Vehicle Restraint Research Articles

Performance Evaluation of Vehicle Restraint Systems in the Context of Design and Installation

Vehicle Restraint Systems (VRS), a necessary component of the road design, are widely implemented by transport authorities to protect vehicles from severe incidents, mainly colliding to the roadside as well as median obstacles and other potential hazards. The performance evaluation of vehicle restraint systems at the design and installation stages is largely made according to either European or American standards. The local traffic conditions and vehicle compositions in countries, which are noticeably different from Europe and North America, necessitate a customized guideline in which the design and installation of road safety barriers are more adapted to the local conditions of the country. This paper briefly reviews the main features of EN1317, and NCHRP 350/MASH standards, which are predominantly used for the design, installation, and performance evaluation of VRS in Europe and the United States respectively. Moreover, the contribution of these standards in developing the VRS guideline for the State of Qatar is explained. The study recommends customizations to the design and installation of VRS, which are presently implemented according to the guideline developed by the Public Work Authority in Qatar. The present guideline follows European as well as American standards. The recommendations are made based on empirical studies and evidence observed by undertaking a series of site visits, audits, and perform inspections of VRS components installed on Qatari roads and highways. The study findings demonstrate the performance of VRS can be enhanced by incorporating the design and selection of road safety components such as guardrails, terminals, transitions, and crash cushions at the preliminary design stage of roads and highways. This study brings about practical insights and implications for road designers, contractors, supervision teams, and road safety auditors. Doi: 10.28991/cej-2021-03091665 Full Text: PDF

All-in-one 3D acceleration sensor based on coded liquid–metal triboelectric nanogenerator for vehicle restraint system

Vehicle restraint systems play an irreplaceable role to limit passenger injuries when an accident occurs, in which, the 3D acceleration sensor (AS) is an essential component to detect the collision position and force. However, there are some defects for commercial sensors such as passive sensing, low sensitivity and high manufacturing cost. Here, we report a lightweight, high-sensitivity, low-cost and self-powered 3D AS based on a liquid–metal triboelectric nanogenerator (LM-TENG). In view of the coded strategy of the electrodes, the 3D AS retains the smallest size, lowest weight and highest integration compared to the currently reported self-powered AS. The fabricated sensor possesses wide detection range from 0 to 100 m/s2 in the horizontal direction and 0 to 50 m/s2 in the vertical direction at a sensitivity of 800 mV/g. The open-circuit voltage shows a negligible decrease after continuously operating for 100,000 times, showing excellent stability and durability. Furthermore, the 3D AS is demonstrated as a part of the airbag system to spot the collision position and force of the car simultaneously. This work will further promote the commercialization of TENG-based sensor and exhibits a prospective application in the vehicle restraint system.

Pediatric occupant human body model kinematic and kinetic response variation to changes in seating posture in simulated frontal impacts – with and without automatic emergency braking

Objective The study quantifies the kinematics of children in booster child restraint systems (CRSs) in various naturalistic seating postures exposed to frontal impacts in a full-vehicle environment, with and without the application of pre-crash automatic emergency braking. Methods The PIPER 6YO and 10YO pediatric human body models were positioned in CRSs. The 6YO was restrained on a lowback (LBB) and highback (HBB) booster, while the 10YO was positioned on an LBB and in a NoCRS condition. All simulations used the 3-point seatbelt. The child models were pre-positioned (gravity settled, seatbelt tensioned) in four naturalistic seating postures: leaning-forward, leaning-forward-inward, leaning-forward-outward, and a pre-submarining position, along with a baseline reference seating position. A 2012 Toyota Camry finite element (FE) model was used as the vehicle environment. A standard 3-point lap-shoulder belt system was modeled to restrain the child and CRS in the left-rear vehicle seat. Two vehicle impact cases were considered: with and without a pre-crash AEB. For with-AEB cases, a pre-crash phase was run to incorporate postural changes due to the application of AEB. All seating positions were ultimately subjected to a full-frontal rigid-barrier impact at 35 MPH. A total of 40 conditions were simulated in LS-DYNA. Results Injury metrics varied widely for both occupants. Shoulder belt slippage was observed for the 6YO leaning-forward-inward on HBB. No head contact was observed for any simulated cases. Forward-leaning and forward-inward-leaning postures generally had greater head excursion across all seating postures. The lap belt rode over the pelvis for pre-submarining postures. Injury metrics for cases with pre-crash AEB were lower compared to their corresponding without-AEB cases. HIC15, head acceleration, upper neck tension force, and upper neck flexion moment were similar or lower for with-AEB scenarios. Conclusions Pre-crash AEB reduces the effect of the impact despite the same collision speed as cases without-AEB. This is primarily due to the limited travel distance of the occupant, thus, starting an earlier ride-down during the crash. Moreover, different initial seating postures lead to a wide range of injury exposures. Vehicle and child restraint design should incorporate these seating postures to ensure robust protection of the occupant in a crash.

