A cross-sectional study of the prevalence of medical conditions as contributors to road crashes in South Australia.

OBJECTIVES: With the population of Australians aged 85 or older expected to double by 2042 and the association of increased age with the greater likelihood of having medical conditions, the potential for an increase in the number crashes caused by medical conditions is of concern. This study aims to understand the prevalence of medical conditions contributing to road crashes and the characteristics of these crashes, in order to guide development of strategies to mitigate the risks and harms involved. METHOD: The sample consisted of 1,934 active road users (drivers, motorcyclists, cyclists, pedestrians) injured in crashes on South Australian roads who were admitted to the Royal Adelaide Hospital over the period 2014 to 2017. RESULTS: The findings indicate that 9.2% of hospital admission cases were directly caused by a medical condition or acute medical event, with loss of consciousness, attempted suicide, and seizures the most commonly observed. Crashes attributed to a medical condition were more likely to involve older drivers and those with a greater number of preexisting medical conditions. CONCLUSION: Medical conditions or acute medical events are a significant contributor to road crashes. Common crash types involving medical conditions or events - single vehicle, hit object - indicate that vehicle technologies such as lane keeping assist and autonomous emergency braking, and infrastructure treatments such as roadside barriers, may help to prevent crashes in which a driver experiences a medical event. Monitoring of drivers with medical conditions should continue, while the benefits of social policies that reduce reliance on private motor vehicles for transport should also be explored.

Entrapment and extraction of wheelchairs at flange gaps with and without flange gap fillers at pedestrian railway crossings.

PURPOSE: Where pedestrian crossings meet rail tracks, a flange gap allows the train wheel flanges to pass. This gap can be hazardous for wheelchair users as castor wheels may become trapped. While compressible gap fillers can eliminate the flange gap, fillers are subject to wear, pose a derailment hazard to light rail vehicles and can strip grease from passing wheels. These issues could be mitigated by partially filling the flange gap with a compressible filler. The aim was to investigate the risk of entrapment and ease of extraction of wheelchair castors from flange gaps fully and partially filled with compressible fillers, and assess ride quality. MATERIALS AND METHODS: Entrapment risk and ease of extraction for four wheelchairs were tested at various crossing angles with flange gap fillers. Twelve wheelchair users tested ease of extraction and ride quality for partially and fully filled flange gaps. RESULTS: It was found that risk of entrapment is low if a standards-compliant crossing with open flange gaps is traversed in a straight line. However, castors can become trapped if the user alters direction to avoid an obstacle or if the crossing surface is uneven. Once trapped, castors are extremely difficult to remove without external assistance. CONCLUSIONS: Flange gap fillers that reduce the gap to 10 mm or less eliminate entrapment while retaining acceptable ride quality. Filling flange gaps or leaving a residual gap depth of less than 10 mm is the best option to eliminate risk of entrapment and ensure good ride quality for wheelchair users.IMPLICATIONS FOR REHABILITATIONRail crossings flange gaps pose an entrapment hazard for wheelchair usersPartial or complete flange gap fillers may reduce entrapment but require researchRehabilitation professionals need to educate wheelchair users on techniques to cross flange gaps safelyConsumers and health professionals can consult rail operators to partially fill flange gaps.

Seat belt injuries and external markings at autopsy in cases of lethal vehicle crashes.

A study was undertaken to determine what injuries are associated with the wearing of seat belts and if the presence of cutaneous seat belt markings observed on victims of lethal vehicle crashes increased the likelihood of underlying injury. Autopsy reports from the files at Forensic Science South Australia were reviewed for all fatal motor vehicle crashes from January 2014 to December 2018. A total of 173 cases were included for analysis with 127 occupants wearing seat belts at the time of impact (73.4%) (age range = 18-93; mean = 45 M:F = 81:46). Of these, only 38 had external seat belt markings (29.9%) (age range = 19-83; mean = 49 M:F = 20:18). Logistic regression modelling showed that occupants who were wearing seat belts were more likely to experience closed head injury without skull fractures in addition to mesenteric and gastrointestinal injury. Increasing body mass index increased the incidence of seat belt markings (p < 0.01) and markings were more likely to be found in the presence of bilateral pelvic fractures. Thus, external seat belt markings were observed in only a minority of seatbelt wearers, and more often in individuals with higher BMIs and with bilateral pelvic fractures (possibly associated with greater momentum and impact force).

