Twenty-five students from the University of Leeds. Ten volunteers were healthy on both occasions and 15 had a cold on the first session and were healthy on the second. In the collision detection task, the main outcomes were correct detections and response to a secondary identification task. In the simulated driving task, the outcom...

Passing collisions are one of the most serious traffic safety problems on two-lane highways. The purpose of this dissertation is to develop a framework for a passing collision warning system (PCWS) for two-lane highways that can help drivers avoid passing collisions by reducing the chance of human error. Specifically, the objectives of this research are: (1) to conduct a comprehensive literature review of existing collision warning systems, (2) to design driving simulator and field experiments for data collection, (3) to develop deterministic and reliability-based models for passing sight distance (PSD) that consider driver characteristics, (4) to develop an in-vehicle passing collision warning system, and (5) to develop a Simulink model that implements the proposed PCWS in a real time environment. A driving simulator was used to collect data from participants (males and females of different ages). The field study data werecollected on real highways using an in-vehicle video camera ...

Passing collisions are one of the most serious traffic safety problems on two-lane highways. These collisions occur when a driver overestimates the available sight distance. This paper presents a framework for a passing collision warning system (PCWS) that assists drivers in avoiding passing collisions by reducing the likelihood of human error. The system uses a combination of a camera and radar sensors to identify the impeding vehicle type and to detect the opposing vehicles traveling in the left lane. The study involved the development of a steering control model providing lane-change maneuvers, the design of a driving simulator experiment that allows for the collection of data necessary to estimate passing parameters, and the elaboration of the algorithm for the PCWS based on sensor signals to detect impeding vehicles such as trucks. Simulation tests were carried out to confirm the effectiveness of the proposed PCWS algorithm. The impact of driver behavior on passing maneuvers wa...

Modern vehicles are equipped with various sensors of high accuracy and sensitivity, based on which it is possible to implement passing collision warning systems (PCWS) for two-lane highways. In previous systems, the time required to complete the passing maneuver safely was formulated based on pre-established regression models. In this paper, this time is formulated based on actual vehicle characteristics. The new vehicle dynamics model for the PCWS prototype includes steering control and drivetrain models, and allows more accurate prediction of the required passing time. The geometry of the passing maneuver (for the case of an impeding truck), the main phases of the passing process, and the distances related to the conditions for predicting passing time are described. The interactions between the PCWS and driver actions are formulated. The steering control model is based on a two-dimensional perspective representation of the three-dimensional reality perceived by the driver. The dri...

We present a momentum conserving hybrid particle/grid iteration for resolving volumetric elastic collision. Our hybrid method uses implicit time stepping with a Lagrangian finite element discretization of the volumetric elastic material together with impulse-based collision-correcting momentum updates designed to exactly conserve linear and angular momentum. We use a two-step process for collisions: first we use a novel grid-based approach that leverages the favorable collision resolution properties of Particle-In-Cell (PIC) techniques, then we finalize with a classical collision impulse strategy utilizing continuous collision detection. Our PIC approach uses Affine-Particle-In-Cell momentum transfers as collision preventing impulses together with novel perfectly momentum conserving boundary resampling and downsampling operators that prevent artifacts in portions of the boundary where the grid resolution is of disparate resolution. We combine this with a momentum conserving augury i...

Estimating the probability of failures or accidents with aerospace systems is often necessary when new concepts or designs are introduced, as it is being done for Autonomous Aircraft. If the design is safe, as it is supposed to be, accident cases are very rare. This feature requires some variance reduction technique in the probability estimation and several algorithms exist for that, however some specific model features may cause difficulties in practice, such as the case of system models where independent agents have to autonomously accomplish missions within finite time, and likely with the presence of human agents. For handling these scenarios, this paper presents a novel estimation approach, based on the combination of the well-established variation reduction technique of Interacting Particles System (IPS) with the long-standing optimization algorithm denominated DIviding RECTangles (DIRECT). When combined, these two techniques yield statistically significant results for extreme...

Accidents involving vehicles crashing into reinforced retaining walls are increasing because of the increased construction of reinforced retaining walls on roads. Unlike a normal retaining wall, a reinforced retaining wall is not one united body but is made up of blocks. Hence, a reinforced wall can break down when a vehicle crashes into it. The behavior of such a wall during vehicle collision depends upon the reinforcement material used for its construction, its design, and the method of the construction. In this study, the behavior of a reinforced retaining wall was analyzed while changing the reinforcement spacing using LS-DYNA, a general finite-element program. Eight tons of truck weight was used for the numerical analysis model. The behavior of a reinforced retaining wall under variable reinforcement spacing and positioning was analyzed. The results indicated that the reinforcement material was an important resistance factor against external collision load.