Modeling, simulation, and validation of a TB41 crash test of the H2/W5/B concrete vehicle restraint system

The paper addresses numerical simulations of a concrete vehicle restraint system. The model is described in detail. The advanced material law of the continuous surface cap model was used to analyze the damage locations in concrete barrier segments. The results were validated against the TB41 full-scale crash test. The test was conducted in compliance with European standard EN 1317, and the validation was performed in accordance with the PD CEN/TR 16303 technical report. The force and moment envelopes of the road safety barrier during a vehicle crash are provided. The detailed concrete segment model successfully reproduced the characteristic splitting failure cracks that were found near the connection of the adjacent barrier segments in the actual structure after the full-scale crash test.

Image-based identification and GIS-integration of vehicle restraint systems and evaluation of safety effects

Image-based identification and GIS-integration of vehicle restraint systems and evaluation of safety effects

Vehicle Restraint Considerations for Commercial Spaceflight

Abstract There are currently no direct regulations and few guidelines regarding restraint design for commercial spaceflight vehicles. Operators designing vehicles intended solely for private commer...

A validation sensor based on carbon-fiber-reinforced plastic for early activation of automotive occupant restraint systems

Abstract. In the automotive industry, sensors and sensor systems are one of the most important components in upcoming challenges like highly automated and autonomous driving. Forward-looking sensors (radar, lidar and cameras) have the technical capability to already provide important (pre-)crash information, such as the position of contact, relative crash velocity and overlap (width of contact) before the crash occurs. Future safety systems can improve crash mitigation with sophisticated vehicle safety strategies based on this information. One such strategy is an early activation of restraint systems compared with conventional passive safety systems. These integrated safety systems consist of a combination of predictive forward-looking sensors and occupant restraint systems (airbags, belt tensioners, etc.) to provide the best occupant safety in inevitable crash situations. The activation of the restraint systems is the most critical decision process and requires a very robust validation system to avoid false activation. Hence, the information provided by the forward-looking sensor needs to be highly reliable. A validation sensor is required to check the plausibility of crucial information from forward-looking sensors used in integrated safety systems for safe automated and autonomous driving. This work presents a CFRP-based (carbon-fiber-reinforced plastic) validation sensor working on the principle of change in electrical resistance when a contact occurs. This sensor detects the first contact, gives information on impact position (where the contact occurs) and provides information on the overlap. The aim is to activate the vehicle restraint systems at near T0 (time of first contact). Prototypes of the sensor were manufactured in house and manually and were evaluated. At first, the sensor and its working principle were tested with a pendulum apparatus. In the next stage, the sensor was tested in a real crash test. The comparison of the signals from the CFRP-based sensor with presently used crash sensors in the vehicle highlights its advantages. The crash event can be identified at 0.1 ms after the initial contact. The sensor also provides information on impact position at 1.2 ms and enables a validation of the overlap development. Finally, a possible algorithm for the vehicle safety system using forward-looking sensors with a validation sensor is described.

The effects of vehicle restraint systems on road safety

Key to understanding the needs and tools of road infrastructure management for preventing runoff-road crashes or minimising their consequences, is to identify the hazards and sources of hazards caused by wrong or improper use of road safety devices and identify errors in the design, structure, construction and operation of road safety devices. Studying such an extended scope of the problem required fieldwork and surveys with road authorities, designers, road safety auditors and road maintenance services. An outline of new guidelines could only be developed after understanding the effects of restraint systems, the design, additional elements, type of road and safety barrier location on a road or engineering structure and the road and traffic conditions on their functionality and safety. The paper will present the preliminary results of this research (research project – ROSE). One way to understand the functionality of road safety devices is to build numerical models and conduct simulation tests of virtual crash tests. The article presents the scope of work conducted as part of an effort to develop new vehicle restraint system guidelines.