An overview of suicides related to motor vehicles.

Although vehicles may be used in a wide variety of suicides, this has not been a focus in the forensic literature. Thus, an analysis of coronial autopsy reports at Forensic Science SA, Adelaide, South Australia over a 16-year period from January 2005 to December 2020 was undertaken to provide an overview of cases in which it was considered that a vehicle had been integral to the successful completion of a suicide. De-identified details were collected from all cases in which a vehicle had facilitated or been used as a method of suicide. A number of different types of vehicle-related suicide methods were identified, including cases where vehicles had been used as secure places for suicide or where the vehicle had been used to cause significant blunt force trauma or to enter a lethal environment such as water. Specific examples were taken from the following categories: (1) inhalation of gas, (2) drug toxicity, (3) hanging or ligature strangulation, (4) self-immolation, (5) drowning, (6) vehicle collision, (7) driving off a cliff, (8) jumping or lying in front of a vehicle and (9) the use of more than one method (i.e. complex). This report is not intended to provide an epidemiological analysis of car-related suicides. Instead, the details of selected cases have been used to illustrate the spectrum of methods that may be used in vehicle-assisted suicides.

The effect of age on injury patterns in pedestrian deaths.

Although it is known that elderly pedestrians are at increased risk of injury and death from vehicle crashes the specific pattern of lethal injuries related to age has not been extensively studied. Data on the numbers of pedestrian fatalities and ages were obtained from 1990 to 2020 from the Traffic Accident Reporting System, The University of Adelaide, Adelaide, South Australia and detailed autopsy data on fatal pedestrian crashes from the pathology database at Forensic Science SA, Adelaide, South Australia from 2000 to 2020. Fatal injuries were separated into the following regions: head/face, spine, chest, abdomen and limbs/skeleton. Analysis of 634 cases of pedestrian fatalities (1990-2020) showed a significant decline in numbers over the years (p < 0.001). Analysis of fatal injuries in 219 cases (2000-2020) showed a significant reduction in the proportion of fatal head injuries with increasing age (p < 0.05), a significant increase in the proportion of fatal chest injuries with increasing age (p < 0.01) and a significant increase in the proportion of fatal limb/skeletal injuries with increasing age (p < 0.05). Older pedestrians are, therefore, more likely to sustain lethal chest and limb/skeletal injuries than head injuries compared to those who are younger, presumably due to greater physical fragility that occurs with age, with loss of protective muscle bulk and bone density.

Characteristics of crash-involved drink and drug car drivers and motorcyclists.

OBJECTIVE: Drug driving is an issue of growing concern among Australian jurisdictions, including South Australia. In order to have an appropriate response to drug driving in regard to policy and enforcement, it is important to have sound knowledge about the patterns of drug use among motorists and the associated risks of this behavior. METHOD: To this end, this study examined the characteristics of 1,277 hospitalized road users in South Australia in the years 2014 to 2017, with reference to whether or not they tested positive for alcohol or other drugs (the three drugs tested for according to the South Australian Road Traffic Act (1961): THC, methamphetamine, MDMA). This examination used a database combining hospital data, police-reported crash data, licensing information, and the result of alcohol and drug tests conducted by Forensic Science SA. RESULTS: It was found that more motorists were positive for one or more of the three illicit drugs than for alcohol, reversing long established trends. Comparisons were made between alcohol and drug free motorists, alcohol positive motorists, drug positive motorists, and motorists positive for both drugs and alcohol, with drivers of cars and motorcyclists analyzed separately where possible. Findings include: that those combining drugs and alcohol only comprise a small proportion of hospitalized motorists; that drug drivers tend to be younger than other hospitalized motorists; that drivers are more likely to test positive to alcohol or methamphetamine, while motorcyclists are more likely to test positive to THC; motorists testing positive to drugs and/or alcohol tend to exhibit a range of other risky behaviors; and motorists testing positive to drugs and/or alcohol tend to sustain more severe injuries in the event of a crash. CONCLUSIONS: Preventing drink and drug driving is important not only for reducing crash numbers but also injury severity in the event of a crash. Substance use differs by road user type and age, which has potential implications for enforcement practices.

