| 1. |
- Abraham, Nikil, et al.
(author)
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Assessment of the impact speed and angle conditions for the EN1317 barrier tests
- 2016
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In: International Journal of Crashworthiness. - : Informa UK Limited. - 1358-8265 .- 1754-2111. ; 21:3, s. 211-221
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Journal article (peer-reviewed)abstract
- ABSTRACT: Roadside safety barriers designs are tested with passenger cars in Europe using standard EN1317 in which the impact angle for normal, high and very high containment level tests is 20°. In comparison to EN1317, the US standard MASH has higher impact angles for cars and pickups (25°) and different vehicle masses. Studies in Europe (RISER) and the US have shown values for the 90th percentile impact angle of 30°–34°. Thus, the limited evidence available suggests that the 20° angle applied in EN 1317 may be too low. The first goal of this paper is to use the US NCHRP database (Project NCHRP 17–22) to assess the distribution of impact angle and collision speed in recent ROR accidents. Second, based on the findings of the statistical analysis and on analysis of impact angles and speeds in the literature, an LS-DYNA finite element analysis was carried out to evaluate the normal containment level of concrete barriers in non-standard collisions. The FE model was validated against a crash test of a portable concrete barrier carried out at the UK Transport Research Laboratory (TRL). The accident data analysis for run-off road accidents indicates that a substantial proportion of accidents have an impact angle in excess of 20°. The baseline LS-DYNA model showed good comparison with experimental acceleration severity index (ASI) data and the parametric analysis indicates a very significant influence of impact angle on ASI. Accordingly, a review of European run-off road accidents and the configuration of EN 1317 should be performed.
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| 2. |
- Appleyard, Bob, et al.
(author)
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Best Practice Guideline: Transportation of People Seated in Wheelchairs, Version 2.21.
- 2010
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In: [Host publication title missing].
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Conference paper (peer-reviewed)abstract
- Summary, key points: Transport considerations ought to be factored into the initial phase of the wheelchair & seating assessment process. Manufacturers of wheelchairs and seating systems should make information relating to the safe transportation of their products readily available - and easy to understand. With the desire to provide the safest possible transport environment for wheelchair-seated passengers, and other vehicle occupants, all stakeholders must engage in a multi-disciplinary approach to ensuring transport safety; involving the wheelchair user with their families, carers, equipment prescribers, and transport providers*. A proven crashworthy wheelchair, used in conjunction with a proven wheelchair tie-down and occupant restraint system (WTORS), is fundamental to the provision of safe transport for both people who remain seated in their wheelchairs in a motor vehicle and other vehicle occupants. Exceptions exist on certain high-mass, low-speed urban public transport vehicles, where the likelihood of a crash situation and the severity thereof are low. Powered and manual wheelchairs offer a large variety of seated postures through their tilt, recline, and other mechanisms. Guidelines ought to be given by manufacturers with respect to use of these mechanisms during transport. The combination of a crashworthy seating system, that accommodates the proper fit of the occupant restraints, and a crashworthy wheelchair serve to indicate to the prescriber that the risks of equipment failure when exposed to crash conditions during transport have been reduced as far as reasonably possible. To minimise injury risk for wheelchair occupants, prescribers shall seek to ensure that the means of attachment of the seating system to the wheelchair is suitable for use in transport. It is imperative that the manufacturer’s instructions for use and fitting instructions for seating systems are carefully adhered to. Due to the individual nature of disability, prescribers may at times be faced with the need to work beyond manufacturers’ recommendations for the use of systems in order to maximise medical benefits, and to address the postural and functional needs of a wheelchair user. In such cases a risk management process ought to be followed, and transport providers should have a working comprehension of the relevant documented risk assessment process and understand the subsequent Risk/Benefit analysis. When properly used, a WTORS allows the wheelchair to be well secured to the vehicle floor and the passenger in the wheelchair to benefit from a properly fitted seatbelt system. Wheelchair manufacturers should highlight in their pre-sale literature any special requirements relating to the use of their wheelchair with WTORS. This information should include the configuration of the representative wheelchair, which was subjected to crash testing, so that informed decisions can be made with respect to wheelchair selection & configuration. Prescriber awareness of the type of transport environment and the facilities available to assist vehicle entry and egress is highly beneficial in the risk analysis process.
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| 3. |
- Gildea, Kevin, et al.
