Test drilling has commenced in Kedron as part of early investigations into a bypass tunnel currently under assessment as a potential solution to ease traffic congestion on Gympie Road.
Background and Context
Test drilling activities are underway along the proposed alignment of the North West Transport Corridor, targeting a section between Kedron and Carseldine. The tunnel, estimated to exceed $14 billion in cost, forms part of broader efforts to reduce pressure on one of Brisbane’s most congested roads—Gympie Road.
Originally reserved as a future corridor in the 1980s, the 9km stretch from Carseldine to Alderley has since become an urban green space and wildlife habitat. The corridor has remained undeveloped for decades while urban traffic volumes steadily increased across Brisbane’s north.
Project Scope and Technical Planning
The early works involve drilling rigs and utility trucks deployed along the investigation area to gather information on soil and groundwater conditions. These tests are intended to inform the most effective construction methods for a future tunnel.
Oversight of the project transitioned to the Department of Transport and Main Roads (TMR) from North Brisbane Infrastructure as of 1 July 2025. TMR is now responsible for conducting detailed transport modelling, technical analysis, and exploring provisions for public and active transport, including bike lanes.
Previous allocations of approximately $300 million have been committed to preliminary works, with an additional $35 million set aside in the prior year for assessing tunnel viability.
Tunnel Options and Alternatives
Two tunnel options have been presented as potential solutions to bypass Gympie Road. The first involves an 11.75km tolled tunnel connecting Airport Link at Kedron to Gympie Arterial Road at Carseldine. The second, shorter proposal follows an 8.5km route largely beneath Gympie Road.
Tunnel-only costs were estimated at $9.2 billion for the longer route and $7.9 billion for the shorter version. Infrastructure Australia previously rejected both proposals due to a lack of detailed assessment for lower-cost surface road alternatives.
Community and Network Considerations
While the corridor remains technically available, its present function as green space presents a barrier to surface-level developments such as rail links or above-ground roads.
A spokesperson from Transport and Main Roads indicated that realising the benefits of a tunnel solution depends on effective integration with the broader northside transport network. The transition of project oversight to TMR is intended to align the proposal with broader infrastructure strategies.
Next Steps
The current round of test drilling in Kedron is expected to conclude by the end of the month. The findings will support future decision-making regarding tunnel design, alignment, and feasibility. Further updates from TMR are anticipated as planning work progresses.
Updated 14-August-2025. Published 14-July-2025