Fatal blunt chest trauma: an evaluation of rib fracture patterns and age.

The following study was undertaken to determine if any specific occupant characteristics, crash factors, or associated injuries identified at autopsy could predict the occurrence or number of fractured ribs in adults. Data were accrued from the Traffic Accident Reporting System (TARS) and coronial autopsy reports from Forensic Science SA, Adelaide, South Australia, from January 2000 to December 2020. A total of 1475 motor vehicle fatalities were recorded in TARS between January 2000 and December 2020, and 1082 coronial autopsy reports were identified that corresponded to TARS fatal crash data. After applying exclusion criteria involving missing data, 874 cases were included in the analysis. Of the 874 cases, 685 cases had one or more rib fractures. The leading cause of death for those with rib fractures was multiple trauma (54%), followed by head injury (17%) and chest injuries (10%). The strongest predictor of one or more rib fractures was increasing age (p < 0.001). Other factors found in the regression to be predictive of the number of rib fractures were the presence of a variety of other injuries including thoracic spinal fracture, lower right extremity fracture, splenic injury, liver injury, pelvic fracture, aortic injury, lung laceration, and hemothorax. Age is most likely associated with increasing rib fractures due to reduced tolerance to chest deflection with greater injuries occurring at lower magnitudes of impact. The association of other injuries with rib fractures may be a marker of higher impact severity crashes.

Causes of fatalities in motor vehicle occupants: an overview.

Injuries from motor vehicle collisions are frequently encountered in routine forensic practice. While the most common lethal events involve blunt force trauma with injuries to the head and neck, chest, abdomen, pelvis and limbs, review of the literature and case files shows that a wide variety of other fatal situations can occur that may involve sharp force and penetrating trauma, incineration, drowning, asphyxia, organic diseases and combinations of these. The following overview details potential factors that may contribute to death following vehicle crashes.

Cardiac disease and driver fatality.

To determine the role of cardiac disease in driver fatalities, a retrospective review of autopsy files at Forensic Science SA in Adelaide, Australia, was undertaken over a 13-year-period January 2005-December 2017 for individuals aged ≥ 40 years who had died while driving a motor vehicle. The incidence of significant coronary artery atherosclerosis (CAA) and cardiomegaly was evaluated with comparisons between drivers and a control group of passengers. Autopsy examinations were performed on 303 drivers and 72 passengers who died of trauma and on 63 drivers who died of a cardiac event while driving. The average age for drivers dying of trauma was 58.5 years (range 40-93 years) with 48 (15.8%) having CAA and 31 (10.2%) having cardiomegaly. This was not statistically different to passengers (aged 63.3 years; range 40-93 years; 20.8% having CAA; 11 (15.2%) cardiomegaly; (p > 0.2). Drivers with significant cardiac disease did not, therefore, have increased rates of death in crashes, although a distinct subgroup of drivers consisted of those who had died from cardiac events and not trauma, while driving. The latter may be increasing in number given the aging population.

Profiling fatal and serious injury crashes in South Australia according to the Swedish transport administration model.

