Adjusting vehicle secondary safety ratings to account for crash-avoidance technology fitment using real-world crash and injury data.

OBJECTIVES: Publicizing safety ratings of vehicles can motivate manufacturers to prioritize safety and help consumers choose safer vehicles, leading to safer fleets. The benefits of primary safety technologies that prevent crash occurrence are not currently incorporated in current ratings in a way that values their safety benefits consistently. We aimed to propose a method for assigning weights for each safety technology to account for established safety benefits using published effectiveness and prevalence from real-life data. METHODS: To illustrate this method, we present a worked example calculated using crash and injury data from Australia and New Zealand. The method proposed attenuates the weights for given safety technologies where two or more safety technologies fitted to the same vehicle are effective for the same types of crashes. RESULTS: In the worked example using Australasian data, large SUVs were estimated to have the largest safety increment from the fitment of all the technologies considered compared to vehicles without these primary safety technologies, with an almost 17% reduction in crash occurrence. Cars with all the technologies fitted had estimated average crash reduction of between 11% and 12%. CONCLUSIONS: Different market groups have different crash patterns, so the safety attributable to safety technology fitment differs at the market group level. This study presents an approach for providing a summary measure of crash avoidance according to the fitment of safety technologies. If this measure is combined with an estimate of secondary safety (whether derived from existing crash and injury data or from new car crash assessment programs), the combined estimate then represents the important elements of safety provided by the vehicle. The methods presented here form a rational basis for assigning safety ratings to represent the benefits of swiftly developing safety technologies.

Home modifications to prevent home fall injuries in houses with Maori occupants (MHIPI): a randomised controlled trial.

BACKGROUND: As with many Indigenous populations internationally, Maori in New Zealand suffer health inequity. We aimed to assess the rate of fall injuries at home with and without home modifications in houses with Maori occupants. METHODS: We did a single-blind randomised controlled trial in the Wellington and Taranaki regions of New Zealand and enrolled owner-occupied households with at least one Maori occupant. Only households who stated they intended to live at that address for the subsequent 3 years were eligible for participation. We randomly assigned (1:1) households to either the intervention group, who received home modifications (handrails for outside steps and internal stairs, grab rails for bathrooms, outside lighting, repairs to window catches, high-visibility and slip-resistant edging for outside steps, fixing of lifted edges of carpets and mats, non-slip bath mats, and slip-resistant surfacing for outside areas such as decks) immediately, or the control group, who received the modifications 3 years later. Data on home injuries were obtained from the Accident Compensation Corporation and coded by study team members, who were masked to study group allocation. The primary outcome was the rate of medically treated fall injuries at home per household per year, analysed according to intention to treat. This Maori Home Injury Prevention Intervention (MHIPI) trial is now completed, and is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12613000148774. FINDINGS: Between Sept 3, 2013, and Oct 1, 2014, 824 households were assessed for eligibility and 254 were enrolled, of which 126 (50%) were assigned to the intervention group and 128 (50%) were assigned to the control group. After adjustment for previous falls and geographical region, there was an estimated 31% reduction in the rate of fall injuries at home per year exposed to the intervention compared with households in the control group (adjusted relative rate 0·69 [95% CI 0·47-1·00]). INTERPRETATION: Low-cost home modifications and repairs can be an effective means to reduce injury disparities. The high prevalence of modifiable safety issues in Maori homes merits considerable policy and community effort. FUNDING: Health Research Council of New Zealand.

Evaluation of the effectiveness of vehicle roll stability control (RSC) for high center of gravity light passenger vehicles in Australasia.

OBJECTIVE: Rollover crashes, which occur when the vehicle's side or roof makes impact with the ground, present particularly serious injury risk. Higher rollover risk has been found for high riding vehicles - those with a relatively high center of gravity compared to the width of the wheel track. Electronic Stability Control (ESC), which automatically applies brakes to individual wheels and reduces engine power to help drivers regain control when traction is lost, has been shown to be effective in preventing a proportion of rollovers. A newer safety technology, Roll Stability Control (RSC), uses similar technology aimed specifically to reduce rollover risk. This study sought to estimate rollover crash rates associated with the fitment of RSC compared to non-fitment for high center of gravity (CG) light passenger vehicles using an induced exposure analysis. METHODS: Police-recorded Australasian crash data were studied for the years 2008-2017. A quasi-induced exposure analysis was restricted to vehicles already equipped with ESC as vehicles fitted with RSC always have ESC fitted. Rollover risk associated with RSC fitment was assessed, controlling for year of crash, speed limit at crash location, year of vehicle manufacture, vehicle market group, driver age, driver gender and jurisdiction identifier. RESULTS: The analysis found a statistically significant rollover risk ratio of 0.76 (95% CI 0.62-0.93), representing a 24% reduction in rollover risk, associated with RSC fitment for vehicles manufactured between 2008 and 2017. Analysis by particular market groups found significant risk ratio reductions for commercial utilities and large SUVs, but not for the other high CG market groups individually. CONCLUSIONS: These results suggest that RSC is a highly effective safety feature for high CG vehicles. Fleet data from Australia and New Zealand showed declining rates of RSC fitment over recent years for SUVs, meaning the potential road safety benefits of the technology are not being fully realized.

