Annual performance indicators of enforced driver behaviours, 2002

The Centre for Automotive Safety Research at the University of Adelaide was commissioned by Transport SA to produce a report quantifying the effects of selected enforced driver behaviours: drink driving, speeding and restraint use, in South Australia for the calendar year 2002. The level of random breath testing (RBT) has increased substantially such that the annual average rate of testing was 2 tests for every 3 licensed drivers in 2002. An inverse relationship between detection rates and publicity expenditure suggests current publicity campaigns are supporting enforcement operations. Overall, speeding detection rates in 2002 decreased, especially speed camera detection rates. However, speeding detection rates were heavily influenced by police enforcement strategies and practices. Rural speed surveys indicated that the mean free speed decreased from 2000 to 2002 on 100km/h roads but showed no meaningful change on 60km/h and 110km/h roads each year. Determining the effectiveness of restraint use enforcement was very difficult because no specific restraint enforcement campaigns were undertaken. In the absence of available restraint enforcement details, the number of restraint related offences committed annually was used to provide a rough estimate of enforcement activities. Reasonably consistent observational surveys were useful in providing an indication of restraint wearing rates over time in a number of regions. The surveys indicated that both metropolitan and rural wearing rates increased in 2002 to a level of 96 per cent, just above the national target of 95 per cent.L.N. Wundersitz and A.J. McLea

Edge delineations

In 2001, the Motor Accident Commission (MAC) sponsored a trial of a comparatively inexpensive form of audio tactile raised pavement marker as a fatigue driving countermeasure on the Dukes Highway east of Keith, South Australia. MAC has asked the Centre for Automotive Safety Research (CASR) to comment on the relevance of this treatment including its compliance with road design rules, its cost effectiveness when compared to other treatments and any safety issue with their useJ.E. Woolley and A.J. McLea

Older drivers: Crash involvement rates and causes

This report presents an analysis of the claims that older drivers are over-represented in road crashes and an examination of the nature of the ‘older driver problem’ in so far as it exists. Four different types of crash rates (crash numbers, crashes per head of population, crashes per licensed driver, crashes per distance driven) are considered, with emphasis placed on problems in interpretation of the various crash rates and what information can be derived from each of them. It is concluded that the crash rates of most importance are total crash numbers and crashes per licensed driver, neither of which were found to feature an over-representation of older drivers. Also addressed in the report is the question of whether the increase in crash rates per distance driven might be a phenomenon associated with older drivers as a whole, or one associated with specific subgroups of older drivers whilst the remainder maintain the relatively low crash rates of middle-aged drivers. Although there are arguments to support the claim that there are high risk subgroups of older drivers, it is nevertheless concluded that high risk older drivers cannot be identified in mass crash data. A third section of the report contains an analysis of a sample of crashes involving older drivers that were investigated as part of an in-depth study into rural road crashes. The factors other than the driver which contributed to the occurrence of the crashes are discussed, illustrating the importance of appropriate road infrastructure for reducing older driver crashes.M.R.J. Baldock and A.J. McLea

Vehicle design for pedestrian protection

This report is a review of the regulation of vehicle design as it relates to the protection of a pedestrian in the event of a collision. It commences with a brief description of the background to the current approach to regulation in this area and then gives an overview of the requirements of the European and Japanese regulations. Moves by the UN/ECE through the Global Technical Regulations to develop an internationally acceptable standard are described in the context of the existing regulations and the on-going work of the International Harmonised Research Activities Pedestrian Safety Working Group. The report concludes with a description of the proposed European Directive for the regulation of the design of vehicle frontal protection systems (bull bars) to reduce the risk of injury to a pedestrian in a collision, and a comparison of these proposed requirements with the Australian Standard for Vehicle Frontal Protection Systems.AJ McLea

