Centre for Automotive Safety Research publications

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A causal model of crash test pulses: effect of impact speed on deformation and other variables
(Taylor & Francis, 2016) Hutchinson, T.
Consider crash tests in which a car strikes a solid block. Suppose there is a particular differential equation (that includes a term in deformation to the power n) relating acceleration at any instant to deformation and velocity at that moment. If that is the case, the dependencies on impact speed of maximum acceleration, duration of impact and deformation are interconnected: the relationships are power functions, and the exponents are all determined by the exponent n in the differential equation. Data from both tests and real crashes suggest that n is about 0.5 for front wheel drive cars.
Open Access
A comparison of the pedestrian passive safety performance of the new vehicle fleet in Australia, France and the United Kingdom
(Victorian Dept of Justice, 2007) Ponte, G.; Anderson, R.; Searson, D.; Australian Road Safety Research Policing and Education Conference (2007 : Melbourne, Australia); William Gibbons,; Centre for Automotive Safety Research
Improvements to frontal vehicle design can improve a pedestrian's chance of survival in a collision but there are no design rules pertaining to pedestrian protection in Australia. Some overseas regulators are mandating a minimum level of pedestrian safety, and one consequence of this might be a flow of safer designs into the Australian vehicle fleet. To assess this, the distribution of pedestrian safety performance in the new car fleet of Australia was compared to those of France and the United Kingdom. A greater proportion of new passenger vehicles rated less than 2-stars for pedestrian safety by Euro NCAP and ANCAP are sold in Australia than in France and the United Kingdom. Furthermore, the portion of the new car fleet in France and the United Kingdom assessed by Euro NCAP/ANCAP since the beginning of 2006 has shown significant improvement and has a larger proportion of better performing vehicles than the equivalent segment of the Australian new car fleet. This period corresponds with the introduction of vehicle pedestrian safety requirements in Europe.
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A computational software tool for the minimization of costs and greenhouse gas emissions associated with water distribution systems
(Elsevier, 2015) Stokes, C.; Simpson, A.; Maier, H.
Abstract not available
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A follow-up evaluation of the 50km/h Default Urban Speed Limit in South Australia
(Victorian Dept of Justice, 2007) Kloeden, C.; Woolley, J.; McLean, A.; Australian Road Safety Research Policing and Education Conference (2007 : Melbourne, Australia); William Gibbons,; Centre for Automotive Safety Research
On the 1st March 2003 the Default Urban Speed Limit (DUSL) in South Australia was lowered from 60 km/h to 50 km/h. Since this date, all urban roads have a speed limit of 50 km/h unless otherwise signed. An initial evaluation one year after the change showed that vehicle speeds and crashes had reduced on local roads with the 50 km/h limit and also on arterial roads that were signposted at 60 km/h. This paper reports the results of a follow up evaluation three years after the DUSL was introduced. Vehicles speeds were measured at the same 52 randomly chosen sites across the State. On-road speeds just before the default limit was introduced were compared with speeds measured one and three years later. Crash data was analysed by examining the crash history of all roads with a 50 km/h or 60 km/h speed limit, three years before and after the new DUSL was introduced. The study found that, on average, mean speeds had fallen by approximately 3.8 km/h on streets where the speed limit was reduced and by 2.1 km/h on arterial roads where 60 km/h speed limit signs were erected. There was a 23% reduction in casualty crashes on 50 km/h roads and a corresponding 16% reduction on 60 km/h arterial roads.
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A GPS-based examination of the mobility and exposure to risk of older drivers from rural and urban areas
(Australasian College of Road Safety, 2015) Thompson, J.; Baldock, M.; Mathias, J.; Wundersitz, L.
This study examines whether older rural drivers are restricted in their driving mobility and are exposed to more risk when driving than older urban drivers. Participants (aged >= 75 years) from rural (n = 28) and urban (n = 28) areas of South Australia were monitored using GPS devices and telephone-based travel diaries. The rural and urban participants did not differ in the number of trips that they made for discretionary or non-discretionary activities. However, while rural participants were exposed to fewer intersections (potential conflict points) in their driving than urban older drivers, they drove further and for longer periods on roads with speed limits of 100 km/h or higher, and at GPS-measured speeds of 100 km/h or faster. Therefore, they are not less mobile but have a higher exposure to road conditions that are more likely to lead to serious and fatal injuries in a crash.
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A head impact model of early axonal injury in the sheep
(MARY ANN LIEBERT INC PUBL, 1996) Lewis, S.; Finnie, J.; Blumbergs, P.; Scott, G.; Manavis, J.; Brown, C.; Reilly, P.; Jones, N.; McLean, J.
