A. Kullgren | Chalmers University of Technology (original) (raw)
Papers by A. Kullgren
THE THIRTEENTH INTERNATIONAL TECHNICAL CONFERENCE ON EXPERIMENTAL SAFETY VEHICLES, NOVEMBER 4-7, 1991, PARIS, FRANCE. VOLUME I, Jul 1, 1993
During the last years, the interest in rating the interior safety of different cars and construct... more During the last years, the interest in rating the interior safety of different cars and constructions have increased. Several methods have been used, based on either laboratory crash tests or on real life accident data. Several limitations are related to both methods, and there is no universally accepted method to rate cars in relation to each other. One technique that has been proved to be powerful in car safety rating is the paired comparison method proposed by Evans. In this method, the most important exposure parameter, accident severity, can be controlled. The method has, however, some fundamental drawback, namely that only a part of the accident population can be used. Single accidents, and accidents with trucks, buses, etcetera must be omitted. This presentation shows a technique to expand the accident data. It is also shown how aggressiveness can affect the results in safety rating, together with some other results of using paired comparisons. (A) For the covering abstract of the conference see IRRD 864606.
The risk of injury is known to be related to age. The elderly population has a far higher risk of... more The risk of injury is known to be related to age. The elderly population has a far higher risk of both serious injury and fatality, for a given severity of impact. While this is known, it is not always used for the understanding of the options for injury prevention that is available or could be developed. In the present study, the risk of in particular pedestrian injuries and fatalities were related to age. It was found, that the risk for older pedestrians is far higher than for younger, risk ratios of over 10 for the oldest age group were recorded. At the same time, the majority of fatalities for pedestrians in Sweden occurred in 50 km/h zones. In conclusion, the combination of the very high risks for elderly pedestrians and the occurrence of many of the deaths in speed zones of 50 km/h indicate that prevention techniques related to the vehicle would be very effective. Such techniques are both more friendly fronts of cars as well as emergency braking systems. At the same time, modi...
Traffic Injury Prevention, 2004
Traffic Injury Prevention, 2010
This report describes a collision force meter which comprises a simple spring-mass system. Maximu... more This report describes a collision force meter which comprises a simple spring-mass system. Maximum indication is read with the help of a string which is pulled out to maximum position and is held there. The spring and mass are enclosed in a plastic tube. The analysis showed that the meter in its present form gives a value of maximum acceleration undergone by the mass. A collision force meter without damping gives: (1) approximate values of the mean acceleration of tube up to time of maximum indication; (2) change in velocity of tube up to time of maximum indication if this is known or estimated, and (3) mean acceleration of entire collision tube, provided that maximum indication occurs after end of collision pulse. If the collision time is known or estimated, change in velocity of entire pulse is obtained. The meter gives an indication of the collision pulse experienced by the tube. The information given therefore depends on the placing of the tube. The possibility of cheaply measur...
The most important input for development and evaluation of crash protection is real life accident... more The most important input for development and evaluation of crash protection is real life accidents data. The data is however time consuming to collect. The output is in relation to what can be measured in laboratory testing, primitive. Important parameters are often collected by untrained people as secondary task in the rescue work at the accident scene. The precision and accuracy of the data can therefore often be questioned and the possibilities to draw conclusions are often limited. The possibility of collecting high quality accident data can be dramatically increased by: (1) using modern technology, such as photogrammetric measurements of exterior and interior of the vehicle deformations, cheap crash pulse recorders (CPR), and (2) training workshop and rescue personal. This presentation describes such a comprehensive system in terms of potentials and possible output, and a theoretical background for increasing precision of collected data. (A) For the covering abstract of the con...
International Journal of Crashworthiness, 2009
ABSTRACT The objective in this study of crashed cars fitted with on-board crash pulse recorders (... more ABSTRACT The objective in this study of crashed cars fitted with on-board crash pulse recorders (CPR) was to present differences in average crash severity and distribution of crash severity, depending on collision partner. The investigation included both frontal and rear-end two-vehicle and single-vehicle crashes, into deformable and rigid roadside objects. In total, 544 real-world crashes involving cars fitted with CPRs were included. A difference in average crash severity was found in crashes with different collision partners. Frontal two-vehicle and single-vehicle crashes with rigid roadside objects were shown to generate the highest crash severity. In 22% of crashes with heavy goods vehicles (HGVs) and 2% of car-to-car crashes, change of velocity exceeded 45 km/h. These differences indicate the importance of focusing on compatibility. There was a statistically significant difference between frontal two-vehicle and single-vehicle crashes with deformable objects, and also between single-vehicle crashes with deformable objects and single-vehicle crashes with rigid roadside objects. Of these, the least harmful crash type was single-vehicle crashes into deformable objects. This study provides further insight into how collision partners or objects influence change of velocity and mean acceleration in the studied vehicles. Furthermore, it illustrates the importance of paying attention to compatibility issues, regarding aspects influencing both change of velocity and acceleration.
