Highforest by Mirvac is a family-friendly residential community built on the site of the former IBM headquarters in West Pennant Hills. Across a 25.87-hectare property, approximately 10 hectares are protected as environmental conservation. The development delivers 417 dwellings across houses and apartments, divided into four residential precincts alongside a recreation facility and open space.
Achieving a 6 Star Green Star Community rating, Highforest is defined by its sustainability credentials and its connection to the surrounding natural environment.
The challenge
A project of this scale requires more than the design elements typical of residential developments. In addition to car parking, bicycle facilities, and pedestrian infrastructure, the internal road network had to be designed to serve all four precincts.
The design team’s interpretation of Council planning controls required waste vehicles (heavy rigid vehicles) to be able to pass each other across all parts of the internal road network. Applied literally, this requirement produced road widths of up to 20 metres on some bends.
For a residential community, this was a significant problem. Oversized roads reduce the space available for footpaths and green areas, limit placemaking opportunities, and can encourage vehicle speeds that make the environment less safe for pedestrians. Given that these roads would be used by heavy vehicles only a fraction of the time, the client needed a solution that preserved the character of the community without compromising compliance.
“We approach these situations by focusing on the end user and how the space will be utilised once built. Ultimately, what we aim to achieve is a design that is compliant, works in real life, and brings maximum benefits for the community while achieving our client’s goals.”
Andrew Morse, Managing Director, ptc.
The solution
ptc. was engaged following the submission of the Masterplan Development Application. Our traffic experts undertook a careful review of the Council requirement and the interpretation being applied to the road design.
Our assessment identified that the critical issue was not road width itself, but sight lines. On straight sections, drivers can see approaching waste vehicles well in advance and stop to allow them to pass. The risk was confined to bends. Provided sight lines on bends were protected, there was no engineering basis for widening roads to accommodate simultaneous vehicle movement.
Our engineers reviewed the plans to confirm that adequate sight lines were maintained at all bends. Once we determined this solution was feasible, we worked with the design team to adjust the concept road designs. Road widths on bends were reduced from 20 metres to 10 metres.
The revised design was then taken to Council for approval in principle. The project has since progressed through multiple Development Applications and is currently under construction. ptc. has provided traffic engineering services across all DAs and is continuing to support the project at the current stage.
Client: Mirvac
Location: West Pennant Hills, NSW
Services:
- Concept and detailed design
- Transport Impact Assessment
- Construction Traffic Management Plan
- Construction Certificate
Image credit: Mirvac