(author)
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Computer vision-based assessment of cyclist-tram track interactions for predictive modeling of crossing success
- 2023
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In: Journal of Safety Research. - 0022-4375. ; 87, s. 202-216
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Journal article (peer-reviewed)abstract
- Introduction: Single Bicycle Brashes (SBCs) are common, and underreported in official statistics. In urban environments, light rail tram tracks are a frequent factor, however, they have not yet been the subject of engineering analysis. Method: This study employs video-based analysis at nine Dublin city centre locations and introduces a predictive model for crossing success on tram tracks, utilising cyclist crossing angles within a Surrogate Measure of Safety (SMoS) framework. Additionally, Convolutional Neural Networks (CNNs) were explored for automatic estimation of crossing angles. Results: Modelling results indicate that cyclist crossing angle is a strong predictor of crossing success, and that cyclist velocity is not. Findings also highlight the prevalence of external factors which limit crossing angles for cyclists. In particular, kerbs are a common factor, along with passing/approaching vehicles or other cyclists. Furthermore, results indicate that further training on a relatively small sample of 100 domain-specific examples can achieve substantial accuracy improvements for cyclist detection (from 0.31AP0.5 to 0.98AP0.5) and crossing angle inference from traffic camera footage. Conclusions: Ensuring safe crossing angles is important for cyclist safety around tram tracks. Infrastructural planners should aim for intuitive, self-explainable road layouts that allow for and encourage crossing angles of 60° or more – ideally 90°. Practical Applications: The SMoS framework and the open-source SafeCross1 application offer actionable insights and tools for enhancing cyclist safety around tram tracks.
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| 4. |
- Gildea, Kevin, et al.
(author)
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Forward dynamics computational modelling of a cyclist fall with the inclusion of protective response using deep learning-based human pose estimation
- 2024
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In: Journal of Biomechanics. - 0021-9290. ; 163
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Journal article (peer-reviewed)abstract
- Single bicycle crashes, i.e., falls and impacts not involving a collision with another road user, are a significantly underestimated road safety problem. The motions and behaviours of falling people, or fall kinematics, are often investigated in the injury biomechanics research field. Understanding the mechanics of a fall can help researchers develop better protective gear and safety measures to reduce the risk of injury. However, little is known about cyclist fall kinematics or dynamics. Therefore, in this study, a video analysis of cyclist falls is performed to investigate common kinematic forms and impact patterns. Furthermore, a pipeline involving deep learning-based human pose estimation and inverse kinematics optimisation is created for extracting human motion from real-world footage of falls to initialise forward dynamics computational human body models. A bracing active response is then optimised for using a genetic algorithm. This is then applied to a case study of a cyclist fall. The kinematic forms characterised in this study can be used to inform initial conditions for computational modelling and injury estimation in cyclist falls. Findings indicate that protective response is an important consideration in fall kinematics and dynamics, and should be included in computational modelling. Furthermore, the novel reconstruction pipeline proposed here can be applied more broadly for traumatic injury biomechanics tasks. The tool developed in this study is available at https://kevgildea.github.io/KinePose/kevgildea.github.io/KinePose/.
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| 5. |
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| 6. |
- Li, G., et al.
(author)
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A virtual test system representing the distribution of pedestrian impact configurations for future vehicle front-end optimization
- 2016
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In: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 17:5, s. 515-523
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Journal article (peer-reviewed)abstract
- Objectives: The purpose of this study is to define a computationally efficient virtual test system (VTS) to assess the aggressivity of vehicle front-end designs to pedestrians considering the distribution of pedestrian impact configurations for future vehicle front-end optimization. The VTS should represent real-world impact configurations in terms of the distribution of vehicle impact speeds, pedestrian walking speeds, pedestrian gait, and pedestrian height. The distribution of injuries as a function of body region, vehicle impact speed, and pedestrian size produced using this VTS should match the distribution of injuries observed in the accident data. The VTS should have the predictive ability to distinguish the aggressivity of different vehicle front-end designs to pedestrians.Methods: The proposed VTS includes 2 parts: a simulation test sample (STS) and an injury weighting system (IWS). The STS was defined based on MADYMO multibody vehicle to pedestrian impact simulations accounting for the range of vehicle impact speeds, pedestrian heights, pedestrian gait, and walking speed to represent real world impact configurations using the Pedestrian Crash Data Study (PCDS) and anthropometric data. In total 1,300 impact configurations were accounted for in the STS. Three vehicle shapes were then tested using the STS. The IWS was developed to weight the predicted injuries in the STS using the estimated proportion of each impact configuration in the PCDS accident data. A weighted injury number (WIN) was defined as the resulting output of the VTS. The WIN is the weighted number of average Abbreviated Injury Scale (AIS) 2+ injuries recorded per impact simulation in the STS. Then the predictive capability of the VTS was evaluated by comparing the distributions of AIS 2+ injuries to different pedestrian body regions and heights, as well as vehicle types and impact speeds, with that from the PCDS database. Further, a parametric analysis was performed with the VTS to assess the sensitivity of the injury predictions to changes in vehicle shape (type) and stiffness to establish the potential for using the VTS for future vehicle front-end optimization.Results: An STS of 1,300 multibody simulations and an IWS based on the distribution of impact speed, pedestrian height, gait stance, and walking speed is broadly capable of predicting the distribution of pedestrian injuries observed in the PCDS database when the same vehicle type distribution as the accident data is employed. The sensitivity study shows significant variations in the WIN when either vehicle type or stiffness is altered.Conclusions: Injury predictions derived from the VTS give a good representation of the distribution of injuries observed in the PCDS and distinguishing ability on the aggressivity of vehicle front-end designs to pedestrians. The VTS can be considered as an effective approach for assessing pedestrian safety performance of vehicle front-end designs at the generalized level. However, the absolute injury number is substantially underpredicted by the VTS, and this needs further development.