Cost-benefit analysis of fall injuries prevented by a programme of home modifications: a cluster randomised controlled trial.

BACKGROUND: Injuries due to falls in the home impose a huge social and economic cost on society. We have previously found important safety benefits of home modifications such as handrails for steps and stairs, grab rails for bathrooms, outside lighting, edging for outside steps and slip-resistant surfacing for outside areas such as decks. Here we assess the economic benefits of these modifications. METHODS: Using a single-blinded cluster randomised controlled trial, we analysed insurance payments for medically treated home fall injuries as recorded by the national injury insurer. The benefits in terms of the value of disability adjusted life years (DALYs) averted and social costs of injuries saved were extrapolated to a national level and compared with the costs of the intervention. RESULTS: An intention-to-treat analysis was carried out. Injury costs per time exposed to the modified homes compared with the unmodified homes showed a reduction in the costs of home fall injuries of 33% (95% CI 5% to 49%). The social benefits of injuries prevented were estimated to be at least six times the costs of the intervention. The benefit-cost ratio can be at least doubled for older people and increased by 60% for those with a prior history of fall injuries. CONCLUSIONS: This is the first randomised controlled trial to examine the benefits of home modification for reducing fall injury costs in the general population. The results show a convincing economic justification for undertaking relatively low-cost home repairs and installing safety features to prevent falls. TRIAL REGISTRATION NUMBER: ACTRN12609000779279.

Development of a method to rate the primary safety of vehicles using linked New Zealand crash and vehicle licensing data.

OBJECTIVE: Vehicle safety rating systems aim firstly to inform consumers about safe vehicle choices and, secondly, to encourage vehicle manufacturers to aspire to safer levels of vehicle performance. Primary rating systems (that measure the ability of a vehicle to assist the driver in avoiding crashes) have not been developed for a variety of reasons, mainly associated with the difficult task of disassociating driver behavior and vehicle exposure characteristics from the estimation of crash involvement risk specific to a given vehicle. The aim of the current study was to explore different approaches to primary safety estimation, identifying which approaches (if any) may be most valid and most practical, given typical data that may be available for producing ratings. METHODS: Data analyzed consisted of crash data and motor vehicle registration data for the period 2003 to 2012: 21,643,864 observations (representing vehicle-years) and 135,578 crashed vehicles. Various logistic models were tested as a means to estimate primary safety: Conditional models (conditioning on the vehicle owner over all vehicles owned); full models not conditioned on the owner, with all available owner and vehicle data; reduced models with few variables; induced exposure models; and models that synthesised elements from the latter two models. RESULTS: It was found that excluding young drivers (aged 25 and under) from all primary safety estimates attenuated some high risks estimated for make/model combinations favored by young people. The conditional model had clear biases that made it unsuitable. Estimates from a reduced model based just on crash rates per year (but including an owner location variable) produced estimates that were generally similar to the full model, although there was more spread in the estimates. The best replication of the full model estimates was generated by a synthesis of the reduced model and an induced exposure model. CONCLUSIONS: This study compared approaches to estimating primary safety that could mimic an analysis based on a very rich data set, using variables that are commonly available when registered fleet data are linked to crash data. This exploratory study has highlighted promising avenues for developing primary safety rating systems for vehicle makes and models.

Home modifications to reduce injuries from falls in the home injury prevention intervention (HIPI) study: a cluster-randomised controlled trial.

