This is the first of a series of articles on ACT building codes. The character and liveability of our city is a product of these codes. Here is a brief introduction to Estate Development Code and why it needs to be revised.
Planning code hierarchy
The Estate Development Code is part of hierarchy of documents.
Under the Planning and Development Act 2007, where more than one type of code applies to a development and there is inconsistency between provisions, the order of precedence is: precinct code, development code, and general code.Estate Development Code, ACT Government, effective 4 October 2013, page 2
For greenfield estates it appears more likely there will be a concept plan than a precinct codes, but a concept plan serves the same purpose for this discussion. The Holt Precinct Code for Kippax, Belconnen, has been attached for those interested and wanting to study an example of a precinct code.
Concept plans are produced as part of the planning process for any new estate and included in the Territory Plan. A typical hierarchy is therefore:
- Coombs and Wright Concept Plan, 20 June 2014
- Estate Development Code, 4 October 2013
- Crime Prevention through Environmental Design General Code, 16 December 2011
Estate development plans
A new suburb is maybe too large to build in step and therefore broken into stages. In this way, a supply of blocks is released onto the market each year. Whitlam was broken up into four stages. Before the construction begins, the plans need approval through an estate development application. The process can also apply in older areas, a recent example being a medium density housing complex in Dickson.
Estate development plans (EDPs) set out the proposed subdivision pattern and infrastructure works for an estate. EDPs must be submitted as development applications for approval by ACTPLA.Estate Development Code, ACT Government, effective 4 October 2013, page 2
Development approval of the EDP is required before design acceptance can be obtained from TAMS, works can commence and leases issued for the subdivided blocks. The EDP is assessed against the relevant parts of this code and any applicable structure plan or precinct code.
The Estate Development Code uses a slightly different street hierarchy to the Active Travel Key Documents.
Key documents – Standards and guideline documents which should be used in the planning and design of active travel facilities. These are listed in Sections 2.2.3 to 2.2.7.Active Travel Facilities Design – Municipal Infrastructure Standards 05 (MIS05) (ACT Government, April 2019)
The Estate Development Code does not address arterials and highways. In the Active Travel Infrastructure Practitioner Tool (ATIPT), the estate hierarchy is reduced to Major Collector, Minor Collector and Local Access Street.
Major collectors are common in the older suburbs, such as those found in Belconnen, but not in the new estates of the Molonglo Valley or Ginninderry (West Belconnen). Historically, they were important but that is not the case now.
Major Collector Roads collect and distribute traffic within residential, industrial and commercial areas. They form the link between the primary network and the roads within local areas and should carry only traffic originating or terminating in the area.Table 1A: Street hierarchy for estates in residential zones and CZ5. Estate Development Code, ACT Government, effective 4 October 2013, page 27
Major collectors have a design speed limit of 70 km/h and traffic volume of 3001-6000 vehicles per day. It is not something you would want at your front door. These are busy roads.
It seems that major collectors do not fit into the modern urban landscape. With a little clever design they can be avoided and much space saved. In Whitlam Stage 3 the major collector is extremely short, reaching from John Gorton Drive to the local shops. According to ATIPT, Coombs and Wright do not have any major collectors. The recent Macnamara Estate Development Plan (EDP) also does not feature any major collectors.
Active Travel Infrastructure Practitioner Tool (ATIPT) – A web-based user interface that provides access to spatial mapping of the Active Travel Routes for walking, cycling and equestrian routes (ATRA) as well as access to planning and design policies, guides and other information relevant to the planning and design of active travel infrastructure in the ACT. The tool is available for use by all stakeholders including government agencies, developers and consultants and may be accessed at http://activeinfrastructure.net.au/Active Travel Facilities Design – Municipal Infrastructure Standards 05 (MIS05) (ACT Government, April 2019)
Minor collectors are found in suburbs of any size and in new suburb designs increasingly as a substitute for major collectors. The big difference to major collectors is that minor collectors have lower speeds and are much more likely to have property access.