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| 7. |
- Li, G., et al.
(author)
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Can a small number of pedestrian impact scenarios represent the range of real-world pedestrian injuries?
- 2016
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In: 2016 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury. ; , s. 20-34
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Conference paper (peer-reviewed)abstract
- The purpose of this study is to evaluate the predictive capability of a virtual test system (VTS) proposed for vehicle front assessment of pedestrian injury risk. The VTS accounts for a broad range of impact scenarios in pedestrian accidents and the assessment is done using recent pedestrian accident data. Firstly, simulation test samples (STS) accounting for the broad range of vehicle impact speed pedestrian height and gait stance in real world impact scenarios were developed based on different sets of multibody vehicle-to-pedestrian impact simulations. Then a sedan and a van model were tested using the defined STSs. The AIS2+ injuries predicted from these STSs for each vehicle model were weighted by the involving proportion of each impact scenario observed from German In-Depth Accident Study (GIDAS) pedestrian accident data via a defined Injury Weighting System (IWS). The injury predictive capability of the VTSs using different STS sample sizes and the corresponding IWS was evaluated by comparing the predicted AIS 2+ injury rate and distribution of AIS 2+ injuries as a function of pedestrian body region and height, vehicle class and impact speed with that observed from the GIDAS data. The results indicate that the proposed VTS using a STS of about 120 cases is broadly capable of predicting the AIS 2+ injury rate and distribution of pedestrian AIS 2+ injuries observed from the real-world accidents when the same vehicle class distribution as the accident data is employed. The VTS can be considered as an effective approach for assessing pedestrian safety performance of vehicle front designs at the generalised level.
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| 8. |
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| 9. |
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| 10. |
- Li, G., et al.
(author)
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Safer passenger car front shapes for pedestrians: A computational approach to reduce overall pedestrian injury risk in realistic impact scenarios
- 2017
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In: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575. ; 100, s. 97-110
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Journal article (peer-reviewed)abstract
- Vehicle front shape has a significant influence on pedestrian injuries and the optimal design for overall pedestrian protection remains an elusive goal, especially considering the variability of vehicle-to-pedestrian accident scenarios. Therefore this study aims to develop and evaluate an efficient framework for vehicle front shape optimization for pedestrian protection accounting for the broad range of real world impact scenarios and their distributions in recent accident data. Firstly, a framework for vehicle front shape optimization for pedestrian protection was developed based on coupling of multi-body simulations and a genetic algorithm. This framework was then applied for optimizing passenger car front shape for pedestrian protection, and its predictions were evaluated using accident data and kinematic analyses. The results indicate that the optimization shows a good convergence and predictions of the optimization framework are corroborated when compared to the available accident data, and the optimization framework can distinguish ‘good’ and ‘poor’ vehicle front shapes for pedestrian safety. Thus, it is feasible and reliable to use the optimization framework for vehicle front shape optimization for reducing overall pedestrian injury risk. The results also show the importance of considering the broad range of impact scenarios in vehicle front shape optimization. A safe passenger car for overall pedestrian protection should have a wide and flat bumper (covering pedestrians’ legs from the lower leg up to the shaft of the upper leg with generally even contacts), a bonnet leading edge height around 750 mm, a short bonnet ( 17° or
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