OBJECTIVES: This article describes a study examining fatal road crashes in South Australia (SA) according to the safety model developed by the Swedish Road Administration (STA). The STA model is based on the biomechanical limits that human beings can tolerate and specifies a number of elements that must be present for "compliance" with the model: driving at or below the speed limit, driver not intoxicated by alcohol or drugs, vehicle occupants wearing a seatbelt, car with a EuroNCAP rating of 5 stars, car equipped with electronic stability control, and a road with an EuroRAP rating of 4 stars. METHOD: The study used a sample of 105 fatal crashes in SA in 2010 and 2011 and a comparison sample of 136 serious injury crashes from 2014 to 2017. RESULTS: It was found that there were high levels of noncompliance with all elements of the STA model, with multiple forms of noncompliance in a clear majority of fatal cases. CONCLUSIONS: Considerable gains in safety could occur with greater penetration into the SA fleet of 5-star cars fitted with ESC and other vehicle safety technology, especially as the majority of both sets of crashes were of a type involving loss of vehicular control. It is also important to note that risky road user behavior was less common in the serious injury crashes and so a road safety strategy focusing on changing road user behavior will be ineffective for addressing the major factors contributing to non-fatal road trauma.

Issues that arise in the assessment of pedestrian deaths.

Road traffic crashes are responsible for the deaths of 1.35 million people annually around the globe, and pedestrian fatalities account for 23% of these cases. Issues that arise in assessing these deaths involve evaluation of the type of impact, the type and speed of the vehicle, the behavior of the pedestrian and the extent of the injuries. The types of injuries encountered at autopsy vary with age and body habitus. The forensic pathologist's role is to document injuries and to determine if and how they may have been caused by a particular vehicle(s). Patterned injuries may have been caused by impact with components of the vehicle chassis or from being run over by tires. Determining the manner of death may sometimes be problematic and suicides and homicides may be confused with accidents. The following commentary explores and discusses issues that arise in the assessment of these cases.

Methamphetamine and alcohol detection in vehicle-driver fatalities in South Australia: A 10-year survey (2008-2018).

Motor vehicle driver fatalities (≥18 years) from the files at Forensic Science South Australia were reviewed from January 2008 to December 2018 for cases in which either positive blood sample for methamphetamine (MA) or an illegal blood alcohol concentration (BAC) >0.05g/100 ml were found. Three hundred driver deaths were found with MA detected in 28 cases (age range 21-62 years; ave. 37.8 years; M:F 23:5). Hundred and fifteen cases with a BAC > 0.05 g/100 ml were identified (age range 18-67 years; ave 35.7 years; M:F 95:20). No change was found in numbers of MA cases, although alcohol cases showed a significant decline (p < 0.001). Drunk driving-related fatal crashes tended to occur in the evening (5 p.m. to 11 p.m.), while MA-related fatal crashes had a longer peak extending from late evening until late morning (11 p.m. to 8 a.m.). This study has demonstrated that while roadside breath testing, legislative changes, and increased monitoring have resulted in reduced levels of drunk driving, similar safety countermeasures have had negligible effects on MA use in drivers. Continued monitoring of MA use by drivers will, therefore, be necessary to assess the possible effects, or not, of new countermeasures.

Travel speed and the risk of serious injury in vehicle crashes.

While there is a large quantity of prior research on speed and road safety, no previous studies have quantified the absolute risk of serious injury in a crash relative to travel speed. This study aimed to produce risk curves that relate travel speed to the risk of serious injury in light vehicle impacts in order to contribute to the process of selecting acceptable travel speeds. Serious injury was defined in this study as any injury having a maximum abbreviated injury scale (MAIS) of three or greater, or a fatal injury (MAIS3+F). In the context of a crash, travel speed is defined as the vehicle's speed before the driver reacts to the crash situation. Travel speed was determined by selecting the highest pre-impact speed recorded by an Event Data Recorder (EDR) in the seconds before the crash. A total of 1,618 light vehicle impacts were analysed using logistic regression. Individual risk curves were produced for front, head on, side, rear and single vehicle impacts. The analysis found significant positive relationships between the risk of serious injury and travel speed for all of these impact types. The travel speeds at which the risk of serious injury reached one per cent were 63 km/h across all impacts, 17 km/h for head on impacts, 48 km/h for single vehicle impacts, 58 km/h for side impacts, 81 km/h for front impacts and 96 km/h for rear impacts. These results have implications for the setting of speed limits and other measures that influence the speed at which vehicles travel.