This study set out to evaluate the effectiveness of Antilock-Brakes (ABS) on motorcycles in reduc... more This study set out to evaluate the effectiveness of Antilock-Brakes (ABS) on motorcycles in reducing real-life crashes. Since the European Parliament has voted a legislation to make ABS mandatory for all new motorcycles over 125cc from 2016, the fitment rate in the entire Europe is likely to increase in the years to come. Previous research, however, analyzed mostly large displacement motorcycles. Therefore the present study used police-reported crash data from Spain (2006-2009), Italy (2009) and Sweden (2003-2012) in an attempt to analyze a wide range of motorcycles, including scooters, and compare countries with different motorcycling habits. The statistical analysis used an induced exposure method. As shown in previous research, head-on crashes were the least ABS-affected crash type and were therefore used as non-sensitive to ABS in the calculations. The same motorcycle models, with and without ABS, were compared; the calculations were carried out for each country separately. Cras...
The introduction of automatic emergency braking changes the distribution of impact severity thus ... more The introduction of automatic emergency braking changes the distribution of impact severity thus the resulting injury risk. In the calculation of the possible safety impact, risk functions must be used. These functions can be derived in different ways. In this paper, matched pair techniques have been used to study if the power models developed by Nilsson can be used. By applying the risk functions on theoretical changes of impact speed as a result of pre impact braking, the possible effectiveness on fatal and serious injuries can be estimated. It was found, that such braking can offer major benefits. A reduction of speed before impact with 10 % can reduce fatal injuries in car crashes with approximately 30 %.
Seat belts are known to be very effective, reducing the risk of injury by approximately 50 percen... more Seat belts are known to be very effective, reducing the risk of injury by approximately 50 percent when used. Such high effectiveness is, however, based on the fact that all car occupants use the available belts. In several studies it has been shown that, in severe accidents, the seat belt use was less than 50 percent. In order to increase the wearing rate more drastic solutions than information, legislation etc have to be used. A Swedish group, representing government, research, insurance companies, and the car and restraint systems industry, has approached the problem by proposing a smart system that will force car occupants who normally are unbelted, to use the seat belts by systems that will interfere with the normal use of the car. Different technical approaches, which not in any way will interfere with the normal belt user, will be put forward and evaluated. The problem will also be discussed from a cost-effectiveness point of view and the potential of saving lives in an international perspective will be analyzed. It is shown that more than 6000 lives could be saved per year in the European Union if the existing seat belts were used.
Neck injury due to low severity vehicle crashes is of worldwide concern and it is well establishe... more Neck injury due to low severity vehicle crashes is of worldwide concern and it is well established that the risk of such injuries are higher for females than for males, even in similar crash conditions. In addition, recently developed protective systems have shown to be less protective of females than males. Hence there is a need for improved tools when developing and evaluating the performance of protective systems for occupants. The objective of this study was to develop a finite element model of a 50 th percentile female rear impact crash dummy model. The anthropometry of the 50 th percentile female was specified based on data found in the scientific published literature and is called EvaRID (Eva-female/RID-Rear Impact Dummy). EvaRID is based on the same design concept as the 50 th percentile male rear impact dummy, the BioRID. A first version, EvaRID V1.0, was developed in LS-Dyna. The dynamic response of EvaRID V1.0 was compared to data from rear impact tests with female volunteers. It was found that it is necessary to further adjust the stiffness of the joints in the spine in order to fully mimic the motion of the volunteers. In future, the EvaRID dummy model has the potential to be a valuable tool when evaluating and developing seats and whiplash protection systems.
Accident avoidance by interfence in the driver vehicle loop by changing the vehicle is a specific... more Accident avoidance by interfence in the driver vehicle loop by changing the vehicle is a specific area in the injury epidemiology field, not often studied in real life accident materials. Such factors can be ie improved handling, visibility etc. One of the most widespread safety devices in this field is Anti Locking Brakes (ABS). Such braking systems are intended to improve the manouverability of the vehicle when braking. To what extent such systems are effective is only partly known. In this study the effectiveness of ABS in the accident population is studied. By studying cars with and without ABS, but otherwise identical, it was psssible to have a control group that was not affected by vehicle characteristics other than the braking system. Accidents were subdivided into those types more or less effected by the braking system as well as on road surfaces with different friction. Not only the occurrence of the accidents were studied but also the severity.
