EXPLANATORY NOTES


MOTOR VEHICLE CENSUS

1 This publication presents statistics relating to vehicles which were registered with a motor vehicle registration authority at 31 January 2011.

2 Motor Vehicle Censuses (MVC) have been conducted periodically from 1971 on each of the following dates:

2011, 31 January	1998, 31 October
2010, 31 March	1997, 31 October
2009, 31 March	1996, 31 October
2008, 31 March	1995, 30 May
2007, 31 March	1993, 30 June
2006, 31 March	1991, 30 September
2005, 31 March	1988, 30 September
2004, 31 March	1985, 30 September
2003, 31 March	1982, 30 September
2002, 31 March	1979, 30 September
2001, 31 March	1976, 30 September
1999, 31 October	1971, 30 September

SCOPE

3 The Motor Vehicle Census includes all vehicles registered with a state or territory motor vehicle registry for unrestricted use on public roads with the following exceptions:

• recreational vehicles such as trail bikes and sand dune buggies intended for off-road use in most states and territories (in Victoria and Queensland these vehicles must be registered and are thus included in the statistics);
• consular vehicles; and
• vehicles registered by the defence forces.

4 Vehicles on register are defined as those vehicles registered at the date of the census, or which had registration expire less than one month before that date. Data for Tasmania does not include vehicles which had registration expire less than one month before that date.

5 Motor vehicle registration statistics are derived from data made available by various state and territory motor vehicle registration authorities and reflect the information as recorded in registration documents.

6 Vintage and veteran vehicles are excluded from vehicle counts in the published data, but are available for consultancy data requests. These vehicles are identified using a unique insurance code, with the following exceptions:

• in New South Wales this insurance code is not provided and it is not possible to separately identify these vehicles. Therefore veteran and vintage vehicles are included in the number of registered vehicles for New South Wales.
• while Victoria does provide an insurance code for these vehicles, this insurance code also applies to tractors, motorcycles and self propelled farm machinery owned by primary producers and used solely in connection with the business of a primary producer. These records are deemed out of scope. (Note: tractors and motor cycles not used solely in connection with the business of a primary producer have a different insurance code which deems them in scope.) Therefore, the number of veteran and vintage vehicles cannot be obtained for Victoria.

7 The estimated proportion of motor vehicles, excluding motor cycles, taken off the register since the previous MVC is referred to as the attrition rate. The attrition rates in the following table have been calculated using Motor Vehicle Census and New Motor Vehicle Sales data. Motor cycles are excluded from the attrition rate calculation as they are not included in New Motor Vehicle Sales data.

Estimated Attrition(a)(b), State/territory - Census years
	Between 2006 and 2007		Between 2007 and 2008		Between 2008 and 2009		Between 2009 and 2010		Between 2010 and 2011
	no.	%	no.	%	no.	%	no.	%	no.	%
NSW	217 518	4.9	178 856	3.9	256 868	5.5	197 826	4.2	171 296	3.6
Vic.	179 505	4.6	178 750	4.5	176 676	4.4	165 499	4.0	152 483	3.6
Qld	97 337	3.2	107 629	3.4	105 556	3.3	135 271	4.1	127 418	3.8
SA	45 253	3.9	43 554	3.7	36 588	3.0	35 204	2.9	33 639	2.7
WA	46 866	2.8	61 171	3.5	38 675	2.2	68 840	3.7	61 357	3.3
Tas.	13 258	3.5	10 679	2.7	10 111	2.5	9 661	2.4	7 927	1.9
NT	5 649	4.7	5 983	4.8	4 761	3.7	4 034	3.0	6 042	4.4
ACT	r10 227	r4.3	10 554	4.4	11 073	4.5	9 206	3.7	8 567	3.4
Aust.	r615 613	r4.1	597 176	3.9	640 308	4.1	625 541	3.9	568 729	3.5
r revised
(a) Percentage change movements have been converted to an annual basis. See Glossary for further information.
(b) These estimates exclude motor cycles. For more details on calculation of attrition rate refer to Glossary.

METHODOLOGY

8 The 2011 Motor Vehicle Census is a count of all in-scope vehicles registered with a state or territory motor vehicle registration authority (MVR) at 31 January 2011. All records are compared to previous MVC data for vehicles that match (on-going registrations) and details are updated for these vehicles where applicable.

9 The unmatched records (new vehicle registrations) undergo editing of individual data items. The editing of on-going registrations is limited as these records have been edited in previous years. Aggregate data is checked across time, states and vehicle types to ensure coherency.


DATA QUALITY

10 The primary use of the MVC is as a frame for the Survey of Motor Vehicle Use (SMVU). Editing of the data is designed to maximise data quality to the level required for the SMVU. The size of the fleet (over 16 million vehicles) dictates that quality assurance of each record is not possible. Therefore, while the data are made available at a detailed level, the ABS is unable to guarantee that it is necessarily sufficient for all purposes for which it is used. There is also some variation in the reporting from different state and territory registries and care should be taken when comparing data across jurisdictions.

11 The information provided to the ABS and included in the estimates for any month may be revised or corrected in later months. Where corrections are made to original data they will be identified by the annotation (r) revised.


STATISTICAL GEOGRAPHY

12 Geographic data available from the MVC are postcode of owner and state or territory of registration.

13 If analysis of regional data based on postcodes is being undertaken, the following considerations need to be taken into account:

• there are some instances where the postcode of the vehicle's owner is in a different state or territory from that in which the vehicle was registered. For example, the postcode of the owner of the vehicle could be in Sydney, yet the vehicle could be registered in Queensland;
• some official postcodes (PO boxes, competition postcodes) do not correspond to residential areas;
• some postcodes could be invalid.

ACKNOWLEDGEMENT

14 This publication draws extensively on information provided freely by the state and territory motor vehicle registration authorities. Their continued cooperation is very much appreciated. Without it, many of the transport statistics published by the ABS would not be available.


RELATED PUBLICATIONS AND PRODUCTS

15 Users may also wish to refer to the following publications and products which contain information relating to motor vehicles in Australia:

• Sales of New Motor Vehicles, Australia, (Electronic Publication) cat. no. 9314.0 (issued monthly)
• Survey of Motor Vehicle Use, Australia cat. no. 9208.0
• Information Paper: Experimental Estimates of Motor Vehicle Use, 12 months ended 31 October 2008 cat. no. 9222.0

ABS DATA AVAILABLE ON REQUEST

16 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 1300 135 070.