BACKGROUND: Despite the considerable injury burden attributable to falls at home among the general population, few effective safety interventions have been identified. We tested the safety benefits of home modifications, including handrails for outside steps and internal stairs, grab rails for bathrooms, outside lighting, edging for outside steps, and slip-resistant surfacing for outside areas such as decks and porches. METHODS: We did a single-blind, cluster-randomised controlled trial of households from the Taranaki region of New Zealand. To be eligible, participants had to live in an owner-occupied dwelling constructed before 1980 and at least one member of every household had to be in receipt of state benefits or subsidies. We randomly assigned households by electronic coin toss to either immediate home modifications (treatment group) or a 3-year wait before modifications (control group). Household members in the treatment group could not be masked to their assigned status because modifications were made to their homes. The primary outcome was the rate of falls at home per person per year that needed medical treatment, which we derived from administrative data for insurance claims. Coders who were unaware of the random allocation analysed text descriptions of injuries and coded injuries as all falls and injuries most likely to be affected by the home modifications tested. To account for clustering at the household level, we analysed all injuries from falls at home per person-year with a negative binomial generalised linear model with generalised estimating equations. Analysis was by intention to treat. This trial is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12609000779279. FINDINGS: Of 842 households recruited, 436 (n=950 individual occupants) were randomly assigned to the treatment group and 406 (n=898 occupants) were allocated to the control group. After a median observation period of 1148 days (IQR 1085-1263), the crude rate of fall injuries per person per year was 0.061 in the treatment group and 0.072 in the control group (relative rate 0.86, 95% CI 0.66-1.12). The crude rate of injuries specific to the intervention per person per year was 0.018 in the treatment group and 0.028 in the control group (0.66, 0.43-1.00). A 26% reduction in the rate of injuries caused by falls at home per year exposed to the intervention was estimated in people allocated to the treatment group compared with those assigned to the control group, after adjustment for age, previous falls, sex, and ethnic origin (relative rate 0.74, 95% CI 0.58-0.94). Injuries specific to the home-modification intervention were cut by 39% per year exposed (0.61, 0.41-0.91). INTERPRETATION: Our findings suggest that low-cost home modifications and repairs can be a means to reduce injury in the general population. Further research is needed to identify the effectiveness of particular modifications from the package tested. FUNDING: Health Research Council of New Zealand.

An analysis of changes in mobility and safety of older drivers associated with a specific older driver on-road licensing test: a population study.

BACKGROUND: From 1999 to the end of 2006, older drivers aged 80 plus in New Zealand were subject to an older driver licence test as a condition of licensing. The impact of this test has not yet been studied in terms of the safety and mobility of older people. METHODS: Three main data sources were analysed to provide evidence of changes in older driver travel mode choice, licensing rates and injuries: New Zealand Travel Survey data, licensing data and police-reported crash data. RESULTS: General trends towards higher levels of motorised mobility were apparent for this group over the 20 years studied, but without an obvious change at the points in time when the test was either introduced or removed as a general requirement of licensure. There were also no apparent changes in the levels of pedestrian activity or road injury involving drivers in this age group. CONCLUSIONS: Along with other relevant studies comparing older driver licensing policies across different jurisdictions, this study does not support the generalised use of on-road testing as an assessment mechanism for all older drivers.

An evaluation of costs and benefits of a vehicle periodic inspection scheme with six-monthly inspections compared to annual inspections.

Although previous research suggests that safety benefits accrue from periodic vehicle inspection programmes, little consideration has been given to whether the benefits are sufficient to justify the often considerable costs of such schemes. Methodological barriers impede many attempts to evaluate the overall safety benefits of periodic vehicle inspection schemes, including this study, which did not attempt to evaluate the New Zealand warrant of fitness scheme as a whole. Instead, this study evaluated one aspect of the scheme: the effects of doubling the inspection frequency, from annual to biannual, when the vehicle reaches six years of age. In particular, reductions in safety-related vehicle faults were estimated together with the value of the safety benefits compared to the costs. When merged crash data, licensing data and roadworthiness inspection data were analysed, there were estimated to be improvements in injury crash involvement rates and prevalence of safety-related faults of respectively 8% (95% CI 0.4-15%) and 13.5% (95% CI 12.8-14.2%) associated with the increase from annual to 6-monthly inspections. The wide confidence interval for the drop in crash rate shows considerably statistical uncertainty about the precise size of the drop. Even assuming that this proportion of vehicle faults prevented by doubling the inspection frequency could be maintained over the vehicle age range 7-20 years, the safety benefits are very unlikely to exceed the additional costs of the 6-monthly inspections to the motorists, valued at $NZ 500 million annually excluding the overall costs of administering the scheme. The New Zealand warrant of fitness scheme as a whole cannot be robustly evaluated using the analysis approach used here, but the safety benefits would need to be substantial--yielding an unlikely 12% reduction in injury crashes--for benefits to equal costs.