Axonal injury (AI), one of the principal determinants of clinical outcome after head injury, may evolve over several hours after injury, raising the future possibility of therapeutic intervention during this period. A new head impact model of AI in sheep was developed to examine pathological and physiological changes in the brain resulting from a graded traumatic insult. In this preliminary study 10 anesthetized and ventilated Merino ewes were used. Head injury was produced by impact from a humane stunner to the temporal region of an unrestrained head. Eight sheep were studied for 1, 2, 4, or 6 h after impact. Two sham animals (no impact, 6 h survival) were also examined. Arterial blood pressure, intracranial pressure, and cerebral blood flow were monitored continuously. A physiological index of injury severity was calculated by weighting the percentage shift from preinjury values for each monitored parameter over the first hour after injury. Immunostaining with amyloid precursor protein (APP) was used as a marker of axonal damage and the distribution of APP positive axons was recorded according to a sector scoring method (APPS). Widespread AI was identified in 7 of the 8 impacted animals, around cerebral contusions and in hemispheric white matter, central gray matter, brain stem, and cerebellum, and was detected as early as 1 h after injury. The degree of axonal injury (APPS) correlated well with an index of physiological response to injury (r = 0.83, p = 0.005).
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A method for intra-experimental validation of head impact acceleration measurements
(Elsevier, 2007) Anderson, R.; Centre for Automotive Safety Research (CASR)
Methods of measuring head kinematics during short duration impacts include the so-called 3-2-2-2 method [1]. The method uses an array of linear accelerometers to estimate linear and angular acceleration of the head. The use of these and similar arrays in PMHS and animal models can be problematic because non-rigid effects can drastically affect the measurement of angular acceleration [2]. Problems include non-rigid attachment of the array to the head. One must also consider whether or not the rigid body is actually rigid, and to what extent the surface to which the array is attached is likely to exhibit non-rigid behaviour [3]. However, if the acceleration of a rigid body is known, the acceleration at any point on the rigid body can be calculated. Therefore it is possible to quantify the validity of the acceleration measurement using the output of one or more reference accelerometers. An accelerometer placed on the skull can record the acceleration experienced by a single point on the head during the impact. The output of the array can be used to predict the acceleration of that point. The degree of correlation between the prediction of the array and the acceleration measured by the reference accelerometer provides a statistical measure of the validity of the acceleration measurement in any given impact. If the predicted and measured acceleration correlate well, one can have increased confidence that the array successfully measured the rigid body motion of the head.
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A method of constructing models of reaction to an imminent road crash
(Gale Group, 2016) Hutchinson, T.
A model for emergency reaction of a vehicle (or its driver) to an obstacle ahead helps us to understand, predict, and calculate. This paper suggests how alternative models can be constructed. the basis is specification of (1) a small number of states of the vehicle (e.g., normal driving, braking, stationary), (2) rules for transitioning between states, and (3) a dependent variable (e.g., impact speed). The rules will include one or more parameters that are characteristic of the vehicle (or driver), and which need to be estimated by testing. The models generated are intended for application in, for example, interpreting the results of testing a vehicle equipped with an AEB (autonomous emergency braking) system--in particular, in inferring what would happen in conditions (e.g., challenge distances and travelling speeds) that are not directly tested.
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A method of estimating linear and angular accelerations in head impacts to pedestrians
(PERGAMON-ELSEVIER SCIENCE LTD, 1994) Vilenius, A.; Ryan, G.; Kloeden, C.; McLean, J.; Dolinis, J.; Centre for Automotive Safety Research (CASR)
In order to investigate the relationship between impact to the head and brain injury, we have developed a method, using information obtained from reconstruction of the collisions, of estimating the peak linear and angular accelerations of the head for pedestrian impacts on a vehicle. This information includes the location of the impact on the head, the impact velocity of the head, and the stiffness of the struck surface. In developing the method we assumed that the velocity of the head on striking the vehicle was the same as the velocity of the vehicle itself, that the force vector was normal to the surface of the skull, that the force-deflection curve characterising the combined response of the impacted surfaces was linear, and that the kinetic energy of the head immediately prior to impact was converted into strain energy in deforming the head and the vehicle structure. Only the loading phase of the impact was considered, there was no assumption of an elastic unloading phase. Using cadavers, the validity of these assumptions and hence the usefulness of the method were tested by comparing the estimates of peak linear acceleration with the results of 18 pedestrian-vehicle impact reconstructions. On average, the method underestimated the experimental values by about 15%, with a range of +/- 35%. The results from the application of this method are currently being used to study the relationship between the magnitude and direction of the impact to the head and the distribution and severity of the brain injury resulting from actual collisions.