The risk of soft tissue neck injuries as a result of rear impacts is influenced by both vehicle s... more The risk of soft tissue neck injuries as a result of rear impacts is influenced by both vehicle specific features and the impact severity of the crash. Links between real-world neck injury symptoms and dummy readings as well as neck injury criteria obtained from crash test dummies needs to establish for test methods that evaluate protection against theses injuries. This study identifies average values of neck injury criteria and dummy readings that correspond to the risk of an adult sustaining soft tissue Neck Injury Symptoms (NIS) persisting for more than one month (NIS>1). Of the real-world crashes in the Folksam database, 25 were selected according to risk levels of NIS>1 associated with mean acceleration intervals: 0% risk and 0-3 g; 0-15% risk and 3-4.5 g; 15-60% risk and 4.5-6 g. The acceleration pulses from the vehicles were reproduced in detail on a sled with a dummy in the same type of seats as in the impacted vehicles. Various levels of NIC, Nkm, forces from the uppe...
Females sustain Cervical Spine Distortion injury (CSD) more often than males. Most work dealing w... more Females sustain Cervical Spine Distortion injury (CSD) more often than males. Most work dealing with the biomechanics background (e.g. injury mechanism/criteria) as well as the application in seat design/testing, focuses on the occupant model of an average male. Therefore the EU-Project ADSEAT (Adaptive Seat to Reduce Neck Injuries for Female and Male Occupants) is aimed at adding a female model for gender balanced research of CSD and improving seat design. An extensive literature review, searching for risk factors and injury criteria for males and females, was accompanied by the evaluation of different databases containing CSD cases. The database evaluations suggests that an anthropometry quite close to the 50%ile female anthropometry as known from crash test dummy design is appropriate. The results presented here form the basis for the future development of a computational female model and the improvement of seat design for better protection of both males and females in the frame of the ADSEAT-Project.
Traffic Injury Prevention, 2006
THE THIRTEENTH INTERNATIONAL TECHNICAL CONFERENCE ON EXPERIMENTAL SAFETY VEHICLES, NOVEMBER 4-7, 1991, PARIS, FRANCE. VOLUME I, Jul 1, 1993
During the last years, the interest in rating the interior safety of different cars and construct... more During the last years, the interest in rating the interior safety of different cars and constructions have increased. Several methods have been used, based on either laboratory crash tests or on real life accident data. Several limitations are related to both methods, and there is no universally accepted method to rate cars in relation to each other. One technique that has been proved to be powerful in car safety rating is the paired comparison method proposed by Evans. In this method, the most important exposure parameter, accident severity, can be controlled. The method has, however, some fundamental drawback, namely that only a part of the accident population can be used. Single accidents, and accidents with trucks, buses, etcetera must be omitted. This presentation shows a technique to expand the accident data. It is also shown how aggressiveness can affect the results in safety rating, together with some other results of using paired comparisons. (A) For the covering abstract of the conference see IRRD 864606.
The risk of injury is known to be related to age. The elderly population has a far higher risk of... more The risk of injury is known to be related to age. The elderly population has a far higher risk of both serious injury and fatality, for a given severity of impact. While this is known, it is not always used for the understanding of the options for injury prevention that is available or could be developed. In the present study, the risk of in particular pedestrian injuries and fatalities were related to age. It was found, that the risk for older pedestrians is far higher than for younger, risk ratios of over 10 for the oldest age group were recorded. At the same time, the majority of fatalities for pedestrians in Sweden occurred in 50 km/h zones. In conclusion, the combination of the very high risks for elderly pedestrians and the occurrence of many of the deaths in speed zones of 50 km/h indicate that prevention techniques related to the vehicle would be very effective. Such techniques are both more friendly fronts of cars as well as emergency braking systems. At the same time, modi...