Upper and lower limb amputations in vehicle-related fatalities.

Traumatic limb amputation is rare in occupants following a motor vehicle collision (MVC). A retrospective analysis of autopsy reports at Forensic Science South Australia (FSSA) over a 19 year period from January 2000 to December 2018 was performed to determine the incidence of limb amputation in lethal collisions and to identify predisposing factors. Only 18 cases (1.54%) of occupant fatalities had a traumatic limb amputation with an age range of 18-78 years (mean 44.2 years), male to female ratio 13:5, and an average body mass index (BMI) of 28.5 (overweight). There were nine cases of upper limb amputation and nine cases of lower limb amputation (one case had both upper and lower limb amputations). Head on impacts without subsequent rollover were the most common collision type in both upper and lower amputation. The likely cause of limb amputation in vehicle crashes is, therefore, speed on impact rather than rollovers as has been previously suggested.

Impact speed and the risk of serious injury in vehicle crashes.

The current guiding philosophies in road safety have stated aims of zero deaths and serious injuries. Speed has previously been highlighted as a key factor in the outcome of a crash but the literature to date has yet to provide a robust relationship between impact speed and the risk of serious injury for crashes other than pedestrian crashes. This study aimed to determine the relationship between impact speed and the risk of serious injury in light vehicle crashes. Crash data from the US based National Automotive Sampling System - Crashworthiness Data System collected from 2011 to 2015 were used in the analysis when there was a known impact speed from an event data recorder (EDR) and a known injury outcome. The analysis was conducted at the vehicle level. Data from a total of 1274 vehicles were used in logistic regressions, with the presence or absence of a serious injury as the binary dependent variable, and impact speed as the continuous independent variable. Individual risk curves were produced for front, side, rear and head on impacts. Impact speed was found to have a highly significant positive relationship to risk of serious injury for all impact types examined. The risk of serious injury reaches 1% at 28 km/h for head on impacts, 51 km/h for side impacts, 64 km/h for front impacts, and 67 km/h for rear impacts. The results emphasise the importance of measures that reduce impact speeds, be they road designs, vehicle technologies or enforced speed limit reductions, and highlight the need to prevent head on impacts.

Childhood cycling fatalities in South Australia before and after the introduction of helmet legislation.

In the years following the introduction of legislation in Australian states mandating the wearing of helmets, there was a decline in the number of deaths. Debate has occurred, however, as to why this occurred. The Traffic Accident Reporting System database, which records data for all police-reported crashes in South Australia, was searched for all cases of deaths occurring in the state in bicycle riders aged ≤14 years from January 1982 to December 2001. The numbers of deaths were then compared over the 10-year periods before (1982-1991) and after (1992-2001) the introduction of helmet legislation, and also on a yearly basis from 1982 to 2001. Comparing the numbers of deaths in the two periods before and after helmet legislation in 1991 showed a marked decrease in cases from 36 to 12. However, in examining the numbers of deaths per year in greater detail, it appears that these were already steadily reducing from nine cases per year in 1982 (2.9/100,000) to two cases in 1991 (0.67/100,000) to a virtual plateau after 1991 (ranging from 0 to 2 cases annually). It seems that the introduction of compulsory bicycle helmet wearing in South Australia came at a time when the numbers of child cyclist deaths had been steadily declining over the preceding decade. While helmet wearing clearly protects children who are still riding bicycles, the reasons for the reduction in numbers of deaths appears more complex than legislative change and likely involves a subtle interaction with other behavioural and societal factors and preferences.

Illicit drugs are now more common than alcohol among South Australian crash-involved drivers and riders.

