Angela Watson

Estimating under-reporting of road crash injuries to police using multiple linked data collections.

The reliance on police data for the counting of road crash injuries can be problematic, as it is well known that not all road crash injuries are reported to police which under-estimates the overall burden of road crash injuries. The aim of this study was to use multiple linked data sources to estimate the extent of under-reporting of road crash injuries to police in the Australian state of Queensland. Data from the Queensland Road Crash Database (QRCD), the Queensland Hospital Admitted Patients Data Collection (QHAPDC), Emergency Department Information System (EDIS), and the Queensland Injury Surveillance Unit (QISU) for the year 2009 were linked. The completeness of road crash cases reported to police was examined via discordance rates between the police data (QRCD) and the hospital data collections. In addition, the potential bias of this discordance (under-reporting) was assessed based on gender, age, road user group, and regional location. Results showed that the level of under-reporting varied depending on the data set with which the police data was compared. When all hospital data collections are examined together the estimated population of road crash injuries was approximately 28,000, with around two-thirds not linking to any record in the police data. The results also showed that the under-reporting was more likely for motorcyclists, cyclists, males, young people, and injuries occurring in Remote and Inner Regional areas. These results have important implications for road safety research and policy in terms of: prioritising funding and resources; targeting road safety interventions into areas of higher risk; and estimating the burden of road crash injuries.

Predicting crashes using traffic offences. A meta-analysis that examines potential bias between self-report and archival data

Background Traffic offences have been considered an important predictor of crash involvement, and have often been used as a proxy safety variable for crashes. However the association between crashes and offences has never been meta-analysed and the population effect size never established. Research is yet to determine the extent to which this relationship may be spuriously inflated through systematic measurement error, with obvious implications for researchers endeavouring to accurately identify salient factors predictive of crashes. Methodology and Principal Findings Studies yielding a correlation between crashes and traffic offences were collated and a meta-analysis of 144 effects drawn from 99 road safety studies conducted. Potential impact of factors such as age, time period, crash and offence rates, crash severity and data type, sourced from either self-report surveys or archival records, were considered and discussed. After weighting for sample size, an average correlation of r = .18 was observed over the mean time period of 3.2 years. Evidence emerged suggesting the strength of this correlation is decreasing over time. Stronger correlations between crashes and offences were generally found in studies involving younger drivers. Consistent with common method variance effects, a within country analysis found stronger effect sizes in self-reported data even controlling for crash mean. Significance The effectiveness of traffic offences as a proxy for crashes may be limited. Inclusion of elements such as independently validated crash and offence histories or accurate measures of exposure to the road would facilitate a better understanding of the factors that influence crash involvement.

The effects of licence disqualification on drink-drivers:Is it the same for everyone?

Drink-driving remains a major road safety concern that creates a significant social burden. Licence disqualification continues to play a key role in drink driving deterrence and sanctions together with police enforcement to address the problem in most motorised countries. However, on-going questions remain regarding the differing effect of licence disqualification periods between first time and repeat offenders, and between other sub-groups of offenders. As a result, this study aimed to determine whether: (a) differences exist in re-offence rates of convicted drink-drivers between: the period between committing the drink-driving offence and licence disqualification (pre-licence disqualification), during the period of licence disqualification, and after being re-licensed (post-licence restoration); and (b) differential effects of offence rates are evident based on Blood Alcohol Content (BAC), gender, age, repeat offender status and crash involvement at the time of offence. The sample consisted of 29,204 drink-driving offenders detected in Victoria, Australia between 1 January 1996 and 30 September 2002. The analysis indicated that licence disqualifications were effective as drink-driving offenders had a significantly lower rate of offending (both drink-driving and other traffic offences) during licence disqualifications compared to pre-licence disqualification and post-licence restoration periods. The influence of licence disqualification appeared to extend beyond the disqualification period, as offence rates were lower during post-licence restoration than during pre-licence disqualification. Interestingly, the highest rate of offending (both for drink-driving and other traffic offences) was during the pre-licence disqualification period, which suggests offenders are particularly vulnerable to drink and drive while waiting to be sanctioned. A consistent pattern of results was evident across genders and age groups. Additionally, those who were involved in a crash at the same time as their index offence had lower offence rates (compared to those who were not involved in a crash) for all periods, although for general traffic offences, the offence rate was highest in the post-licence restoration period for those who had a crash at index offence. This indicates that being involved in a crash may deter these offenders, at least in the short-term. The implications of the results for managing both first time and repeat offenders are discussed.

