DSUB grandfathering examples in practice
DSUB grandfathering examples in practice
National
Heavy
Vehicle
Regulator
Scenario 1: Trailer replacement
A transport operator holds a PBS Vehicle Approval (VA) for a B-double. The prime mover and both trailers were included on the VA prior to 18 January 2027. Following this date, the rear semitrailer reaches the end of its life, and the operator purchases a replacement trailer, which they wish to include on the VA.
1a.
If the VIN of the newly purchased semitrailer has been listed on a PBS VA - not necessarily held by the transport operator or be for a B-Double combination - then the semitrailer is considered grandfathered and is not required to meet the revised DSUB requirements. No additional requirements apply to the existing prime mover or lead trailer.

1b.
If the VIN of the newly purchased semitrailer has never been listed on a PBS (i.e. brand new or never been used in a PBS combination), then the semitrailer must comply with the revised DSUB requirements. This includes the requirement for status indication. Since the rear semitrailer must have EBS, the prime mover and lead trailer need to be fitted with ABS/EBS connectors (ISO 7638). If they do not have this wiring, it must be retrofitted before the newly purchased semitrailer can be added to the VA.
Note: The ABS/EBS connectors in the existing prime mover and lead trailer do not need to include an electric control line, just the power, ground and fault indication wiring.

In both cases, a PBS certifier needs to certify the newly purchased trailer for it to be included on the VA. For scenario 1b, the certifier also needs to re-certify any grandfathered prime movers or lead trailers already on the VA to provide assurance that they meet the trailer connector requirements.
Scenario 2: Hauling unit replacement
A transport operator holds a PBS Vehicle Approval (VA) for a truck and dog. Both the truck and dog trailer were included on the VA prior to 18 January 2027. Following this date, the truck reaches the end of its life, and the operator purchases a replacement truck, which they wish to include on the VA.
2a.
If the VIN of the newly purchased truck has been listed on a PBS VA - not necessarily held by the transport operator, or be for a truck and dog combination - then the truck is considered grandfathered and is not required to meet the revised DSUB requirements.

2b.
If the VIN of the newly purchased truck has never been listed on a PBS VA (i.e. brand new or never been used in a PBS combination) then the truck must comply with the revised DSUB requirements. This includes the requirement for status indication. The truck must be fitted with an ABS/EBS connector (ISO 7638) and supply an electric control line even if the existing dog trailer is not fitted with an ABS or EBS system. This is required to ensure hauling units have the necessary technology if they are ever used with more advanced trailers.

In both cases a PBS certifier needs to certify the newly purchased truck for it to be included on the VA.
Scenario 3: Vehicle addition
A transport operator holds a PBS Vehicle Approval (VA) for a prime mover semitrailer combination. The operator wishes to add new prime movers and trailers to the VA after 18 January 2027.
3a.
If the VINs of the newly purchased vehicles have been listed on a PBS VA - not necessarily held by the transport operator or be for a prime mover-semitrailer combination - then the vehicles are considered grandfathered and are not required to meet the revised DSUB requirements.

3b.
If the VINs of the newly purchased vehicles have never been listed on a PBS VA - (i.e. brand new or never been used in a PBS combination) then the vehicles must comply with the revised DSUB requirements. This includes the requirement for status indication.

In both cases a PBS certifier needs to certify the newly purchased vehicles for them to be included on the VA. For scenario 3b, if the vehicle being added is a trailer, the certifier also needs to re-certify any grandfathered prime movers on the VA to provide assurance that they meet the trailer connector requirements.
Scenario 4: New PBS Vehicle Approval
A transport operator owns a truck and dog trailer and wishes to use them in the PBS scheme. The operator contacts a PBS certifier to obtain a new PBS Vehicle Approval (VA) after 18 January 2027.
4a.
If the VINs of the truck or dog trailer have been listed on a PBS VA - not necessarily held by the transport operator, be for a truck and dog combination or contain both the truck and dog trailer on the same VA - then the vehicles are considered grandfathered and are not required to meet the revised DSUB requirements.

4b.
If the VINs of the truck or dog trailer have never been listed on a PBS VA (i.e. brand new or never been used in a PBS combination) then the vehicles must comply with the revised DSUB requirements. This includes the requirement for status indication.

Scenario 5: Addition of an ‘identical VIN’
A transport operator owns a fleet of A-double combinations, which are all operating in the PBS scheme prior to 18 January 2027. They purchase a new rear semitrailer that has never been PBS certified. The manufacturer has prepared a declaration noting the trailer is identical and made in the same production run as the previous trailers.
Scenario 1b applies here. Being identical to grandfathered vehicles, even if produced in the same production run, does not change the need for the newly purchased trailer to comply with the revised DSUB requirements.
