#68 Local Street Management (pt 5) - Scheme design

The fifth entry in the current series on Local Area Traffic Management (LATM), as informed by the AGTM Part 8: Local Street Management [1], outlines Stage 4 of the LATM process, covering Scheme design. This stage proceeds following approval of the draft scheme that was selected and presented to council as the final task in Stage 3.

Stage 4 Tasks

Scheme design essentially involves the preparation of detailed plans, costings, timelines and tasks for implementation. According to Austroads, the detailed design and documentation should inform and capture a range of tasks, including:

• Further street surveys and audits (if required)

• Preparation of detailed drawings on design of devices

• Landscaping plans and specifications

• Preparation of construction and contract documents

• Ongoing communication and consultation with residents and other stakeholders

• Development of a maintenance strategy

• Funding considerations, including pursuit of external funding where available.

Design of devices

Detailed design is informed by a range of key reference documents, some of which have national application while others are jurisdiction-specific. National documents include guides from Austroads and the National Transport Commission, and Australian Standards, including relevant parts of the Manual of uniform traffic control devices. State and Territory transport departments then provide various manuals, guides and related documents specific to their jurisdiction.

Austroads identifies two stages to be covered in detailed design, including (p.46):

• Layout design, to determine the form of the device

• Engineering design, as part of construction documentation.

  
  

A difference is noted between standard traffic design and LATM, where the former aims to ‘facilitate the safe and efficient passage of vehicles’, while LATM typically ‘seeks to impede vehicles' (p.46):

Doing this without adding to the level of risk is the heart of LATM design (Section 7). A detailed design stage road safety audit is an intrinsic part of this stage.

Another challenge comes from the fact that LATM devices (particularly horizontal deflection devices) induce slower speeds by employing tight geometry – yet adequate design for larger vehicles requires greater clearances and swept paths. Appropriate design templates should be adopted, but use should be made of mountable kerbs and run-over areas to help define a tighter path for general traffic.

[1] Austroads (2020). Guide to Traffic Management Part 8: Local Street Management. Sydney, Austroads. https://austroads.gov.au/publications/traffic-management/agtm08