Formulating a programme of repairs to structural home injury hazards in New Zealand.

Home injuries are a substantial health burden worldwide, with the home setting being at least as important as the road for injury. Focusing on common injury hazards presented by the home environment, we sought to examine the justification for significant expenditure on safety-related repairs to the housing stock. Trained inspectors assessed 961 New Zealand houses for injury hazards. Using administrative data from the Accident Compensation Corporation (the national injury insurance agency), 1328 home injuries were identified amongst the 1612 occupants of these houses over the 2006-2009 period. Telephone interviews gathered data on the location and nature of these injuries, and the attitudes of those injured to potential injury hazards in their homes. Commonly occurring injury hazards that could be repaired at modest cost were identified based on their prevalence estimated by the housing inspection, and their location with respect to the areas of the home where the injuries occurred (identified during the telephone interviews). About 38% of the home injuries studied were potentially related to a structural aspect of the home environment. Common safety hazards included the lack of working smoke detectors (65% of the sample), inadequately fenced driveways (55%), hot water temperatures measured at over 60° (49%) and poorly lit access to the house (34%). A protocol for identifying and repairing important common hazards was designed. The actual safety effects of this protocol are in the process of being examined in a randomised controlled trial.

Who can best influence the quality of teenagers' cars?

OBJECTIVE: Because young drivers' vehicles have been found to offer poor occupant protection in many countries, this study sought to identify the most appropriate audience for information and publicity designed to change purchasing preferences to improve these vehicles and resultant injury outcomes. METHODS: An analysis of New Zealand vehicles crashed by drivers aged 19 years or less linked to data on the owner of the vehicle was undertaken. Details on the crashed vehicles were merged with licensing information to identify the owner's age group. RESULTS: It was presumed that most vehicles driven by teens but owned by someone aged 30 to 59 would be owned by a parent of the teen. Only 14 percent of vehicles crashed by teens were owned by teens. Generally, older vehicles with poor crashworthiness were provided for the teenage driver, whatever the age group of the owner. However, cars crashed by teens but owned by their parents were on average almost 2 years younger and had relatively superior crashworthiness than the teenager-owned and crashed vehicles, although their crashworthiness was still poor compared to vehicles driven by older drivers. CONCLUSIONS: Evidently, parents are key people in making vehicle purchasing decisions regarding the cars that teenagers drive and should be the main audience for measures to improve the poor secondary safety performance of teenagers' vehicles.

The potential effectiveness of young driver high-performance vehicle restrictions as used in Australia.

Young drivers persistently have higher crash rates despite various countermeasures targeted at their risk factors and exposures. A potentially high risk situation for novice drivers may feasibly include the driving of high performance vehicles, which are subject to restrictions for probationary and restricted drivers in four Australian States. High performance vehicles are capable of high levels of acceleration and speed, which may encourage unsafe driving behaviours, particularly when driven by novice drivers, who may lack appropriate judgement and experience. This research sought to identify potential safety benefits of restrictions on certain vehicles for novice drivers using crash data from Australia and New Zealand, and vehicle licensing data from New Zealand. Data on crashed vehicles and their drivers were analysed to estimate the prevalence of the high performance vehicles in the fleets considered, particularly when driven by young people. By matching New Zealand licensing data with crash data, it was possible to estimate the risk of these high performance vehicles relative to other vehicles in the fleet. For owners aged under 25, a statistically significant 69% elevated injury crash involvement risk ratio was estimated for the high performance vehicles subject to restrictions in Australia in comparison with their risk with other vehicles controlling for other relevant factors (with 95% CI 30-123%, using owners aged 40-59 as a comparison group). Injuries in the vehicles of young owners of high performance vehicles were estimated to increase compared to their rate in other vehicles by 101% (with 95% confidence interval 69-171%, using owners aged 40-59 as a comparison group). Despite the higher relative risk for the high performance vehicles, they were relatively rare in the fleets studied, and the potential reduction in young driver injury rates from banning these vehicles was estimated to range from 0.4% in New Zealand to 2.5% in the Australian States of Queensland and Victoria. In addition, the potential reductions estimated here also depend on unrealistic assumptions of 100% compliance with regulation and the adoption of less risky driving behaviour in response to lower performance vehicles. Although these vehicles have a statistically significantly higher crash and injury risk than other vehicles when owned by young people, there are considerable costs of implementation and ongoing enforcement in imposing vehicle restrictions for young drivers that may not outweigh these potential safety benefits.