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A model for determining injury risk on the basis of impact speed
(IRCOBI, 2014) Gockowiak, K.; Anderson, R.; Searson, D.; International Research Council on the Biomechanics of Injury (IRCOBI) (10 Sep 2014 - 12 Sep 2014 : Berlin, Germany)
This paper discusses a model that estimates the effect of a change in impact velocity on vehicle impact response. The motivation of the study is to develop a model that will be able to predict occupant injury risk over a range of speeds based on performance in standard crash tests. The model comprises a tipped equivalent square wave (TESW) acceleration pulse to model the vehicle acceleration that is dependent on impact speed. The model was used to analyse data from five full‐width rigid‐barrier impact testing carried out at five speeds. Analyses were selected to investigate the relationship between impact speed, vehicle dynamic crush and mean impact acceleration. The results suggest that it is possible to model vehicle impact response (specifically the magnitude of dynamic crush and mean vehicle impact acceleration) using a bi‐linear, impactvelocity‐ dependent relationship, based on a limited number of crash tests. Models such as these may provide a means of integrating assessment of vehicle crashworthiness with the assessment of primary safety technologies designed to reduce the speed of crashes.
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A new strategy is an opportunity for leadership
(Australasian College of Road Safety, 2009) Lydon, M.
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A notation for the structure of cognitive processes, with application to patterns of verb-processing impairment
(Psychology Press, 2003) Hutchinson, T.
A method is proposed for processing datasets that show whether or not each of several patients was impaired on each of several tests, and expressing conclusions about them. Its advantages are that (1) results from the patterns of impairment alone are shown, uninfluenced by theories, previous empirical work, knowledge of lesions, or ideas about what the tests are really testing, and (2) the presentation to the reader is briefer and clearer than a narrative account. The method is applied to data on the patterns of impairment of 30 subjects on six tests, each requiring the processing of verbs (Kemmerer et al., Language and Cognitive Processes , 2001). A new interpretation of this dataset is given, in terms of a set of three systems, all of which are essential. These systems resemble three of those that Kemmerer et al. hypothesised that the six tests might utilise.
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A Possible Explanation of Statistical Interaction, With Application to the Effects of Soluble Thrombomodulin and Soluble Intercellular Adhesion Molecule-1 on Coronary Heart Disease
(Lippincott Williams & Wilkins, 2003) Hutchinson, T.
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A robust estimation of the effects of motorcycle autonomous emergency braking (MAEB) based on in-depth crashes in Australia
(Taylor & Francis, 2016) Savino, G.; Mackenzie, J.; Allen, T.; Baldock, M.; Brown, J.; Fitzharris, M.
Autonomous emergency braking (AEB) is a safety system that detects imminent forward collisions and reacts by slowing down the host vehicle without any action from the driver. AEB effectiveness in avoiding and mitigating real-world crashes has recently been demonstrated. Research suggests that a translation of AEB to powered 2-wheelers could also be beneficial. Previous studies have estimated the effects of a motorcycle AEB system (MAEB) via computer simulations. Though effects of MAEB were computed for motorcycle crashes derived from in-depth crash investigation, there may be some inaccuracies due to limitations of postcrash investigation (e.g., inaccuracies in preimpact velocity of the motorcycle). Furthermore, ideal MAEB technology was assumed, which may lead to overestimation of the benefits. This study sought to evaluate the sensitivity of the simulations to variations in reconstructed crash cases and the capacity of the MAEB system in order to provide a more robust estimation of MAEB effects.First, a comprehensive classification of accidents was used to identify scenarios in which MAEB was likely to apply, and representative crash cases from those available for this study were populated for each crash scenario. Second, 100 variant cases were generated by randomly varying a set of simulation parameters with given normal distributions around the baseline values. Variants reflected uncertainties in the original data. Third, the effects of MAEB were estimated in terms of the difference in the impact speed of the host motorcycle with and without the system via computer simulations of each variant case. Simulations were repeated assuming both an idealized and a realistic MAEB system. For each crash case, the results in the baseline case and in the variants were compared. A total of 36 crash cases representing 11 common crash scenarios were selected from 3 Australian in-depth data sets: 12 cases from New South Wales, 13 cases from Victoria, and 11 cases from South Australia.The reduction in impact speed elicited by MAEB in the baseline cases ranged from 2.8 to 10.0 km/h. The baseline cases over- or underestimated the mean impact speed reduction of the variant cases by up to 20%. Constraints imposed by simulating more realistic capabilities for an MAEB system produced a decrease in the estimated impact speed reduction of up to 14% (mean 5%) compared to an idealized system.The small difference between the baseline and variant case results demonstrates that the potential effects of MAEB computed from the cases described in in-depth crash reports are typically a good approximation, despite limitations of postcrash investigation. Furthermore, given that MAEB intervenes very close to the point of impact, limitations of the currently available technologies were not found to have a dramatic influence on the effects of the system.
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Accelerations relevant to blunt trauma: theory and data
(National Institute of Occupational Safety and Health, 2015) Hutchinson, T.P.
