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.

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).

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.

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.

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.

Lethal mechanisms in cases of inverted suspension from the lap component of seat belts.

A retrospective review of autopsy files at Forensic Science South Australia in Adelaide, Australia, was undertaken over a five-year period from January 2014 to December 2018 for all motor vehicle crashes with rollovers ending with the vehicle inverted and the occupants suspended by the lap component of their seat belts. There were five cases, all male drivers (aged 18-67 years; Mage = 32 years). Acute neck flexion or head wedging was noted in four cases, with facial petechiae in four and facial congestion in one. Deaths were due to positional asphyxia in four cases, with the combined effects of positional asphyxia and head trauma accounting for the remaining case. Although all drivers had evidence of head impact which may have caused incapacitation, in only one case was this considered severe enough to have contributed to death. A blood alcohol level above the legal limit for driving was detected in two cases, but no other drugs were detected. This series demonstrates another subset of cases of seat belt-associated deaths where suspension upside down by the lap component of a seat belt had occurred after vehicle rollovers. Predisposing factors include incapacitation of the victim and delay in rescue. The postulated lethal mechanism involved respiratory compromise from the weight of abdominal viscera on the diaphragm, as well as upper airway compromise due to kinking of the neck and wedging of the head.

Seat belt asphyxia as a lethal mechanism in motor vehicle crashes.

A 28-year-old driver was found dead in his car after impact with a truck. At the scene he was seated in the driver's seat partially hanging out of the vehicle with the sash component of the seatbelt tightly pressed into his neck. At autopsy there was evidence of neck compression with bilateral conjunctival petechial hemorrhages and fracture of the right superior horn of the thyroid cartilage. Limb fractures and internal injuries were not associated with significant hemorrhage. There was no evidence of brain trauma. Death was, therefore due to neck compression from the seatbelt demonstrating an additional rare lethal mechanism that may be encountered in vehicle crashes. External bruises and abrasions may not be present around the neck due to padding from clothing, however conjunctival petechiae and neck injuries are supportive of the diagnosis.

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.

Factors involved in the assessment of paediatric traffic injuries and deaths.

Motor-vehicle collisions are the leading cause of unintentional injury and death in children in many parts of the world, including Europe, North America and Australia. The number of fatal collisions has decreased considerably in countries where safety measures such as child restraints, seat belts and air bags have been introduced, providing protection for children within vehicles, although it is recognised that there have been concomitant improvements in emergency responses and techniques, and in hospital treatments. Helmets and changes in external vehicle designs have been implemented to protect paediatric pedestrians and cyclists. However, despite the development of safety guidelines and technologies, injuries still occur. This paper provides an overview of the role of motor-vehicle collisions in paediatric morbidity and mortality to analyse the nature and aetiology of common fatal and non-fatal injuries in children that may present for forensic assessment as passengers, pedestrians or cyclists.

"Defense" type wounds in suicide.

"Defense" type wounds are sustained when a victim is attempting to ward off an attacker, or a weapon. A 39-year-old woman is reported who was found deceased with incised wounds to the dorsa of both hands that resembled defense wounds. Examination of the flexor surfaces of both wrists, however, revealed horizontal incised wounds typical of self-infliction. Perfusion of the subclavian arteries produced leakage of water from peripheral veins within wounds on both hands and the right wrist. Death was due to exsanguination from incised wounds of the hands and right wrist; manner suicide. This case demonstrates the difficulties that may arise in differentiating self-inflicted from assaultive wounds. On occasion suicidal sharp force injuries may be multiple and in atypical locations. In these circumstances a high index of suspicion for homicide must be maintained.

Familial Vehicular Murder-Suicide.

A certain number of single-vehicle crashes into stationary roadside objects such as trees are thought to be occult suicides. However, is it possible that some cases of multiple deaths within a family in similar crashes are due to unrecognized familial murder-suicides? A 39-year-old woman and her 11-year-old daughter are reported who died of injuries following a vehicle impact with a tree. Unusual behavior of the mother leading up to the crash, and assessment at the scene, raised the possibility of this being a nonaccidental event. However, difficulties in retrospectively determining the intent of a driver in a vehicle crash, and the nonrecording of, or lack of separate coding for murder-suicides on registers, make determination of the incidence of these types of events extremely difficult. It may be that this is a subcategory of murder-suicide that is underdiagnosed and so is not being registered on central motor vehicle crash databases.