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Candefjord S.,Chalmers University of Technology | Candefjord S.,Sahlgrenska University Hospital | Candefjord S.,Vehicle and Traffic Safety Center at Chalmers | Winges J.,Chalmers University of Technology | And 5 more authors.
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS | Year: 2013

Traumatic brain injury (TBI) is a major public health problem worldwide. Intracranial bleedings represents the most serious complication of TBI and need to be surgically evacuated promptly to save lives and mitigate injury. Microwave technology (MWT) is promising as a complement to computed tomography (CT) to be used in road and air ambulances for early detection of intracranial bleedings. In this study, we perform numerical simulations to investigate if a classification algorithm based on singular value decomposition can distinguish between bleedings at different positions adjacent to the skull bone for a similar but simplified problem. The classification accuracy is 94-100% for all classes, a result that encourages us to pursue our efforts with MWT for more realistic scenarios. This indicates that MWT has potential for localizing a detected bleeding, which would increase the diagnostic value of this technique. © 2013 IEEE. Source

Strand N.,Vehicle and Traffic Safety Center at Chalmers | Strand N.,Swedish Road and Transport Research Institute | Nilsson J.,Vehicle and Traffic Safety Center at Chalmers | Nilsson J.,SP Technical Research Institute of Sweden | And 4 more authors.
IET Intelligent Transport Systems | Year: 2011

This study explores end-user experiences of adaptive cruise control (ACC) systems. A qualitative approach has been applied and data have been collected by means of focus group interviews. A qualitative content analysis was carried out to analyse and interpret collected data. In total the study consists of three focus group sessions with five to seven participants in each. Themes explored include interaction between user and system, functional limitations and trust, and system effects on driving behaviour. Key findings include reported driving behaviour changes as, for instance, an increasing tendency to stay in the right lane as well as users'conception of system functionality from which it can be concluded that end-users of ACC carry rough mental models of the system. A potentially hazardous situation for other road-users following the use of ACC is highlighted and discussed. In addition, some features desired by the end-users are discussed, for example, the call for conventional cruise control functionality when owing to weather conditions functional limitations are apparent. © 2011 The Institution of Engineering and Technology. Source

Strand N.,Vehicle and Traffic Safety Center at Chalmers | Strand N.,Swedish Road and Transport Research Institute | Nilsson J.,Vehicle and Traffic Safety Center at Chalmers | Nilsson J.,SP Technical Research Institute of Sweden | And 4 more authors.
Transportation Research Part F: Traffic Psychology and Behaviour | Year: 2014

The purpose of this study was to examine the effects of vehicle automation and automation failures on driving performance. Previous studies have revealed problems with driving performance in situations with automation failures and attributed this to drivers being out-of-the-loop. It was therefore hypothesized that driving performance is safer with lower than with higher levels of automation. Furthermore, it was hypothesized that driving performance would be affected by the extent of the automation failure. A moving base driving simulator was used. The design contained semi-automated and highly automated driving combined with complete, severe, and moderate deceleration failures. In total the study involved 36 participants. The results indicate that driving performance degrades when the level of automation increases. Furthermore, it is indicated that car drivers are worse at handling complete than partial deceleration failures. © 2014 Elsevier Ltd. All rights reserved. Source

Wagstrom L.,Volvo Car Corporation | Wagstrom L.,Chalmers University of Technology | Wagstrom L.,Vehicle and Traffic Safety Center at Chalmers | Kling A.,Volvo Car Corporation | And 4 more authors.
International Journal of Crashworthiness | Year: 2013

There has been significant development in passenger car crashworthiness over the last few decades. However, real-world crashes often occur in scenarios dissimilar to laboratory barrier crash set-ups. Further knowledge is required on how different impact scenarios affect vehicle structural response and occupant injury risk in real-world scenarios. This study introduces a methodology for assessing crash configuration parameters that influence the structural response in car-to-car frontal collisions by using finite element models of two identical vehicles. The crash configuration parameters included in this study were initial velocities, oblique angle and lateral offset distance. An evaluation was made in terms of passenger compartment intrusion and crash pulse severity. Special focus was directed towards investigating whether these input parameters can be used to define incompatible scenarios, i.e. where the structural response in one vehicle is significantly different compared to the other vehicle. Results indicate that collision scenarios with large overlap as extreme in terms of crash pulse severity, and incompatible car-to-car crash scenarios were found at small overlap and an oblique angle of 15°. An outlook for future model and method validation work is described. © 2013 Taylor and Francis Group, LLC. Source

Candefjord S.,Chalmers University of Technology | Candefjord S.,Vehicle and Traffic Safety Center at Chalmers | Candefjord S.,Sahlgrenska University Hospital | Buendia R.,Chalmers University of Technology | And 11 more authors.
Traffic Injury Prevention | Year: 2015

Objective: The aim of this study is to develop an on-scene injury severity prediction (OSISP) algorithm for truck occupants using only accident characteristics that are feasible to assess at the scene of the accident. The purpose of developing this algorithm is to use it as a basis for a field triage tool used in traffic accidents involving trucks. In addition, the model can be valuable for recognizing important factors for improving triage protocols used in Sweden and possibly in other countries with similar traffic environments and prehospital procedures. Methods: The scope is adult truck occupants involved in traffic accidents on Swedish public roads registered in the Swedish Traffic Accident Data Acquisition (STRADA) database for calendar years 2003 to 2013. STRADA contains information reported by the police and medical data on injured road users treated at emergency hospitals. Using data from STRADA, 2 OSISP multivariate logistic regression models for deriving the probability of severe injury (defined here as having an Injury Severity Score [ISS] > 15) were implemented for light and heavy trucks; that is, trucks with weight up to 3,500 kg and ⩾ 16,500 kg, respectively. A 10-fold cross-validation procedure was used to estimate the performance of the OSISP algorithm in terms of the area under the receiver operating characteristic curve (AUC). Results: The rate of belt use was low, especially for heavy truck occupants. The OSISP models developed for light and heavy trucks achieved cross-validation AUC of 0.81 and 0.74, respectively. The AUC values obtained when the models were evaluated on all data without cross-validation were 0.87 for both light and heavy trucks. The difference in the AUC values with and without use of cross-validation indicates overfitting of the model, which may be a consequence of relatively small data sets. Belt use stands out as the most valuable predictor in both types of trucks; accident type and age are important predictors for light trucks. Conclusions: The OSISP models achieve good discriminating capability for light truck occupants and a reasonable performance for heavy truck occupants. The prediction accuracy may be increased by acquiring more data. Belt use was the strongest predictor of severe injury for both light and heavy truck occupants. There is a need for behavior-based safety programs and/or other means to encourage truck occupants to always wear a seat belt. © 2015, Copyright © Taylor & Francis Group, LLC. Source

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