Why we need a new access regime
The Department of Transport and Main Roads (TMR), as responsible road managers, needs to effectively meet regulatory and legislative requirements and facilitate heavy vehicle access in a way that is safe and sustainable for all road users.
The department has identified several factors that are driving the need for a new access regime for Class 1 heavy vehicles.
Queensland bridges not designed for current freight use
Our road network includes over 3,100 bridges ranging in age from 100 years old to recently constructed. Although we constantly improve our network to keep pace with bridge design standards and the modern vehicle fleet, some of our bridges were designed and built before the modern Class 1 fleet existed which means they are not designed for the task to carry these vehicles and have a finite load carrying capacity.
About half of our bridge network was designed for a 3 axle 33 tonne truck or less and about 15% (500) of our bridges are built to current engineering design standards which have been in place over the past 20 years. This equates to a new bridge being constructed every 2 weeks.
Class 1 vehicles including low loaders, load platforms and special purpose vehicles represent less than 1% of all heavy vehicle movements on our state-controlled road network. Yet from a structural engineering perspective they pose the greatest risk to our road and bridges due to their higher mass and concentrated load configuration.
We've undertaken extensive research to understand the risks associated with loads our bridges can support relative to their respective bridge design standards to help us understand how far we can continue to safely 'sweat our assets'. Our research has revealed the current access regime allows access for some Class 1 heavy vehicles beyond the assessed capacity of our bridges.
Now that we have a better understanding of how far we can push our assets safely and sustainably, we are using this as the basis for heavy vehicle access moving forward.
Changed industry vehicle choices and loading behaviour
The current Class 1 vehicle access regime was established in 1987 and like most states, it was based on allowable mass tables developed using 1970's engineering. Since this time there have been significant developments in the type of Class 1 vehicles, as well as industry vehicle choice and loading behaviour.
Many of the Class 1 vehicles that are operating today did not exist in the 1980s, or were very rare and only made infrequent trips, when the current access regime was first developed.
Demand for movements of large loads in Queensland is growing especially in the mining sector and in renewable energy infrastructure projects. In many cases, Class 1 vehicles are not operated over bridges as designed (such as in-lane travel instead of centre-line travel) and indivisible loads are not made truly indivisible.
Limitations of the current heavy vehicle access regime
The current permit application and approval processes:
- can be slow and time intensive, impacting permit approval timeframes and business opportunities for industry operators
- has limited certainty and visibility of access and mass limits, which inhibits industry operators' ability to plan movements with confidence
- has a lack of network usage visibility (vehicles, mass, and structure crossings) to inform asset and access management, and investment decisions.
Additionally, access conditions and restrictions on the road network can be:
- inconsistent throughout Queensland
- not easily accessible or understood by industry operators.