Objectives: For a jurisdiction to apply appropriate countermeasures for impaired driving, it is necessary to track drug and alcohol involvement in road crashes. In South Australia, it is mandated that all injured road users aged over 10 who attend a hospital for treatment must have a blood sample taken, which is tested for alcohol and drugs. The drug testing covers the three drugs included in South Australia's roadside drug testing program: delta-9-tetrahydrocannabinol (THC or cannabis), methamphetamine ('ice') and 3,4-methylenedioxymethamphetamine (MDMA or 'ecstasy').Methods: The present study involved analysis of the results of drug tests from 2014 to 2017 for road users over the age of 16 at the major trauma hospital in Adelaide, the capital city of South Australia. Comparisons were made to the results of blood tests from an earlier study using data from 2008 to 2010.Results: It was found in the most recent dataset that just over 11 per cent of drivers and just under 5 per cent of motorcyclists had a blood alcohol concentration (BAC) above the legal limit of 0.05 g/100 ml. In regard to the three proscribed drugs, the rates for both drivers and motorcyclists were over 15 per cent. Among drivers, methamphetamine was most common (9.7%), followed by THC (6.3%). Among motorcyclists, THC was most common (9.4%), followed by methamphetamine (6.2%). Inspection of data from 2008 to 2010 reveals that rates of having an illegal BAC when involved in a crash have declined over the past decade (from 20.2% down to 9.3%), while rates of drug use among crash involved drivers and riders have increased (from 10.5% to 15.2%).Conclusions: Although the apparent decline in alcohol involvement in road crashes in recent years in South Australia is to be welcomed, the increasing proportion of road crashes involving drug impaired drivers, particularly those affected by methamphetamine, is cause for concern. A National Drug Driving Working Group has been set up by Austroads to examine improvements in drug driving enforcement practices. The recommendations arising from their work need to be considered for implementation to prevent rising drug driving crashes from replacing the reduction in road crashes attributable to drink driving.

Near-miss crashes and other predictors of motorcycle crashes: Findings from a population-based survey.

OBJECTIVE: Crash and injury surveillance studies have identified a range of rider-related factors, including age, sex, licensure, training and experience, as being associated with motorcycle crash risk. The aim of this study was to establish whether these previously identified factors were associated with crash involvement in an Australian-based population. METHODS: Data obtained from motorcyclists recruited from road authority licensing offices in a population-based survey design were analyzed. In addition to descriptive analysis, survey logistic regression was used to examine predictors of self-reported motorcycle crashes. A statewide population prevalence study of motorcyclists in New South Wales, Australia, was conducted using a multistage stratified random sampling plan. Participants (n = 503) represented 47% of eligible riders invited to participate. The distribution of responses was weighted to represent the population based on motorcycle registrations as a proxy for active motorcyclists, adjusted for age, sex, and variations in sample size and population density between survey sites. RESULTS: This analysis investigated factors associated with having crashed in the past 12 months. The key predictors of increased crash risk included frequent near-crash experiences (6-10) in the past year (adjusted odds ratio [ORadj] = 5.3; 95% confidence interval [CI], 1.3-21.8), having 4 or more riding demerit points (ORadj = 4.1; 95% CI, 1.1-14.7), and motorcycle type and riding purpose. Sports (ORadj = 2.8; 95% CI, 1.1-7.3) and commuter motorcycles (ORadj = 4.0; 95% CI, 1.1-15.3) were associated with higher odds of crashes compared to cruiser/touring motorcycles. Those whose purpose for riding frequently involved commuting, high-speed roads, or motorcycle sports had higher odds of being involved in a crash compared to riders who rarely took part in such activities. Rider age, license type, and time holding a motorcycle license were not predictive of crash involvement when other factors were taken into account. CONCLUSIONS: These findings provide important population-level information and insights about risk exposure for motorcyclists. Taking a more tailored approach to data collection meant that factors associated with crash involvement were identified that are not commonly observed in studies relying on administrative data. In particular, the study highlights the importance of near-crash experiences as warnings to riders and the need to use such experiences as learning opportunities to improve their riding style and safety.