Sensitivity analysis of complex engineering systems: Approaches study and their application to vehicle restraint system crash simulation

Restricted by high calculation cost of single engineering model run and large number of model runs for sampling-based Sensitivity Analysis (SA), qualitative SA are used for parameter study of the Vehicle Restraint System (VRS) and quantitative SA of such models has always been a challenge. Sequential approaches are proposed for SA of complex systems and the SA of a VRS is realized: sampling-based SA methods are discussed; SA of a simple three points dynamic bending test model is realized, the aims are to compare different two-level screening methods and put into practice the sequential SA; crash test FE model of a VRS is created and used for SA; influential uncertain parameters of the VRS are identified qualitatively through screening analyses (SA with Two-level screening and Morris Analysis), and Sobol’ indices are used to quantify the influence of influential parameters with Kriging metamodeling. The uncertain parameters which contribute the most to robustness of the VRS are identified and their influences are quantified by combining screening analyses and Sobol’ Indices.

Optimal multiobjective design of a vehicle restraint system using pre-acting control

Purpose The purpose of this paper is to perform the limiting performance analysis of a vehicle restraint system (seat belt) in order to find the optimal control force, and its pre-acting time that minimizes the risk of injury. Design/methodology/approach A discrete model of the human thorax is used. A multiobjective optimum design problem is formulated in order to minimize the risk of injuries in case of impact. Several injury criteria are minimized and are required to remain below a safety threshold value. Findings The authors found which of the objectives are contradictory and which are not. Several of the optimal sets of design variables are analyzed and their performance compared to one another. The results are also compared to the case of not taking in account the pre-acting time. As expected, the results in this case are worse. Research limitations/implications As with all limiting performance analysis, the technological implementation restraints of the control force are not taken into account. As such, the solutions must be considered a benchmark to which the actual solution can be compared to. Practical implications The limiting performance analysis concept allows us to have a theoretical benchmark to which the real control performance can be compared to. Originality/value As far as the authors know, the pre-acting time, and its implications on the improvement of the performance of the control system, is an original contribution to the problem the authors tried to solve.

Wheel Chock Key Design Elements and Geometrical Profile for Truck Vehicle Restraint

Wheel Chock Key Design Elements and Geometrical Profile for Truck Vehicle Restraint

Pasireotide treatment does not modify hyperglycemic and corticosterone acute restraint stress responses in rats

Pasireotide is a new-generation somatostatin analog that acts through binding to multiple somatostatin receptor subtypes. Studies have shown that pasireotide induces hyperglycemia, reduces glucocorticoid secretion, alters neurotransmission, and potentially affects stress responses typically manifested as hyperglycemia and increased corticosterone secretion. This study specifically aimed to evaluate whether pasireotide treatment modifies glucose and costicosterone secretion in response to acute restraint stress. Male Holtzman rats of 150–200 g were treated with pasireotide (10 µg/kg/day) twice-daily for two weeks or vehicle for the same period. Blood samples were collected at baseline and after 5, 10, 30, and 60 min of restraint stress. The three experimental groups comprised of vehicle + restraint (VEHR), pasireotide + restraint (PASR), and pasireotide + saline (PASNR). Following pasireotide treatment, no significant differences in baseline glucose and corticosterone levels were observed among the three groups. During restraint, hyperglycemia was observed at 10 min (p < .01 for both comparisons), peaked at 30 min (p < .01 for both comparisons) and showed higher 60 min areas under glucose curves in the VEHR and PASR stressed groups when compared to the non-stressed PASNR group (p < .05 for both comparisons). Restraint also increased corticosterone secretion in the VEHR and PASR stressed groups at 5 min (p < .01 for both comparisons), and peaked at 30 min (p < .01 for both comparisons) with corresponding higher 60 min areas under corticosterone curves when compared to the non-stressed PASNR group (p < .01 for both comparisons). In conclusion, pasireotide treatment does not modify hyperglycemic- and corticosterone-restraint stress responses, thus preserving acute stress regulation.

Factors Associated With Poor Child Motor Vehicle Restraint on the USA-Mexico Border.

