**GLOSSARY**

**Articulated trucks**

Motor vehicles constructed primarily for load carrying, consisting of a prime mover having no significant load carrying area, but with a turntable device which can be linked to one or more trailers.

**Attrition rate**

The estimated proportion of motor vehicles taken off the register since the previous MVC. The attrition rate is also referred to as the motor vehicle retirement or scrappage rate. The number of registration lapses is calculated by adding the total registrations at the earlier MVC to the number of new motor vehicle sales between the MVCs, and subtracting the total registrations at the later MVC. The attrition rate measures the number of registration lapses as a percentage of the total potential vehicle fleet, where the potential vehicle fleet is the number of registrations at the first MVC date plus the number of new motor vehicle sales between the two MVCs. To calculate the annualised attrition rate as a percentage apply the following formula:

where T1 is the number of registrations at the first time point, N1 is the number of new sales between the first and second time points, T2 is the number of registrations at the second time point and M is the number of months between the two time points.

**Average age of vehicle**

The estimated average age of registered motor vehicles in Australia. The age of a vehicle is defined as the number of years since it was first manufactured. The formulae below allow for the census being conducted on different months of the year. They also assume that vehicles are manufactured at a constant rate over the year, or three month period for the current year.

For vehicles manufactured in the current year:

Vehicle age = Reference month/24

For vehicles manufactured in previous years:
Vehicle age = Current year - Year of manufacture + (Reference month - 6)/12

The average age is then calculated as the sum of all vehicle ages divided by the total number of vehicles. Vehicles that have a year of manufacture unknown are excluded from calculations of average age.

**Buses**

Motor vehicles constructed for the carriage of passengers. Included are all motor vehicles with 10 or more seats, including the driver's seat.

**Campervans**

Self-propelled motor vehicles containing an area primarily used for accommodation. Included are motor homes and powered caravans.

**Estimated Resident Population (ERP)**

The official ABS estimate of the Australian population. Based on results from the Census of Population and Housing, it is updated annually between censuses using demographic statistics. To obtain ERP figures, the census count is adjusted for under enumeration and for Australian residents temporarily overseas on census night.

**Gross Combination Mass (GCM)**

Tare weight (i.e. unladen weight) of the motor vehicle and attached trailers, plus its maximum carrying and towing capacity. GCM is the weight measurement used for trailer towing vehicles such as articulated trucks.

**Gross Vehicle Mass (GVM)**

Tare weight (i.e. unladen weight) of the motor vehicle, plus its maximum carrying capacity excluding trailers.

**Heavy rigid trucks**

Rigid trucks of GVM greater than 4.5 tonnes.

**Light commercial vehicles**

Vehicles primarily constructed for the carriage of goods, and which are less than or equal to 3.5 tonnes GVM. Included are utilities, panel vans, cab-chassis and forward-control load carrying vehicles (whether four-wheel drive or not).

**Light rigid trucks**

Rigid trucks of GVM greater than 3.5 tonnes and less than or equal to 4.5 tonnes.

**Make**

The manufacturer of the motor vehicle (e.g. Ford, Holden, Mitsubishi, Toyota).

**Motorcycles**

Two and three wheeled motor vehicles constructed primarily for the carriage of one or two persons. Included are two and three wheeled mopeds, scooters, motor tricycles and motorcycles with sidecars.

**Non-freight carrying trucks**

Specialist motor vehicles or motor vehicles fitted with special purpose equipment, and having little or no goods carrying capacity (e.g. ambulances, cherry pickers, fire trucks and tow trucks).

**Passenger vehicles**

Motor vehicles constructed primarily for the carriage of persons and containing up to nine seats (including the driver's seat). Included are cars, station wagons, four-wheel drive passenger vehicles and forward-control passenger vehicles. Excluded are campervans.

**Rigid trucks**

Motor vehicles of GVM greater than 3.5 tonnes, constructed with a load carrying area. Included are normal rigid trucks with a tow bar, draw bar or other non-articulated coupling on the rear of the vehicle.

Rigid trucks are divided into two categories:

- Light rigid trucks of GVM greater than 3.5 tonnes and less than or equal to 4.5 tonnes
- Heavy rigid trucks of GVM greater than 4.5 tonnes.

**State/territory**

The state or territory of the motor registry at which a vehicle is registered.

**Statistical division (SD)**

The SD is a general purpose spatial unit and is the largest and most stable spatial unit within each state/territory. In aggregate they cover Australia without gaps or overlaps. SDs aggregate to form state/territories. For more information refer to **Australian Standard Geographical Classification (ASGC), 2005 (cat. no. 1216.0).**