When a road access application is received from the National Heavy Vehicle Regulator (NHVR) the Department for Infrastructure and Transport (DIT) Road Manager will undertake a desktop route assessment.
This assessment is used to determine if the road infrastructure meets the minimum standards on the NHVR website Performance Based Standards Scheme Network Classification Guidelines applicable to the heavy vehicle combination.
If the vehicle meets the minimum route assessment requirements, a field trial is not required, and access can be provided.
If the vehicle route assessment is inconclusive, a field trial may be considered.
Assessment criteria
A field trial is subject to Road Manager and if applicable, third party entity consent. For more information on third parties, refer to the NHVR website - Approved Guidelines for Granting Access.
A field trial is not:
- a measurement of all vehicle performance criteria
- a measurement of tracking ability on a straight stretch of road
- a measurement or assessment of road safety.
Field trials are used to assess a vehicle's compatibility with the road environment, in particular:
Swept path performance
The swept path of a vehicle must track inside the path taken by the steering axle in a low-speed turn, plus vehicle width. In some scenarios, the actual swept path achieved by drivers in on-road scenarios may be better than predicted by computer-generated models, such as AutoTURN. These models utilise standardised Austroads vehicle templates that broadly represent classes of similar vehicle combinations but may not be indicative of the absolute worst case.
Stopping sight distance
The driver of a vehicle approaching any intersection on a priority road must have sufficient visibility to observe another vehicle at or within the intersection and stop if necessary.
Stacking at intersections
There should be sufficient road length (stacking distance) between any intersecting roads or crossover locations - eg railway level crossings, slip lanes and intersections.
Requirements
Prior to commencing a field trial, the following requirements must be met:
- an appropriate area or facility must be established where all parties can meet
- the vehicle’s axle spacings and overall length will be measured to determine compliance mass and dimension limits stipulated in the Queensland Government Heavy Vehicle (Mass, Dimension and Loading) National Regulation (2021)
- trial signage must be displayed on the vehicle
- the operator must acknowledge that they are liable and responsible if the field trial results in a traffic incident and or if there is damage to road infrastructure or property.
Requesting a field trial
The applicant can request a field trial by submitting an access permit application through the National Heavy Vehicle Regulator Portal. The permit application must state that it’s for ‘trial’ purposes and include any supporting information such as:
- any access refusal decisions that stated a trial may be considered
- previous access application case numbers
- details of correspondence with Road Managers.
For more information on the field trial process, refer to the NHVR website - Approved Guidelines for Granting Access.
Decision making
Based on the field trial outcomes, the Road Manager will either:
- provide access consent, which may include access conditions
- refuse access, which will be justified with reasons based on the field trial, for example:
- the vehicle could not safely negotiate the intersections
- sight distance was significantly deficient imposing a safety hazard.
If the trial applicant is not satisfied with the decision of the Road Manager then they can seek a review by emailing the Director, Network Management Services at dit.inquiriesadministrator@sa.gov.au.
For a summary of the field trial application process, refer to the Field Trials Flowchart (297.9 KB PNG).