Motor vehicle collisions (MVCs) are a significant cause of pediatric morbidity, particularly in low- to middle-income countries. We describe car seat use in children on the USA-Mexico border. A retrospective review was conducted for children 0-9 years old, admitted to the region's only Level I trauma center. Simultaneously, data were obtained from the SAFE KIDS database, a program that encourages car seat use through city checkpoints. There were 250 MVC admissions and nine fatalities in children 0-9 years old from 2010 to 2015. Nine percent of MVCs occurred in Mexico and 49% in El Paso, TX. Comparing trauma admissions to SAFE KIDS, there was some correlation between the location of MVCs and screening checkpoints (r = .50). There was a weaker correlation between injured children's neighborhoods and screening locations (r = .32). Only 37% of parents knew the crash history of the car seat and 3% were using a car seat previously involved in an MVC. While 96% of inspected children were placed appropriately in the backseat, 80% of children were found to be inappropriately restrained. Younger children more likely to be restrained (p < .05). Children from New Mexico and Mexico had the lowest rates of proper restraint and the highest injury severity scores. Proper use of car seats is a public health concern on the USA-Mexico border, and children are not properly restrained. Screening may be improved by focusing where at-risk children live and where most accidents occur. Restraint education is needed, particularly in New Mexico and Mexico.

The vehicle frontal impact safety evaluation and design method based on the coupling effect between crash pulse and restraint system characteristic

This paper presents a new method to evaluate the design stiffness of vehicle structure and restraint system from the perspective of coupling effect, at the preliminary stage of safety design. The fast iteration algorithm is established to calculate occupant response database. Subsequently, the expressions about three indexes are derived to evaluate the crash pulse, the restraint system and the coupling effect between them. Based on the data from National Highway Traffic Safety Administration (NHTSA) frontal crash impact tests, the star-estimate map is established to estimate the star rating and design stiffness. Finally, a safety design example of M6 model is optimised to verify the validity of the proposed method, and the relative risk score (RRS) of design solution decreases by 43.6%. The proposed method can be used in the phase of conceptual design, greatly reduce the calculation amount of CAE analysis and shorten the product development cycle.

The vehicle frontal impact safety evaluation and design method based on the coupling effect between crash pulse and restraint system characteristic

This paper presents a new method to evaluate the design stiffness of vehicle structure and restraint system from the perspective of coupling effect, at the preliminary stage of safety design. The fast iteration algorithm is established to calculate occupant response database. Subsequently, the expressions about three indexes are derived to evaluate the crash pulse, the restraint system and the coupling effect between them. Based on the data from National Highway Traffic Safety Administration (NHTSA) frontal crash impact tests, the star-estimate map is established to estimate the star rating and design stiffness. Finally, a safety design example of M6 model is optimised to verify the validity of the proposed method, and the relative risk score (RRS) of design solution decreases by 43.6%. The proposed method can be used in the phase of conceptual design, greatly reduce the calculation amount of CAE analysis and shorten the product development cycle.

Analysis of the test criteria for vehicle containment systems in the Standard EN 1317 regarding the number of vehicles in use

Abstract In 1999, the harmonized standards EN 1317 relating to vehicle restraint systems came into force in Europe, in order to establish specific requirements based on safety features. For this reason, these systems have to overcome successfully the full-scale crash tests defined in these standards. However, some defined criteria are not in correspondence with the reality of Spanish roads. Almost a decade ago, in the United States, the evaluation criteria for crash tests were updated based on the new characteristics of the vehicles that circulated on their roads. Considering the registrations and fleet of light vehicles in Spain, a statistical analysis of the evolution that both parameters have undergone over the years is carried out in this paper. The outcome of this study shows, in a clear way, the change produced in the market in relation to the type of light vehicles that currently circulate in Spain.

Assessing vehicle restraint systems on horizontal curves

Horizontal curves, an element of road infrastructure, have a statistically high number of accidents. Considering that horizontal curves in the last ten years have had app. 10% of all road accidents representing app. 14% of all fatalities on Polish roads, the issue is serious and requires more research and proper road safety treatments. Data for 2007 - 2016 show that in the case of accidents on horizontal curves app. 45% of the fatalities happened as a result of crashing into roadside obstacles such as signs and first of all trees. This shows that horizontal curves require road safety equipment, and specifically, safety barriers. Key to this is using the right equipment and the right parameters. To achieve that, full-scale crash tests should be conducted to be followed by numerical tests. The article will present a synthesis of the available research conducted in Poland and abroad. An assessment will be made of four crash tests of TB32 with barriers that have a steel and cable guardrail. They are the outcome of the RID 3A “Road safety equipment” project called RoSE. Building on these tests, numerical test results will be presented.