Fitness Effects of Somatic Mutations on Mimulus aurantiacus Progeny

Unlike animals, plants possess the unique ability to pass on mutations to progeny that arise both through meiotic (germline) and mitotic (somatic) division. In spite of these two sources of genetic variation, mutation rates per generation appear to be similar between plants and animals. One explanation for this discrepancy is cell lineage selection (CLS), which claims that cell lineages with deleterious somatic mutations are sieved out of the population of cells in a plant’s shoot apical meristem through natural selection. On the other hand, beneficial mutations may become fixed within the population. To investigate the plausibility of CLS, I performed multiple experiments to determine the fitness effects of somatic mutations by comparing the progeny of Mimulus aurantiacus plants generated via self-pollination made within the same flower (autogamy) to progeny from self-pollinations made between stems on the same plant (geitonogamy). Importantly, autogamy leads to homozygosity of a proportion of somatic mutations, but progeny from geitonogamy remain heterozygous for mutations unique to each stem. Significant differences in fitness were observed among some autogamous and geitonogamous progeny. Surprisingly, autogamous progeny from several genets displayed significantly increased fitness, which challenges the assumption that differences in fitness between autogamous and geitonogamous progeny are caused solely by deleterious mutations. These results support the hypothesis that somatic mutation accumulation during vegetative growth can result in non-negligible—and possibly beneficial—changes in fitness among progeny due to CLS

Adelaide in-depth accident study 1975-1979. Part 8: Summary and recommendations

This report contains a summary of the conclusions and recommendations from earlier reports on the causes and consequences of a representative sample of road traffic accidents to which an ambulance was called in metropolitan Adelaide. Brief comments on the study as a whole are included. The abstracts, tables of contents, introductions and conclusions and recommendations from Parts 1 to 7 and 9 and 10 are presented in appendices.A.J. Mclea

Evaluation of the South Australian default 50 km/h speed limit

On 1 March 2003 the default urban speed limit in South Australia was reduced from 60 km/h to 50 km/h. On-road speeds just before the default limit was introduced were compared with speeds a year later. The numbers of casualty crashes and casualties in the year before the default limit was introduced were compared with the corresponding numbers in the first year that the default limit was in effect. On roads where the speed limit was reduced from 60 km/h to 50 km/h, average vehicle speeds decreased by 2.3 km/h and casualties by 24 per cent. On roads where the speed limit remained at 60 km/h, average vehicle speeds decreased by 0.9 km/h and casualties by 7 per cent.C.N. Kloeden, J.E. Woolley and A.J. McLea

Front side window tinting visual light transmittance requirements

The Australasian Branch of the International Window Film Association has lobbied for approval for tinting of front side windows of cars down to a level such that 35% of incident visible light is transmitted through to the driver. South Australia currently has a minimum level of visible light transmittance of 70% for front side windows. This Report explores the safety implications of the proposed greater levels of tinting on front side windows and concludes that road safety would be adversely affected by allowing such a move.M.R.J. Baldock, A.J. McLean and C.N.Kloede

Reduction of speed limit from 110 km/h to 100 km/h on certain roads in South Australia: a preliminary evaluation

In July 2003, the speed limit on approximately 1,100 km of rural arterial roads in South Australia was reduced from 110 km/h to 100 km/h. The crash experience on these roads in the two years before and the two years following the change has been compared with that on other roads where the 100 km/h limit was not changed. It appears that the speed limit reduction has had the effect of reducing casualty crashes by 20 per cent. However, the number of crashes on these roads is small and the time since the change is so short that this estimate is uncertain. It is reasonable to think that in the longer term the change might be anywhere between an increase of 4 per cent and a decrease of 44 per cent. There was a decrease in crashes and casualties on the 100 km/h roads where the speed limit did not change and that has been allowed for in the calculations. At six sites, speed measurements before and after the speed limit reduction were available: an average speed reduction of 2 km/h was foundA.D. Long, C.N. Kloeden, T.P. Hutchinson and A.J. McLea

A randomised controlled trial comparing graded exercise treatment and usual physiotherapy for patients with non-specific neck pain (the GET UP neck pain trial).

Evidence supports exercise-based interventions for the management of neck pain, however there is little evidence of its superiority over usual physiotherapy. This study investigated the effectiveness of a group neck and upper limb exercise programme (GET) compared with usual physiotherapy (UP) for patients with non-specific neck pain. A total of 151 adult patients were randomised to either GET or UP. The primary measure was the Northwick Park Neck pain Questionnaire (NPQ) score at six weeks, six months and 12 months. Mixed modelling identified no difference in neck pain and function between patients receiving GET and those receiving UP at any follow-up time point. Both interventions resulted in modest significant and clinically important improvements on the NPQ score with a change score of around 9% between baseline and 12 months. Both GET and UP are appropriate clinical interventions for patients with non-specific neck pain, however preferences for treatment and targeted strategies to address barriers to adherence may need to be considered in order to maximise the effectiveness of these approaches