Countermeasures to the problem of accidents to intoxicated pedestrians.

A substantial part of the pedestrian accident problem arises from intoxicated pedestrians. Possible countermeasures are reviewed, organised into: (a) prevention of high levels of intoxication in pedestrians, (b) minimising pedestrian activity in the intoxicated, and (c) minimising risk of injury among intoxicated pedestrians. It is concluded that improved safety of intoxicated pedestrians is most likely to come about by making the environment safer for all pedestrians, drunk or sober. The measure that would be expected to have the greatest effect quickest is a reduced speed limit, especially in locations where traffic is busy and there are many pedestrians.

Age, sex, and blood alcohol concentration of killed and injured drivers, riders, and passengers.

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.

Brain injury patterns in fatally injured pedestrians.

To study the relationship between the severity of impact to the head and the severity and distribution of injury to the brain in fatally injured pedestrians, events in vehicle-pedestrian collisions were reconstructed to determine the peak linear and angular acceleration sustained by the pedestrians' heads. The nature and distribution of injuries to the brain were determined by neuropathologic examination of coronal sections of the brain. Study of 13 cases with occipital impacts and 18 with lateral impacts showed that the brain appeared to be more susceptible to injury from lateral impacts. The frontal and temporal regions appeared to be more susceptible to injury at low accelerations in occipital impacts, providing an explanation for "coup" and "contrecoup" injuries. For occipital impacts, a positive relationship was found between linear acceleration and the extent of injury to the brain, suggesting that there was a threshold for observable and concussive brain injury at about 1500 m/s2 peak linear acceleration. These findings are important for the development of measures for preventing brain injuries.

Estimated and measured blood alcohol levels in the night-time driving population.

The aim of this study was to compare drivers' subjective estimates of their blood alcohol concentration (BAC) with their measured BAC. As part of a night-time survey of drinking and driving in the Adelaide metropolitan area, 13 951 drivers were approached at intersections between 10 p.m. and 3 a.m. and asked to provide a breath alcohol sample. In addition, drivers were given a reply-paid mail questionnaire which sought their own estimate of their BAC. The 5765 replies were compared with the measured BACs. It was found that drivers with low measured BACs tended to over-estimate their BAC while drivers with high BACs tended to under-estimate; the error in the estimates increased as measured BAC increased. These errors were similar for males and females and did not vary with age group. These results emphasize the need for the wider adoption of reliable means by which people can assess their own BAC more accurately.

Extradural haematoma: trends in outcome over 35 years.

We have reviewed 35 years experience of extradural haemorrhage (EDH) in a large neurosurgical unit, based in two university hospitals, one dealing exclusively with children and the other a general hospital. A steady reduction in the mortality rate from 29 to 8.5% occurred during that period. A trend towards earlier diagnosis is noted and an increasing proportion of rural patients has been evident throughout the study period. During the time-period studied there were many significant developments: the establishment of a modern neurosurgical unit, the evolution of an intensive care unit, the availability of CT head scanning and the formal organization of rapid retrieval to service country areas. However, no single feature could be identified as the major contributor to falling mortality results. Clinical awareness and early diagnosis are the keys to successful management of EDH.

Drink-driving in the general night-time driving population, Adelaide 1989.

A roadside breath alcohol survey was conducted by the NHMRC Road Accident Research Unit in 1989 to monitor the efficacy of random breath testing (RBT) by the police. A reduction of 40 per cent in the proportion of drivers above the legal blood alcohol limit of 0.08 g/100 ml was found to coincide with a marked increase in the level of publicity of police RBT operations. Other factors may also have contributed to these large reductions in illegal drink-driving but this result was similar to that observed in 1987 when a major increase in publicity was accompanied by an increase in the level of enforcement of RBT. Although the full effect of these reductions has diminished with time, there appears to have been a decrease in illegal drink-driving in Adelaide from 1983 to 1987 and again to 1989.