Falls from ladders in Australia: comparing occupational and non-occupational injuries across age groups.

Objective: To examine national ladder‐related fall injury patterns and trends, and compare the changes over time in occupational and non‐occupational falls across age groups.

863 Understanding the profile of injuries for vulnerable road users: a data linkage study

Background Unless substantial gains are made in the prevention of road crashes, they will become the third ranked global burden of disease and injury by 2020. A growing proportion of this burden relates to vulnerable road users (e.g., motorcyclists, cyclists, and pedestrians). In order to reduce this burden, there is a need to fully understand the nature and contributing circumstances of crashes and the resulting injuries. While police-reported crash data contain detailed information about crash circumstances, they lack accurate information about the severity and nature of injuries which are included in hospital data. By bringing these data collections together using data linkage, the relationship between the characteristics of vulnerable road user crashes and their resulting injuries were explored. Methods Data from the Queensland Road Crash Database (QRCD) and the Queensland Hospital Admitted Patients Data Collection (QHAPDC) for the year 2010 were linked. There were 1,382 police-reported motorcyclist injuries that linked to a hospital record (42% of all police-reported motorcyclist injuries), 429 cyclists (25%), and 644 (39%) pedestrians. The relationships between crash characteristics such as counterpart involvement, alcohol, fatigue, speed, and helmet use and injury severity (e.g., ICD-derived Injury Severity Score ICISS, length of stay), nature, and body region were examined. Results The involvement of motor vehicles was related to more severe injury outcomes for vulnerable road users (between 1.5 and 2.8 times the odds of being serious), as were high speeds (between 1.2 and 1.6 times), alcohol (2.1 times for motorcycles), and helmet non-use (between 1.9 and 2 times). The circumstances of crashes, such as counterpart type and crash location, influenced injury nature and body region. Conclusions By bringing together circumstance data from police and injury outcome data from hospitals, a greater understanding of the link between crash circumstances and injury outcomes was achieved. Studies using linked data can better inform intervention and treatment for a more holistic approach to the reduction of road trauma for vulnerable road users.

860 Safe following distance? –driver perceptions to help reduce rear end road crashes in Australia

Background To reduce road trauma we must better understand the factors contributing to crashes. In Queensland, Australia, rear end crashes are the 3rd leading crash type, with mild to serious injuries a likely outcome and whiplash a common injury occurrence. Road design, traffic congestion, and weather/road conditions have been implicated in rear end crashes. Human factors also play a key role, with the act of ‘following too closely’ being a major issue. Queensland legislation requires motorists to maintain a safe following distance between their vehicle and the one in front, although no specific information about this distance is prescribed by law for cars. Methods To better understand perceptions of safe following distance, 495 licensed Queensland drivers (42% male; mean age 46.2 yrs; range 16–81 yrs) completed an online questionnaire. Results Overall, there was wide variation in descriptions of safe following distance including time between vehicles (2 seconds = 21%; 3 seconds = 11%), distance between vehicles (metres = 11%; car lengths = 32%); and combinations of time and distance (1%). No one reported having received an infringement for not keeping a safe following distance, although 29% reported being involved in a crash where their vehicle hit the one in front. The majority (86%) reported that it was somewhat-extremely unlikely they would be caught by police if following too closely, indicating a perceived lack of enforcement for this offence. Reasons for this included perceptions of difficulty for police to enforce this offence (5%), not having heard of anyone being caught for this offence (17%), and other police priorities (30%). Conclusions This study is part of a larger research project that aims to improve knowledge about driving conditions, patterns and locations, and driver behaviours that lead to driving at unsafe headways (i.e. following too closely). Recommendations for use of these findings to inform driver education and awareness campaigns are discussed.