Light vehicle seat or seating capacity alterations
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This page provides information on altering the seating capacity in a light vehicle — 4.5 tonnes gross vehicle mass(GVM) or less — by replacing seats, the addition of more seats, or the removal of the existing seats. It is not intended to cover every technical aspect of modifications but provides a brief overview.
Seating alterations on heavy vehicles must be certified by recognised engineering signatories (RES) as per VSB6 under Heavy Vehicle National Law. Refer to the National Heavy Vehicle Regulator website at nhvr.gov.au.
Before making any seating alterations or modifications and booking a seating inspection, incorporating roadworthy inspection, contact Vehicle Standards on 1300 882 248.
If the alteration contravenes the Australian Design Rules (ADRs) or the South Australian Road Traffic Act 1961 and its Regulations, it requires approval from the Vehicle Standards section of the Department for Infrastructure and Transport (DIT).
Altering the seating capacity or seating modification of a motor vehicle requires completing an Application to modify a light motor vehicle, issue of a statement of requirements (SoR) by the Vehicle Standards section, and may require an assessment by a light vehicle engineering signatory (LVES) and a roadworthy inspection, incorporating seating inspection.
Seats are classified into three categories as they are designed for occupants of different sizes and mass.
Category 1 - Seats capable of being used by adults.
Category 2 - Seats suitable for children approximately 4 to 12 years of age and capable of accommodating a child restraint.
Category 3 - Seats suitable for children approximately 4 to 7 years of age and not capable of accommodating a child restraint.
Category 2 and 3 seats may have shoulder height markers on the seat, identifying whether the seat is suitable for an occupant. If a person’s shoulder height is outside of the upper and lower range indicated on the seat, it must not be used. Where shoulder height markers are not present, a plate or label made of durable material identifying the seat category must be fitted in a conspicuous place on or near the seat.
Design, construction, and installation requirements
Category 1 seats must comply with the relevant Australian Design Rules that apply to the vehicle the seats are intended to be installed in.
Vehicle Standards Bulletin (VSB) 5 – Manufacture and Installation of Seats provides a nationally agreed set of requirements for the design, construction and installation of category 2 and 3 seats. VSB 5 is available on the Department of Infrastructure, Transport, Regional Development, Communications and the Arts website.
Original seats installed by the vehicle manufacturer fitted with integrated seatbelts, airbags, seat position sensors, or active head restraints shall only be replaced with seats with identical fittings, safety systems, and crash performance. They must not be replaced with aftermarket seats lacking these features.
Seating capacity alteration requiring an assessment by an LVES
The following seating alterations may require an assessment by an LVES:
- installing additional seats not offered as an option by the vehicle manufacturer at the time of the first registration
- modifying the structure or mounting of the original seats
- reupholstering seats that incorporate airbag systems
- replacement of original seats with aftermarket seats
- repositioning of seats and seat belts installed by the vehicle manufacturer at the time of first registration
- changing of seating capacity that results in the change of vehicle ADR classification.
It is recommended that Vehicle Standards is consulted before undertaking modifications to a vehicle. This is to ensure that modifications are carried out in an appropriate manner and that the vehicle will be able to be certified upon completion.
The engineering report requested in the statement of requirements must be submitted to Vehicle Standards at least 5 days before the vehicle is booked and presented for the roadworthy inspection, incorporating seating inspection. to be checked and verified.
An LVES is to assess the modification and provide a report to address the following:
- Details of seating removed.
- Details of child restraint anchorage fitment.
- Details of changes to fitted seat belts and additional seat belts installed.
- Details of all applicable ADRs for the vehicle’s proposed ADR category.
- Certification that the modified vehicle meets the intent of all ADRs applicable to the vehicle for the month and year of its manufacture and that it is fit for purpose.
Note: Alterations to the seating capacity in vehicles manufactured before 1969 may not require Vehicle Standards approval provided that the seat structure and mounting are at least that of the original seat. If there is any doubt about the seat mounting or structure, an LVES or Vehicle Standards section should be consulted.
Replacing seats with optional seats provided by the vehicle manufacturer
Seats supplied as an option by the vehicle manufacturer may be fitted without the need for Vehicle Standards approval provided:
- number of seating positions and seat location does not change from the vehicle manufacturer’s design for the variant
- the seat is one supplied by the vehicle manufacturer as an option for that vehicle and requires no further modifications to the vehicle
- the original seat mountings are used
- appropriate seat belts are fitted.
Installation of Category 2 and 3 seats in accordance with VSB 5
Seats in these categories must be fitted in accordance with the manufacturer’s instructions by a suitably qualified person. The seat must comply with the requirements of VSB 5 and once installed, be permanently affixed with manufacturer and installer plates in accordance with VSB 5. An LVES should be consulted if instructions are not available or if there is any doubt about the installation's compliance, particularly if the seat to be installed has been removed from another vehicle.
Wheelchair accessible vehicles
Such seat alteration requires completing an Application to modify a light motor vehicle, issue of SoR by the Vehicle Standards section, an assessment by an LVES, and a roadworthy inspection, incorporating seating inspection.
Increased seating capacity
Additional category 1 adult seats fitted to a vehicle will often change the vehicle category from a goods-carrying vehicle (NA) to a passenger-carrying vehicle (MA, MB, or MC) which is generally subject to higher safety standards. A goods-carrying vehicle becomes a passenger-carrying vehicle when the total number of seating positions multiplied by 68kg is 50% or more of the vehicle’s load-carrying capacity.
If a new vehicle’s seating capacity is altered in this way before being registered for the first time, it must be certified as a new vehicle that has undergone a second stage of manufacture and is fitted with the second stage manufacture compliance plate before being presented for first registration at a Service SA Centre.
If a vehicle has already been registered and is converted to a passenger-carrying vehicle by fitting additional seats, an SoR, Vehicle Standards exemption, and passed roadworthy inspection certificate are required to ensure that the vehicle meets the applicable higher safety standards.
Complete an Application to modify a light motor vehicle before modifying the vehicle and receive the SoR from Vehicle Standards. When the installation is complete, the vehicle must be booked for a roadworthy inspection and presented with the SoR.
Notifying the Registrar when seats are added or removed
Based on the assessment of the seating modification of previously modified vehicles, modifiers are approved by DIT for the modification of a particular make and model of the vehicle.
When the modification is completed by approved modifiers (for which they have approval), modifiers issue the certificate of approval for it. The vehicle owner must notify ServiceSA of the change by submitting the approval certificate at the nearest ServiceSA centre as soon as possible.
Returning the vehicle to its original seating arrangement and vehicle category is permitted. This requires completing an Application to modify a light motor vehicle, issue an SoR by the Vehicle Standards section, and a roadworthy inspection, incorporating seating inspection. This may also require assessment by an LVES .
Contact Vehicle Standards
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Application to modify a light motor vehicle
Light vehicle engineering signatories