The aim of this study was to profile registered vehicles and crash data from 2006-2012 for West Australian passenger vehicles by fleet type: metropolitan corporate, rural corporate, government and private. It also aimed to construct a model to project crashes and occupant injuries by road user for the 2012 registered cohort of new light passenger and commercial vehicles over 22 years as a baseline upon which to evaluate different fleet purchasing scenarios. Stage 1 of the study profiled WA passenger vehicle registrations from 2006 to 2012 and WA passenger vehicle crashes from 2006 to 2009. Government and corporate fleet vehicles in WA are becoming an increasing influence on the total make-up of WA registered passenger vehicles. Growth in registrations was not only observed for all vehicles, but this growth was been disproportionally greater for corporate and government fleet vehicles. From December 2008 to March 2012 the proportion of metropolitan corporate fleet vehicles grew from 7 to 12%, the proportion of rural corporate vehicles increased by 1% unit and the proportion that were government fleet vehicles more than doubled. With greater proportions of new government and corporate vehicles becoming registered, the average age of these vehicles was observed to decrease, so, newer and generally safer vehicles are trending to make up a larger proportion of the corporate and government fleets. However, a trend for increasing average age in rural corporate SUVs was observed, indicating that proportionally fewer new vehicles are entering this market group sector. In general, more aggressive market groups were held onto by the corporate fleet for longer periods. These trends result in potentially less safe light commercials and SUVs in corporate fleets; particularly in the rural corporate fleet. Government and corporate fleet vehicles in WA currently consist of greater proportions of vehicles from aggressive market groups compared to the private vehicle fleet. In March 2012, these SUVs and light commercial vehicles made up 61% of metropolitan corporate fleet vehicles and 76% of rural corporate fleet vehicles. In contrast, these market groups made up 52% of government passenger vehicle registrations and only 34% of private registrations. In 2012, new vehicles from aggressive market groups continued to be purchased in large proportions for the corporate and government fleets. The flow on effect of the more aggressive corporate and government fleet is that greater proportions of vehicles from aggressive market groups are entering the private fleet when they are transferred from corporate or government ownership. Thus the large proportions of aggressive market groups in the corporate and government fleets are not only a concern for fleet buyers, but also for society in general as these vehicles transfer to private ownership. When involved in crashes, higher aggressivity vehicles put the occupants of the other vehicle and unprotected road users at higher risks of serious injury. Thus, the large increasing proportions of more aggressive market groups in the corporate and government fleets is of concern because of the injury and cost of injury burden it places on society. Generally fleet buyers were found not to purchase the most crashworthy vehicles available within the market groups chosen. In metropolitan corporate fleets the most crashworthy model in 2012 amounted to 7% of utility, 6% of van 16% of large vehicle, 0.05% of medium vehicle, 0.1% of small vehicle, 11% of light vehicle, 73% of people mover, 3% of compact SUV, 1% of medium SUV and 9% of large SUV purchases. With the exception of people movers, there was significant room for improvement in the safety of fleet vehicles purchased. Corporate and government fleet vehicles experienced a substantially higher crash risk per registered vehicle than private vehicles in WA over the 2006-2009 period, despite most corporate and government fleet drivers being over 25 years of age and despite most corporate vehicles being newer and thus more likely to be fitted with newer safety technology. The observed higher crash risk per registered vehicle is most likely due to greater travel exposure by corporate and government fleet vehicles compared to private vehicles in W.A. Metropolitan corporate utilities and vans pose a more serious crash risk to other road users than do privately owned utilities and vans, relative to the rest of their respective fleets. Metropolitan corporate, relative to private, vehicle crash risk was highest for utilities and vans. At 1.8, it was higher than the 1.5 times relative crash risk obtained for SUVs and other passenger vehicles. When comparing metropolitan corporate vehicle crashes to private vehicle crashes by crash type and broad market group, metropolitan corporate utilities and vans were found to be more likely to be in a rear-end crash, more likely to be in a crash with a heavy vehicle, more likely to be in a fatal and serious injury crash and more likely to be in a fatal and serious injury head on crash. Driver injuries in rural corporate crashes are more likely to be serious than for metropolitan corporate or private injury crashes. Because of the more aggressive composition of corporate and government fleets, they do not pose a higher risk of any driver injury compared to the private fleet. However, once a driver injury is reported, the risk of the driver injury serious or fatal tended to be greater in the rural corporate fleet than in the metropolitan corporate or private fleets. Rural corporate SUVs, vans and utilities had a higher percentage of roll-over crashes than their private counter parts. Rural corporate SUV vehicles were also overrepresented in head-on crashes and rural corporate vans and utilities were over represented in head-on fatal and serious crashes In comparison to the private SUV fleet metropolitan corporate SUVs were also over-represented in some crash types. They had a higher than expected percentage of roll-over crashes, proportionally more hit object crash types and were over-represented in crashes with heavy vehicles. Scenarios were considered to increase the proportion of more crashworthy vehicles or decrease the aggressivity of vehicles in government and corporate fleets. It