Traffic Injury Prevention, 2004
Traffic Injury Prevention, 2010
This report describes a collision force meter which comprises a simple spring-mass system. Maximu... more This report describes a collision force meter which comprises a simple spring-mass system. Maximum indication is read with the help of a string which is pulled out to maximum position and is held there. The spring and mass are enclosed in a plastic tube. The analysis showed that the meter in its present form gives a value of maximum acceleration undergone by the mass. A collision force meter without damping gives: (1) approximate values of the mean acceleration of tube up to time of maximum indication; (2) change in velocity of tube up to time of maximum indication if this is known or estimated, and (3) mean acceleration of entire collision tube, provided that maximum indication occurs after end of collision pulse. If the collision time is known or estimated, change in velocity of entire pulse is obtained. The meter gives an indication of the collision pulse experienced by the tube. The information given therefore depends on the placing of the tube. The possibility of cheaply measur...
The most important input for development and evaluation of crash protection is real life accident... more The most important input for development and evaluation of crash protection is real life accidents data. The data is however time consuming to collect. The output is in relation to what can be measured in laboratory testing, primitive. Important parameters are often collected by untrained people as secondary task in the rescue work at the accident scene. The precision and accuracy of the data can therefore often be questioned and the possibilities to draw conclusions are often limited. The possibility of collecting high quality accident data can be dramatically increased by: (1) using modern technology, such as photogrammetric measurements of exterior and interior of the vehicle deformations, cheap crash pulse recorders (CPR), and (2) training workshop and rescue personal. This presentation describes such a comprehensive system in terms of potentials and possible output, and a theoretical background for increasing precision of collected data. (A) For the covering abstract of the con...
International Journal of Crashworthiness, 2009
ABSTRACT The objective in this study of crashed cars fitted with on-board crash pulse recorders (... more ABSTRACT The objective in this study of crashed cars fitted with on-board crash pulse recorders (CPR) was to present differences in average crash severity and distribution of crash severity, depending on collision partner. The investigation included both frontal and rear-end two-vehicle and single-vehicle crashes, into deformable and rigid roadside objects. In total, 544 real-world crashes involving cars fitted with CPRs were included. A difference in average crash severity was found in crashes with different collision partners. Frontal two-vehicle and single-vehicle crashes with rigid roadside objects were shown to generate the highest crash severity. In 22% of crashes with heavy goods vehicles (HGVs) and 2% of car-to-car crashes, change of velocity exceeded 45 km/h. These differences indicate the importance of focusing on compatibility. There was a statistically significant difference between frontal two-vehicle and single-vehicle crashes with deformable objects, and also between single-vehicle crashes with deformable objects and single-vehicle crashes with rigid roadside objects. Of these, the least harmful crash type was single-vehicle crashes into deformable objects. This study provides further insight into how collision partners or objects influence change of velocity and mean acceleration in the studied vehicles. Furthermore, it illustrates the importance of paying attention to compatibility issues, regarding aspects influencing both change of velocity and acceleration.
This study set out to evaluate the effectiveness of Antilock-Brakes (ABS) on motorcycles in reduc... more This study set out to evaluate the effectiveness of Antilock-Brakes (ABS) on motorcycles in reducing real-life crashes. Since the European Parliament has voted a legislation to make ABS mandatory for all new motorcycles over 125cc from 2016, the fitment rate in the entire Europe is likely to increase in the years to come. Previous research, however, analyzed mostly large displacement motorcycles. Therefore the present study used police-reported crash data from Spain (2006-2009), Italy (2009) and Sweden (2003-2012) in an attempt to analyze a wide range of motorcycles, including scooters, and compare countries with different motorcycling habits. The statistical analysis used an induced exposure method. As shown in previous research, head-on crashes were the least ABS-affected crash type and were therefore used as non-sensitive to ABS in the calculations. The same motorcycle models, with and without ABS, were compared; the calculations were carried out for each country separately. Cras...
The introduction of automatic emergency braking changes the distribution of impact severity thus ... more The introduction of automatic emergency braking changes the distribution of impact severity thus the resulting injury risk. In the calculation of the possible safety impact, risk functions must be used. These functions can be derived in different ways. In this paper, matched pair techniques have been used to study if the power models developed by Nilsson can be used. By applying the risk functions on theoretical changes of impact speed as a result of pre impact braking, the possible effectiveness on fatal and serious injuries can be estimated. It was found, that such braking can offer major benefits. A reduction of speed before impact with 10 % can reduce fatal injuries in car crashes with approximately 30 %.