A minor collector road collects and distributes traffic from access streets to major collector roads or direct to the external arterial road network. A reasonable level of residential amenity and safety is maintained by restricting vehicle speeds by means of street alignment, intersection design or by speed-control measures. Direct property access is allowed.Table 1A: Street hierarchy for estates in residential zones and CZ5. Estate Development Code, ACT Government, effective 4 October 2013, page 27
Minor collectors have a design speed limit of 60 km/h and traffic volume of 1001-3000 vehicles per day. You may live on one, but it is certainly not a quiet street. They are wide, hard to cross, particularly for children, and 60 km/h is too fast for a vulnerable road user – including the elderly and vision impaired – to feel safe negotiating. Minor collectors may have local bus routes and bus stops. Older suburb designs have local shops or a primary school in the centre of the suburb on a minor or major collector.
Local Access Street
What is labelled in the Active Travel Infrastructure Practitioner Tool as a Local Access Street is found in the Estate Development Code as one of two types: Access Street A and Access Street B. Table 1A: Street hierarchy for estates in residential zones and CZ5 from the Estate Development Code, and would suggest they differ in traffic volume and design requirements. The expected traffic volume determines the type of street and consequently the design requirements. Access street A has a traffic volume of 0-300 vehicles per day, and access street B 301-1000 vehicles per day.
Access streets are used where the residential environment is dominant, traffic is subservient, speed and traffic volumes are low and pedestrian and cycle movements are facilitated. Access streets are categorised as Access Street A or Access Street B according to traffic volumes. Access Street A generally collects traffic from rear lanes and connects to collector roads; they do not normally accommodate traffic from other streets.Table 1A: Street hierarchy for estates in residential zones and CZ5. Estate Development Code, ACT Government, effective 4 October 2013, page 27
“Rear lanes” as a street type were never common in Canberra. The new suburbs have rear lanes that are gaining popularity to provide access between two rows of town houses with a 20 km/h speed limit. In practice, they look like a pedestrian area, but residents will drive their car through it. There will be a handful of visitor parking spots. Rear lanes are common in the Ginninderry suburb designs.
The criticism of RobertsDay
We see in the Estate Development Code, that the type of street required is the result of travel volume predictions. The traffic volumes are derived from values found in the Estate Development Code.
The quote is for street network requirements for all estates, except in industrial zones, but applies too for the street hierarchy for estates in residential zones and CZ5. In short, it applies to all new estates.
For residential and CZ5 zones – to calculate the traffic volume for streets apply a traffic generation rate of:Table 2A: Street network requirements – all estates except in industrial zones, Estate Development Code, ACT Government, effective 4 October 2013, page 43
– 8 vehicle movements per day for single dwelling blocks larger than 360m2
– 7 vehicles per day for single dwelling blocks 360m2 or smaller
– 6 vehicles per day per dwelling for multi unit developments.
The report for RobertsDay is critical that the streets in new estates are over provisioned as a result of outdated assumptions of traffic volumes. The report argues that these assumptions are inconsistent with the active travel goals.
The introduction of active travel in the Territory Plan in 2017 has changed the nature of the discussion about urban planning. The design brief of Molonglo 3 East requires designs to encourage active travel and reduce car dependence. The expectation is that increasingly people will walk or ride rather than drive the car, presuming they even have one. In European cities this scenario is already very common.
Molonglo 3 East will be a mix of low, medium and high density housing. The ACT Government prescribes the total number of dwellings to be built in the estate (yield). With the acceptance of greater urban density the numbers have become quite large. Increasing housing density ratchets up the traffic predictions and, as a consequence, higher capacity and larger road types are required that take up much more space.
It may seem counterproductive that packing more people in per square km results in a great portion of that area being allocated to roads. The naive expectation is that more people in the same area can be achieved without more roads. While this is true in older suburbs (infill and renewal) it is not possible under the Estate Development Code for new estates.
This is the point made in the Molonglo 3 Stage 2 Proof of Concept report by RobertsDay. The Estate Development Code is archaic and at odds with the future focused ACT strategy for great urban density, which was first outlined in the 2004 Canberra Spatial Plan. 17 years later, the Estate Development Code has not caught up. The reference to TAMS and no reference to the Active Travel Standard documents (PATACT, MIS05, ACTSD, ATRA from ATIPT and Austroads AGRD06A) would indicate that it needs to be revised.
At some point, something has got to give. We cannot increase the yield of Molonglo 3 without at the same time decreasing the proportion of space allocated to road reserves. This is not possible under the current traffic assumptions found in the Estate Development Code!
The next article will be on the General Code: Crime Prevention through Environmental Design General Code, 16 December 2011.