The influence of personal protection equipment, occupant body size, and restraint system on the frontal impact responses of Hybrid III ATDs in tactical vehicles

ABSTRACTObjective: Although advanced restraint systems, such as seat belt pretensioners and load limiters, can provide improved occupant protection in crashes, such technologies are currently not utilized in military vehicles. The design and use of military vehicles presents unique challenges to occupant safety—including differences in compartment geometry and occupant clothing and gear—that make direct application of optimal civilian restraint systems to military vehicles inappropriate. For military vehicle environments, finite element (FE) modeling can be used to assess various configurations of restraint systems and determine the optimal configuration that minimizes injury risk to the occupant. The models must, however, be validated against physical tests before implementation. The objective of this study was therefore to provide the data necessary for FE model validation by conducting sled tests using anthropomorphic test devices (ATDs). A secondary objective of this test series was to examine the influence of occupant body size (5th percentile female, 50th percentile male, and 95th percentile male), military gear (helmet/vest/tactical assault panels), seat belt type (3-point and 5-point), and advanced seat belt technologies (pretensioner and load limiter) on occupant kinematics and injury risk in frontal crashes.Methods: In total, 20 frontal sled tests were conducted using a custom sled buck that was reconfigurable to represent both the driver and passenger compartments of a light tactical military vehicle. Tests were performed at a delta-V of 30 mph and a peak acceleration of 25 g. The sled tests used the Hybrid III 5th percentile female, 50th percentile male, and 95th percentile male ATDs outfitted with standard combat boots and advanced combat helmets. In some tests, the ATDs were outfitted with additional military gear, which included an improved outer tactical vest (IOTV), IOTV and squad automatic weapon (SAW) gunner with a tactical assault panel (TAP), or IOTV and rifleman with TAP. ATD kinematics and injury outcomes were determined for each test.Results: Maximum excursions were generally greater in the 95th percentile male compared to the 50th percentile male ATD and in ATDs wearing TAP compared to ATDs without TAP. Pretensioners and load limiters were effective in decreasing excursions and injury measures, even when the ATD was outfitted in military gear.Conclusions: ATD injury response and kinematics are influenced by the size of the ATD, military gear, and restraint system. This study has provided important data for validating FE models of military occupants, which can be used for design optimization of military vehicle restraint systems.

Investigation of the vehicle restraint system in a frontal impact

ABSTRACTIn this study, a comprehensive theoretical model of an in-position occupant restrained by seatbelt and airbag in an in-line frontal vehicle barrier impact is proposed. A novel approach is adopted in formulating the occupant motion based on occupant interaction with the seatbelt and airbag. Also, the airbag model developed in this paper simulates for airbag deflation both before and during occupant interaction. The proposed model is validated against test results by the system identification method through parameter optimisation. The optimisation problem is stated as a mixed integer non-linear programming problem to be solved by genetic algorithm. The results obtained with the proposed model are in good agreement with test results with a root mean square deceleration error of 0.13837 g. Furthermore, the computational time for the model has been estimated to be exceptional.

Selection of the Most Appropriate Roadside Vehicle Restraint System – The SAVeRS Project

Run Off Road (ROR) crashes are road accidents that often result in severe injuries or fatalities. To reduce the severity of ROR crashes, “forgiving roadsides” need to be designed and this includes identifying situations where there is a need for a Vehicle Restraint System (VRS) and what appropriate VRS should be selected for a specific location and traffic condition. Whilst there are standards covering testing, evaluation and classification of VRS within Europe (EN1317 parts 1 to 8), their selection, location and installation requirements are typically based upon national guidelines and standards, often produced by National Road Authorities (NRA) and/or overseeing organisations. Due to local conditions, these national guidelines vary across Europe.The European SAVeRS project, funded within the 2012 CEDR Transnational Research Programme “Safety”, has developed a practical and readily understandable VRS guidance document and a user-friendly software tool which allow designers and road administrations to select the most appropriate solution in different road and traffic conditions. This paper describes the main outcomes of the project, the process to select the most appropriate roadside barrier, and the user friendly SAVeRS tool.