9210.0.55.001 - Survey of Motor Vehicle Use: Data Cubes, Australia, 12 months ended 31 October 2002
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 15/10/2003
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INTRODUCTION
The revised estimates from the 1998 SMVU and the 1999 SMVU have been produced by employing post-stratification to correct for population frame deficiencies. Detail on this process can be found in Technical Note 2: Methodological Review. SCOPE The scope of the survey (including the revised estimates from the 1998 and 1999 surveys) is all vehicles that were registered with a motor vehicle authority for road use at some stage during the 12 months ending 31 July 1998, the 12 months ending 31 July 1999 and the 12 months ended 31 October 2002. Not included are caravans, trailers, tractors, plant and equipment, vehicles belonging to the defence services and vehicles with diplomatic or consular plates. Where they were registered as such, vintage and veteran cars were also excluded from the survey. The population was identified using information obtained from the state and territory motor vehicle registration authorities. METHODOLOGY 2002 SMVU The data were collected in four quarterly sample surveys conducted by the Australian Bureau of Statistics (ABS) over the period 1 November 2001 to 31 October 2002. For the 2002 SMVU, a sample of approximately 16,700 vehicles was selected to report on vehicle use over a three-month period within the reference year 1 November 2001 to 31 October 2002. Of these, 24% were passenger vehicles and motor cycles, 60% were freight vehicles, 11% were buses and 5% were other non-freight carrying vehicles. The sample size was chosen to give a suitable level of precision for estimates of total distance travelled and tonne-kilometres for each state/territory of registration by type of vehicle category. The survey methodology is described as pre-advice, where owners of vehicles selected in the survey received early advice about their inclusion to encourage record keeping and minimise reliance on recall. These owners were asked to complete two mail questionnaires tailored to their vehicle type. The first, at the beginning of each quarterly survey period, asked for selected vehicle characteristics and the vehicle's odometer reading. Owners were also advised that they would receive a follow up questionnaire at the end of the quarter seeking details about the use of the vehicle over the quarter and a second odometer reading. Examples of the main items requested in the second questionnaire were included with the first questionnaire. When questionnaires were returned to the ABS they were checked for completeness and accuracy and, where possible, follow-up contact was made with owners to resolve reporting problems. Where contact with providers could not be made, missing items on incomplete questionnaires were filled by imputing average data from like vehicles for which data were obtained. Where the selected vehicle owner had not owned the vehicle for the whole quarterly survey period, the details provided for the period of ownership were adjusted to give a three-month equivalent, except where the vehicle was deregistered, in which case only the use up to the date of deregistration was included. In addition, adjustments were made in the estimation process to account for the use of new motor vehicles registered after the survey population was identified, as well as the re-registration of other vehicles during this time. More information about these adjustments is provided in Technical Note 1: Data Quality. Estimates from information reported in each quarterly collection period were produced and these were then aggregated into annual estimates relating to the use of vehicles during the period 1 November 2001 to 31 October 2002. The size of the sample is insufficient to produce reliable quarterly results. RELIABILITY OF ESTIMATES When interpreting the results of a survey it is important to take into account factors that may affect the reliability of estimates. Such factors can be classified as either sampling error or non-sampling error. Information on sampling and non-sampling error is provided in Technical Note 1: Data Quality. COMPARISON WITH MOTOR VEHICLE CENSUS DATA Survey estimates of the numbers of vehicles, by vehicle type, are not fully comparable with ABS Motor Vehicle Census data (see Motor Vehicle Census Australia, cat. no. 9309.0). The main differences are:
CONCEPT OF AVERAGES Many of these tables present data as averages. For all average distance tables except table 12 and all average tonne-kilometres tables, the denominator used in calculating these averages is the estimated number of vehicles that contributed to a particular cell. Table 12 presents average kilometres travelled per vehicle for all registered vehicles including those that travelled zero kilometres. The other tables present more detailed information on actual vehicle use where the denominator used in calculating the average is limited to the estimated number of vehicles that contribute to the particular cell. For example, in table 6 the average kilometres travelled for business purposes in Australia by passenger vehicles was derived by dividing the number of kilometres travelled for business purposes by passenger vehicles by the number of passenger vehicles which reported business travel. In tables 2, 10 and 15 the average rate of fuel consumption for each category is calculated by dividing the total fuel consumption by total kilometres. As the denominators used to calculate the cells of a table are different, the averages along a row cannot be used to derive the total column entry for that row. HISTORICAL COMPARISONS Care should be taken in drawing inferences from changes in data over time as movements may be subject to high RSEs and hence the changes may not be statistically significant. RELATED PUBLICATIONS AND PRODUCTS Users may also wish to refer to the following publications and products which contain information relating to motor vehicles in Australia: Motor Vehicle Census, Australia cat. no. 9309.0 - issued annually from 1995 Sales of New Motor Vehicles, Australia, (Electronic Publication) cat. no. 9314.0.55.001 - issued monthly Directory of Transport Statistics, 1998 cat. no. 1132.0 - released in January 1999 Transport Theme page on ABS Internet site. ABS DATA AVAILABLE ON REQUEST As well as the statistics included in this publication, the ABS has other relevant data available on request. Inquiries should be made to the National Information and Referral Service on 1300135070. Document Selection These documents will be presented in a new window.
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