A preliminary estimation of motorcyclist fatal injury risk by BAC level relative to car/van drivers.

OBJECTIVE: This study sought to quantify the fatal injury risks for motorcyclists associated with the riders' blood alcohol concentrations (BACs). METHOD: Using a case-control study design with New Zealand data, fatal injury risk curves for motorcyclists and car drivers were modeled. A total of 142 fatally injured drivers/riders (cases) and 58,000 control drivers/riders were studied. For motorcyclists, there were 13 cases and 194 controls. RESULTS: The rate of increase in fatal injury risk with increasing BAC was not found to be different for motorcyclists compared to car/van drivers. However, because the baseline risk for motorcyclists was already considerably higher than for car/van drivers, even modest amounts of alcohol were associated with very high risks for motorcyclists compared to sober car/van drivers. It was estimated that, relative to their sober risk, motorcycle riders at BAC = 0.03 percent have 3 times the fatality risk (95% confidence interval [CI] = 2.8-3.5) and, at BAC = 0.08, 20 times the fatality risk (95% CI = 15.0-27.3). CONCLUSIONS: Interventions focused on reducing the alcohol consumption of motorcycle riders are clearly required when the degree of risk even at low alcohol levels is as disturbingly high as estimated in the current study.

Analysis of factors that increase motorcycle rider risk compared to car driver risk.

As in other parts of the Western world, there is concern in New Zealand about increasing popularity of motorcycles because of potential increases in road trauma. This study sought to identify important factors associated with increased risk for motorcyclists to inform potential policy approaches to reduce motorcyclist injury, such as changes to motorcyclist licensing, training and education. Using data extracted from a register of all New Zealand licensed motor vehicles that were matched to crash data, statistical models were fitted to examine patterns of motorcycle risk in comparison with small cars. These showed generally elevated risks for motorcyclists compared to cars, but particularly elevated risks for motorcycle owners aged in their 20s or who lived in more urbanised settings. In crashes, motorcyclists have little protection from injury, putting the motorcyclist at high risk of injury. When comparing new motorcycles with new cars, the odds of fatal or serious injury to a motorcycle rider involved in an injury crash were almost eight times the odds for a car driver.

A measure for quantifying the impact of housing quality on respiratory health: a cross-sectional study.

BACKGROUND: Damp and mould in homes have been established as risk factors for respiratory health. There is a need for a relatively straightforward assessment of the home that quantifies this risk. METHODS: Using data from 891 New Zealand houses, the utility of a Respiratory Hazard Index quantifying key attributes related to damp and mould was tested by studying its associations with self-reported respiratory symptoms. RESULTS: A dose-response relationship was found whereby each unit increase in the Respiratory Hazard Index was associated with an 11% increase in the odds of at least one episode of wheezing/whistling in the chest over the last 12 months (relative odds of 1.11 with a 95% CI 1.04%-1.20%). An 11% increase in the odds of an asthma attack over the last 12 months was estimated (relative odds of 1.11 with a 95% CI 1.01%-1.22%). These estimates were adjusted for household crowding levels, age, sex and smoking status. There was suggestive evidence of more steeply increasing odds of respiratory symptoms with increasing levels of the Respiratory Hazard Index for children aged under 7. In the worst performing houses according to the Index, a 33% reduction in the number of people experiencing respiratory symptoms (relative risk 0.67 with 95% CI 0.53 to 0.85) could be expected if people were housed in the best performing houses. CONCLUSIONS: This study showed that increased evidence of housing conditions supporting dampness and mould was associated with increased odds of respiratory symptoms. A valid housing assessment tool can provide a rational basis for investment in improved housing quality to improve respiratory health.

Injuries associated with housing conditions in Europe: a burden of disease study based on 2004 injury data.

