9309.0 - Motor Vehicle Census, Australia, 31 Mar 2009 Quality Declaration 
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 17/11/2009   
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TECHNICAL NOTE 2 NSW


INTRODUCTION

1 Analysis undertaken during the preparation of the 2009 Motor Vehicle Census identified an apparent inaccuracy of the published number of registered vehicles for NSW in 2008. This Technical Note gives a brief description of this issue and provides revised estimated vehicle counts.


DATA QUALITY

2 In 2008, the count of vehicles initially recorded in NSW was lower than expected. Analysis of the data revealed an issue with registration expiry dates. A second file was later obtained from the NSW Motor Vehicle Registry and new vehicle counts were produced from this file.

3 The new data for NSW indicated an increase in the number of vehicles of 3.6% from 2007 to 2008. However, when compared with the vehicle count for 2009, there was only a 1.0% increase. This led to a re-examination of both the 2008 and 2009 vehicle counts.

4 To assist with the analysis of 2008 and 2009 data, the NSW Roads and Traffic Authority provided counts of vehicle numbers taken on the same date as the MVC snapshot for the past 5 years. These were used to confront the published MVC vehicle counts. Counts of vehicles from the registry closely matched those from the MVC in all years except 2008.

5 Revised estimates of vehicle numbers by vehicle type can be made by concording the vehicle type classifications used by the NSW Roads and Traffic Authority and the MVC. It is not possible to revise data at each classification level as unit record data cannot be recreated, hence tables 1 to 9 of this publication do not contain revised data.


ADJUSTED ESTIMATES

6 Revised estimates for 2008 NSW MVC data by vehicle type were created using the percentage difference between MVC and NSW Motor Vehicle Registry data over the past 5 years. A linear regression was calculated to describe the relationship between these data sets over the 5 year time period, and the expected difference for 2008 according to this regression was used to adjust the original MVC vehicle counts.

NSW Registrations, Type of vehicle - Census years

2007
Original 2008
Revised 2008
2009
Vehicle Type
'000
'000
'000
'000

Passenger vehicles
3 464
3 581
3 537
3 603
Light commercials
599
622
611
631
Light rigid trucks
34
36
35
37
Heavy rigid trucks
81
82
81
82
Articulated trucks
16
17
17
17
Non-freight vehicles
4
4
4
4
Campervans
9
9
9
9
Buses
21
22
22
22
Motorcycles
133
148
146
163
Total
4 361
4 520
4 461
4 567


Percentage change in number of registered motor vehicles

Original
Revised
07 to 08
08 to 09
07 to 08
08 to 09
Vehicle type
%
%
%
%

Passenger vehicles
3.4
0.6
2.1
1.9
Campervans
2.6
5.0
2.1
5.5
Light commercials
3.7
1.5
2.0
3.2
Light rigid trucks
4.3
2.9
2.5
4.7
Heavy rigid trucks
1.6
0.3
1.0
0.9
Articulated trucks
2.4
0.9
1.0
2.3
Non-freight trucks
-0.6
0.7
-0.6
0.7
Buses
4.3
3.4
4.0
3.7
Motor cycles
11.2
9.8
9.4
11.6
Total motor vehicles
3.6
1.0
2.3
2.4