was hypothesised that if WA corporate and government fleets consisted of proportionally fewer aggressive and/or more crashworthy vehicles, injury outcomes in crashes would improve. Scenarios were also proposed to evaluate crash reductions associated with increased uptake of Electronic Stability Control in light commercial vehicles and Side Curtain Airbag technology in all cars. Additional scenarios were evaluated considering increased uptake of new technologies that specifically targeted the most frequent crash types in WA. Forward collision warning systems with autonomous braking intervention were proposed to address rear-end collision types. Lane departure and fatigue warning systems were proposed to address out of control crashes such as single vehicle roll-overs and hit object crashes. Lane change/blind spot warning systems were proposed to address crashes from intentional lane changes such as side-swipes. Before proposed scenarios were evaluated, a baseline model was presented for 2012 registered vehicles projected over a 22 year life. Modelled crash numbers are a function of: i) the market groups of the 2012-registered vehicle cohort; ii) the current fleet status of the 2012-registered vehicle cohort; iii) the future fleet status of the 2012-registered vehicle cohort; iv) the future year of the crash; and v) the type of crash (whether it involves a risk of injury to the occupants of the 2012-registered vehicle only, other road users only, or both other road users and occupants of the 2012-registered vehicle); In addition to estimating the number of crashes, the model also allowed the estimation of the number of seriously injured road users that were injured in different types of crashes. This model was created using estimates of present fleet purchasing patterns and forecasts of scrapping rates and transfer rates to private ownership based on what has occurred in previous years. The model represents a baseline scenario of what role we would expect vehicles originally registered as fleet vehicles in 2012 to play in crash outcomes over their useful lives (the following 22 years). It was used to evaluate various alternatives in the composition and specification of the 2012 new vehicle cohort to see what effect they have on injury outcomes when compared to the status quo represented by the baseline scenario. The effect of modifying various model parameters according to the scenarios proposed to reflect various changes in vehicle fleet purchasing and management policies was investigated. Expected number of crashes and casualties at each severity level resulting from changes in these model inputs were then compared with the baseline scenario to calculate the relative benefits of various fleet purchasing and management policies. This model demonstrated that approximately half of the serious and fatal injuries, from crashes involving these vehicles over the 22 year period, could be attributed to occupants of the 2012 registered vehicle, the remainder being sustained by the collision partner. Approximately 70% of the proposed crashes were property damage-only crashes regardless of the vehicle’s original or current fleet type. The baseline model of the 2012 new vehicle fleet estimated a lifetime total of 5,635 crashes and 2,320 injured occupants from crashes involving vehicles that were originally metropolitan corporate fleet vehicles, 571 crashes and 235 injured occupants involving vehicles that were originally rural corporate fleet vehicles and 359 crashes and 147 injured occupants from crashes involving vehicles that were originally government fleet vehicles. These figures indicate the relative size of each fleet and hence the relative importance to overall road trauma. The present value total costs of these crashes to society were determined using a 4% discount rate and 2006 crash and injury costs from BITRE (2009) adjusted with the CPI to 2012 values. Approximately 14% of crash costs were attributable to property damage-only crashes and 16% of crash costs were attributable to the vehicle damage and general costs associated with injury crashes. The remaining 70% of costs were associated directly with the human costs of injuries to occupants and other road users involved in the crashes: 67% serious and fatal injury costs and 3% minor injury costs. Total crash costs amassed over the 22 years to $247 million dollars for vehicles that were originally metropolitan corporate and to $24 million for originally rural corporate vehicles and $15 million from vehicles that were originally registered to government. The efficacy of each scenario considered at reducing the present value of crash costs was directly related to its ability to reduce serious and fatal injuries since 67% of crash costs were attributable to the human cost of serious and fatal injuries and only 3% of crash costs were attributable to the human cost of minor injuries. Nine scenarios for changing the profile of the newly registered 2012 vehicle cohort in WA were considered: 1. Only purchasing the most crashworthy vehicle in each market group 2. Replacing the purchases of large and medium metropolitan SUVs with large vehicles and rural large SUVs with medium SUVs A. Using a fleet average vehicle for the market group B. Using the least aggressive model in the market group 3. Fitment of active forward collision detection and intervention operational at speeds of 80 km/h and greater 4. Fitment of active forward collision detection and intervention operational at all speeds 5. Fitment of fatigue warning systems 6. Fitment of lane departure warning systems 7. Fitment of lane change/blind spot warning systems 8. Fitment of Side Curtain Airbags (SCA) to models without SCA as standard 9. Fitment of ESC to utilities and vans without ESC as standard Table E1 summarises the results of the scenario modelling by fleet type. It gives both the present value of the total lifetime savings in community social costs associated with the 2012 vehicle fleet including savings in minor and non-injury crashes. It also gives the expected number of savings in deaths and serious injuries for the cohort over its lifetime and the community social costs specifically related to deaths and serious injuries. (Author/publisher)
Samenvatting