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Zero Emission PBS Vehicles

By harnessing locally produced electric trailers and hybrid diesel-electric powertrains, we can bridge this gap and de-risk the introduction of low-emission high-productivity vehicles. Coupled with renewable diesel, this approach provides a promising, low-risk transition pathway for Australia’s bulk transport industries, particularly in mining, agriculture, and construction.


This policy proposal seeks to strengthen the PBS Vehicle Approval and Access Framework, offering strategic incentives to encourage operators to embrace reduced-emission, high-productivity vehicles. Our recommendations include key concessions and adjustments to ensure a smoother adoption of low-emission PBS combinations, ultimately paving the way for a complete shift to zero-emission PBS vehicles.

Here's how we propose to shape this future:


Axle Group Mass Limit Concessions:

Provide mass limit concessions for steer, drive, and trailer axle groups to incentivize operators to adopt low-emission PBS combinations.


  • Single steer axles: 9 tonnes

  • Twin-steer axle (load sharing): 14 tonnes

  • Tandem Axles: 20 tonnes

  • Tri-axles: 25 tonnes

  • Quad-Axles: 30 tonnes


Non-steer axle suspensions would require approved road friendly suspensions tested at the Low-Emission permit weight. By providing sufficient incentives to higher axle group weights, e.g. 30 tonnes per quad-axle group and 14 tonnes per twin steer, the weight per axle is likely to be equivalent to what is currently approved under Higher Mass Limits (e.g. 7.5 tonnes per dual tyre axle and 7 tonnes on the steer axle). The suggested concessional weights also align with axle group weights approved for Special Purpose Vehicles (SPVs). This brings the PBS Scheme in line with the concessions approved in countries like South Africa who base their PBS axle mass limits on those applied to SPVs.


Bridge Assessments:

Introduce bridge assessments for general freight using volumetric bridge load factors, facilitating the safe passage of larger, more efficient vehicles.

Increased Speed Limits for Reduced Emission Vehicles:

Adjustments to maximum speed limits for reduced-emission combinations to better reflect their advanced technological and performance capabilities. It also provides further investment incentives for operators who will benefit from reduced overall trip times:


• PBS Level 1: Up to 110 km/h

• PBS Level 2: Up to 100 km/h

• PBS Level 3: Up to 100 km/h

• PBS Level 4: Up to 100 km/h


Concessions for Multi-Axle Groups:

Remove the need for Section 8 exemptions for reduced-emission PBS combinations equipped with multiple-axle group trailers along them broader access on Tier 1 networks.


Length Limit Adjustments:

Greater length helps overcome bridge strength issues and provides more space to package Renewable Energy Storage Systems (RESS). We therefore propose the following length limits for low-emission PBS combinations:


  • PBS Level 1: Up to 23 meters (including general access up to 60 tonnes)

  • PBS Level 2A: Up to 30 meters

  • PBS Level 2B: Up to 36.5 meters

  • PBS Level 3A: Up to 42 meters

  • PBS Level 3B: Up to 45 meters

  • PBS Level 4A: Up to 60 meters

  • PBS Level 4B: Up to 65 meters


Eligibility Criteria:

A reduced-emission PBS combination must demonstrate at least 30% reduced diesel fuel consumption through hybrid battery-electric or hydrogen powertrains or use 100% renewable diesel. By 2030, these concessions might be exclusive to zero-emission PBS combinations.


Improved Performance and Higher Standards:

Zero-emission PBS combinations offer potential advantages in acceleration capability, maximum grade, speed on grade, and safe speeds downhill, leading to shorter trip times and reduced overall freight exposure. They are also likely to demonstrate improved high-speed stability and safety.

As these combinations become more prevalent, the PBS standards should be reviewed to increase the minimum safety requirements across all PBS combinations. This would provide further incentives for the shift to zero-emission PBS combinations and improve overall fleet safety and productivity.


Improved Safety Conditions:

To access these benefits, the combinations must be fitted with the latest technologies to enhance their compliance and safety. This includes GPS tracking with onboard mass monitoring to ensure route compliance and facilitate the move to mass-distance location charging, along with tyre pressure monitoring and enhanced fire protection systems.

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