Maximum acceleration and the Head Injury Criterion (HIC) are both used as indicators of likely head injury severity. A dataset has previously been published of impacts of an instrumented missile on four ground surfaces having a layer of between 0 and 16 cm of sand. The dataset is compared with recently-developed theory that predicts power-function dependence of maximum acceleration and HIC on drop height. That prediction was supported by the data. The surfaces differed in respect of the exponents estimated.
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Adult pedal cycle casualties in South Australia
(Institution of Engineers, Australia, 2007) Hutchinson, T.; Kloeden, C.; Long, A.; Centre for Automotive Safety Research (CASR)
Characteristics of adult cyclist casualties (as reported to the police) in South Australia, and how they have changed over the period 1981-2004, are examined. In 1981, pedal cyclist casualties were mostly children and teenagers. In 2004, pedal cyclist casualties were mostly spread across the age range from 16 to 49. Adult pedal cyclist casualties reached a maximum in 1987-1990, and then fell. The main sets of results in the present paper are grouped as the crash site and events, the motor vehicle and its driver, and other factors (including the pedal cyclist). There is also discussion of sources of accident data other than the police, and of speed limit reduction and cyclists sharing paths with pedestrians as accident prevention measures.
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Age, sex and blood alcohol concentration of killed and injured drivers, riders and passengers
(PERGAMON-ELSEVIER SCIENCE LTD, 1994) Holubowycz, O.; Kloeden, C.; McLean, J.; Centre for Automotive Safety Research (CASR)
The relationships between type of road user, sex, age, and blood alcohol concentration (BAC) were examined among 1,389 adult vehicle occupants and motorcyclists fatally injured in crashes within South Australia from 1985 to 1992, inclusive, and among 1,573 adult vehicle occupants and motorcyclists admitted to a Level-1 trauma centre from August 1985 to July 1987. The relationships between BAC and both day of week of crash and the number of vehicles involved were determined among fatalities, whereas among admissions, duration of hospitalization and type of unit to which the casualty was admitted were also examined. BACs of .08 g/100 mL or higher were found in 38% of killed and 30% of injured drivers, 37% and 27% of passengers, and 35% and 22% of male motorcycle riders. Alcohol involvement was almost nonexistent among the elderly. The finding that the proportion of injured motorcyclists was similar to that of drivers is consistent with motorcyclists' increased risk of injury even in relatively minor crashes. Male motorcycle riders were found to be significantly younger than male drivers. They were also significantly less likely to have been drinking and, if they had been drinking, their mean BAC was significantly lower. The results are also consistent with the well-established observations that alcohol involvement is greater in single-vehicle crashes and in crashes occurring on weekends. Average duration of hospitalization was not found to differ between types of road user or between those with a BAC above and below .08 g/100 mL.
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Age, sex and blood alcohol concentration of killed and injured pedestrians.
(1995) Holubowycz, Oksana T.
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Age-based selection of child restraints
(Australasian College of Road Safety, 2012) Anderson, R.; Hutchinson, T.
BACKGROUND: Advice to parents about child restraints is sometimes based on the child’s weight, and can be complicated and confusing. Children tend to want to progress to the next restraint earlier rather than later, and the lack of clarity in advice to parents means that parents are more likely to move children up into the next type of restraint prematurely. Moreover, many parents do not know the weight of their child. This paper explores what might be the consequences of very simple advice, such as advising parents to change the type of restraint when children reach 6 months of age, 4 years, and 8 years. METHOD: The distribution of children’s weights at different ages is used, along with the range of weights for which each restraint is appropriate, to work out the number of children who would be in an inappropriate restraint if progression were at particular ages. RESULTS: If 6 months is the age of transition from an infant capsule to a forward-facing child restraint, the number of children misclassified is approximately two one-month cohorts. If 48 months is the age of transition from a forward-facing child restraint to a booster seat, the number of children misclassified is again approximately two one-month cohorts. CONCLUSION: These numbers of misclassifications are low (relative to what has been reported in surveys when weight-based advice was the norm). It has not been proven that there would indeed be good compliance with sharp ages of transition, but the simplicity and salience of age make it attractive as a criterion.
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Agreement between experts: an answer, but is it the answer for you?
(Churchill Livingstone, 2003) Hutchinson, T.
The question of how should agreement between experts be measured, when their opinions are expressed on an ordinal scale, is discussed. The example used is that of quality of articles submitted to Journal of Clinical Neuroscience. Polychoric correlation is a useful concept, and there are now computer programs available to estimate this. However, it is also emphasised that the definition of agreement is a matter of choice, and the choice should be made carefully: even error-free measurements should not automatically be assumed to possess all the properties of numbers, and ordinal categories bring further difficulties.

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