BACKGROUND: The authors recently undertook a study for the World Health Organization estimating the European burden of injuries that can be attributed to remediable structural hazards in the home. Such estimates are essential for motivating injury prevention efforts as they quantify potential health gains, in terms of injuries prevented, via specific environmental interventions. METHODS: We combined exposure estimates from existing surveys and scenarios with estimates of the exposure-risk relationship obtained from a structured review of the literature on injury in the home and housing conditions. The resulting attributable fractions were applied to burden of injury data for the WHO European Region. RESULTS: This analysis estimated that two specific hazards, lack of window guards at second level and higher, and lack of domestic smoke detectors resulted in an estimated 7,500 deaths and 200,000 disability adjusted life years (DALYs) per year. In estimating the environmental burden of injury associated with housing, important deficiencies in injury surveillance data and related limitations in studies of injury risk attributable to the home environment were apparent. The ability to attribute proportions of the home injury burden to features of the home were correspondingly limited, leading to probable severe underestimates of the burden. CONCLUSIONS: The burden of injury from modifiable home injury exposures is substantial. Estimating this burden in a comprehensive and accurate manner requires improvements to the scope of injury surveillance data and the evidence base regarding the effectiveness of interventions.

Rating the overall secondary safety of vehicles from real world crash data: the Australian and New Zealand Total Secondary Safety Index.

Various systems for rating secondary safety of particular makes and models of vehicles have been developed internationally. These measures generally evaluate crashworthiness (the ability of the vehicle to protect its own occupants in the event of a crash) separately from aggressivity (the harm a vehicle is liable to impose on other road users into which it crashes). This paper describes an approach using Australian and New Zealand data that combines these two facets of secondary safety into one 'Total Secondary Safety Index' estimated from real world crash outcomes. The Index estimates the risk of death or serious injury to all key road users in crashes involving light passenger vehicles across the full range of crash types. This paper describes the rationale and method for producing this Index, together with some estimates for common Australian and New Zealand makes and models of light passenger vehicles.

Passenger vehicle safety in Australasia for different driver groups.

Vehicle fleets in developed countries have benefitted from improved technology and regulation leading to safer vehicles. Nevertheless, for various reasons the public do not necessarily choose particular makes and models of cars according to their safety performance. This study aimed to identify areas for potential crashworthiness improvement in the Australasian fleets by studying the distribution of these fleets according to vehicle age and estimated crashworthiness. We used an existing database that encompassed the vast majority of the crash fleets studied, with existing estimates of crashworthiness generated by the Australasian Used Car Safety Ratings project. There were clear tendencies for older and younger people to be driving less safe vehicles that were also generally older. Given that older drivers are more fragile, and hence more liable to be injured in crashes, and younger drivers have a greater propensity to crash, it is clearly undesirable that these driver groups have the least crashworthy vehicles. Some suggestions are made to encourage safer vehicle choices.

Estimation of the social costs of home injury: a comparison with estimates for road injury.

Home injury is thought to constitute a major health burden in most developed countries. However, efforts to address this burden have been hampered by reluctance from outside agencies to interfere with the home environment of individuals, even if it benefits the occupant's safety. This paper outlines cost-benefit evaluation methods established in the transport safety domain applied to home safety to estimate the social cost of unintentional home injury in New Zealand. Estimates of costs imposed on society by home injury can provide an important motivator for initiating research and programmes to reduce home injury risk. Data sources used included mortality data, hospitalisation data and data on minor injuries that required medical treatment, but not hospital admission. We estimated that unintentional home injuries in New Zealand impose an annual social cost of about $NZ 13 billion (about $US 9 billion), which is about 3.5 times the annual social cost of road injury. These estimates provide a rational evidence base for decisions on housing-focused safety regulation or interventions that always carry some cost, and therefore need to be weighed against the benefits of injuries potentially prevented.

Attitudes towards current and lowered speed limits in Australia.

The present study was concerned with gaining a greater understanding of the Australian community's attitudes towards both the current and proposed lower speed limits. An online survey was administered in four states (Victoria, South Australia, Western Australia, and Tasmania), with a total of 4100 respondents recruited. The survey focussed on attitudes towards speed limits for four different road types, and the sample was stratified according to age, gender, and area of residence. It was found that most respondents were able to correctly identify the speed limit for local residential streets and major urban arterials, although their knowledge of rural speed limits was considerably lower. The majority of respondents were in favour of the proposed lower speed limits on 100 km/h two-lane undivided rural roads and on rural gravel roads, but only about one-third supported lower limits in urban areas. A cluster analysis revealed that there were varying characteristics between respondents who were more or less likely to support speed limit reductions, across a number of demographic, socio-economic status, and driving behavior variables. These results provided important guidance regarding groups that could potentially be targeted in speed-related interventions, as well as highlighting the potential for lowering speed limits in Australia, particularly on rural roads.