Seat belts are known to be very effective, reducing the risk of injury by approximately 50 percen... more Seat belts are known to be very effective, reducing the risk of injury by approximately 50 percent when used. Such high effectiveness is, however, based on the fact that all car occupants use the available belts. In several studies it has been shown that, in severe accidents, the seat belt use was less than 50 percent. In order to increase the wearing rate more drastic solutions than information, legislation etc have to be used. A Swedish group, representing government, research, insurance companies, and the car and restraint systems industry, has approached the problem by proposing a smart system that will force car occupants who normally are unbelted, to use the seat belts by systems that will interfere with the normal use of the car. Different technical approaches, which not in any way will interfere with the normal belt user, will be put forward and evaluated. The problem will also be discussed from a cost-effectiveness point of view and the potential of saving lives in an international perspective will be analyzed. It is shown that more than 6000 lives could be saved per year in the European Union if the existing seat belts were used.
Neck injury due to low severity vehicle crashes is of worldwide concern and it is well establishe... more Neck injury due to low severity vehicle crashes is of worldwide concern and it is well established that the risk of such injuries are higher for females than for males, even in similar crash conditions. In addition, recently developed protective systems have shown to be less protective of females than males. Hence there is a need for improved tools when developing and evaluating the performance of protective systems for occupants. The objective of this study was to develop a finite element model of a 50 th percentile female rear impact crash dummy model. The anthropometry of the 50 th percentile female was specified based on data found in the scientific published literature and is called EvaRID (Eva-female/RID-Rear Impact Dummy). EvaRID is based on the same design concept as the 50 th percentile male rear impact dummy, the BioRID. A first version, EvaRID V1.0, was developed in LS-Dyna. The dynamic response of EvaRID V1.0 was compared to data from rear impact tests with female volunteers. It was found that it is necessary to further adjust the stiffness of the joints in the spine in order to fully mimic the motion of the volunteers. In future, the EvaRID dummy model has the potential to be a valuable tool when evaluating and developing seats and whiplash protection systems.
Accident avoidance by interfence in the driver vehicle loop by changing the vehicle is a specific... more Accident avoidance by interfence in the driver vehicle loop by changing the vehicle is a specific area in the injury epidemiology field, not often studied in real life accident materials. Such factors can be ie improved handling, visibility etc. One of the most widespread safety devices in this field is Anti Locking Brakes (ABS). Such braking systems are intended to improve the manouverability of the vehicle when braking. To what extent such systems are effective is only partly known. In this study the effectiveness of ABS in the accident population is studied. By studying cars with and without ABS, but otherwise identical, it was psssible to have a control group that was not affected by vehicle characteristics other than the braking system. Accidents were subdivided into those types more or less effected by the braking system as well as on road surfaces with different friction. Not only the occurrence of the accidents were studied but also the severity.
The risk of soft tissue neck injuries as a result of rear impacts is influenced by both vehicle s... more The risk of soft tissue neck injuries as a result of rear impacts is influenced by both vehicle specific features and the impact severity of the crash. Links between real-world neck injury symptoms and dummy readings as well as neck injury criteria obtained from crash test dummies needs to establish for test methods that evaluate protection against theses injuries. This study identifies average values of neck injury criteria and dummy readings that correspond to the risk of an adult sustaining soft tissue Neck Injury Symptoms (NIS) persisting for more than one month (NIS>1). Of the real-world crashes in the Folksam database, 25 were selected according to risk levels of NIS>1 associated with mean acceleration intervals: 0% risk and 0-3 g; 0-15% risk and 3-4.5 g; 15-60% risk and 4.5-6 g. The acceleration pulses from the vehicles were reproduced in detail on a sled with a dummy in the same type of seats as in the impacted vehicles. Various levels of NIC, Nkm, forces from the uppe...
Females sustain Cervical Spine Distortion injury (CSD) more often than males. Most work dealing w... more Females sustain Cervical Spine Distortion injury (CSD) more often than males. Most work dealing with the biomechanics background (e.g. injury mechanism/criteria) as well as the application in seat design/testing, focuses on the occupant model of an average male. Therefore the EU-Project ADSEAT (Adaptive Seat to Reduce Neck Injuries for Female and Male Occupants) is aimed at adding a female model for gender balanced research of CSD and improving seat design. An extensive literature review, searching for risk factors and injury criteria for males and females, was accompanied by the evaluation of different databases containing CSD cases. The database evaluations suggests that an anthropometry quite close to the 50%ile female anthropometry as known from crash test dummy design is appropriate. The results presented here form the basis for the future development of a computational female model and the improvement of seat design for better protection of both males and females in the frame of the ADSEAT-Project.
Traffic Injury Prevention, 2006