Road classification in New Zealand

New Zealand is one of the smallest countries by population, with 4.4 million inhabitants (122nd). The country has a total network of 83,000 km of local roads and 11,000 km of state highways (link). The local roads are managed by 68 road controlling authorities (RCAs) which largely appear to be the same as the country’s 11 regional councils and 67 territorial authorities. Howevre the RCAs online forum at (link) says there are 73 territorial local authorities. Responsibility for the state highways now rests with the New Zealand Transport Agency (NZTA) which was set up in 2008, following some years of changes in the responsible government agencies.

Another, surprising participant in the management of NZ’s road network is the national standards agency, “Standards New Zealand“. Ist important 2010 publication NZS 4404 : 2010 is of international interest in the debate on land use planning, road classification and road networks.

History of road classification in New Zealand

New Zealand has been thinking over its road classification and road hierarchy for some years now. Even now the country does not have a single road hierarchy or road classification, and there does not seem to be any clear agreement on how to define road hierarchy and road classification.

 Local roads

In 2001 a survey was carried out by the then  Land Transport Safety New Zealand (LTSA) a government body which was absorbed into what is now the NZ Transport Agency. The survey (ref. 251) concerned the country’s 67 road controlling authorities and their road hierarchies.  All the RCAs said they “had a road hierarchy in one form or another”. The survey results indicated that there were 29 distinct urban road hiararchies and 29 distinct rural road hierarchies, and that “most authorities reported they ranked roading works by giving priority to the most important streets or roads in their roading hierarchy.” The report argued that  “New Zealand needs an agreed functional road hierarchy for the entire road network” (own emphasis).

 In 2010 the agency “Standards New Zealand” published a document NZS 4404 : 2010 Land development and subdivision infrastructure (referred to above). According to a paper by Keith Hall (ref. 252) it is not a mandatory standard. The paper says there is a change in this version compared with the old NZS 4404 : 2004, with the emphasis of road design no longer on moving vehicles. Mr. Hall also says that in the new standard road hierarchy is described as link context. The new standard also relates roads to land use and function and then to target operating speed, classification, traffic volume, lane width, cycling elements etc. It emphasises the ideas of ‘connectivity’ and ‘networks’. The new document has its own system of road classification which Neil Johnstone describes in (ref. 253).

State roads

A 2007 paper by Andrew Macbeth (ref. 250) recommended the establishment of a national road hierarchy, saying that “There  are  over  100  different  road  hierarchies  in New Zealand” and that “a  number  of  existing  hierarchies distinguish between state highways and other arterials, but it is felt that this difference is not necessary (or helpful”.  Mr.  Macbeth also argues that “adding road classes just to cover ownership is counter-productive to the principle of self-explaining roads”.

The NZTA invited comments on a draft for a state highway classification system around 2010. Amongst those responding, IPENZ and Roading New Zealand said in 2011 (ref. 254) that “The  state  highway  classification  system  needs  to  be  seen  as  part  of  a  national roading classification system.”

In 2011 NZTA published a consultation draft “State Highway Classification” (ref. 267). It relates classes (categories) of road to function, function to level of service and level of service to design. The document suggests seven criteria for classification. These include traffic flow (annual average daily traffic).  The suggested classification has four classes (categories) and relates each of these to the seven criteria.

Current road classification in New Zealand

For urban and rural roads NZS 4404 : 2010 appears to propose

  • lanes
  • local roads
  • connector / collector road

 For state roads the draft “State Highway Classification” has four classes

  • National strategic (with a high volume subset)
  • Regional strategic
  • Regional connector
  • Regional distributor

However the NZTA website dated August 2012 still says that “We use the following road hierarchy to help plan the state highway network:”

  1. motorways
  2. expressways
  3. primary arterials
  4. secondary arterials

Opinion

Much good work has been done (and is being done) in New Zealand on road classification. However there still seem to be weaknesses in the national debate on the topic. NZS 4404 : 2010 seems to be well worth reading for its very detailed work relating connected networks, land use, highway geometrics and road classification.

1. Terminology

In New Zealand’s debate on road hierarchy and classification the use of these technical terms is unclear and inconsistent. For example the 2011 draft State Highway Classification refers both to classification (i.e. classes) and to categories. In fact it can be argued that road hierarchy(s) are functional road classifications, and are sub-sets of a broader road classification system. Such a system could have classes defined by measures such as

  • traffic flows
  • ownership
  • speed limit (in fact speed limit or design speed is probably the determining factor in highway geometrics)
  • hierarchy based on long-distance car trips

2. Completeness

The separation between state roads and other roads is administrative. All these roads should actually form part of an integrated network. The NZS 4404 : 2010 emphasis on connectivity and networking could also be applied to New Zealand’s state roads as well as to its urban and rural roads. IPENZ and Roading’s submission on the state highway classification (ref. 254) asks “why the NZ Transport Agency is developing a classification system that does not cover local roads” and says “we note there does not seem to be any alignment (with) the roading classifications in NZS 4404:2010”.

3. Scaleability

As you zoom into a road network, looking at it in more detail, the same concepts should apply (functional classification, networking, connectivity) as at the larger scales.

4. Comprehensive

Everyone involved in the debate in New Zealand would probably agree that work does not stop once a road classification system has been agreed on; the classification should be developed to relate to “aspects” such as highway geometrics, design speed, traffic volume, road cross-section, cycling facilities and so on. Indeed both NZS 4404:2010 and the draft state highway classification both try to do this, although to different extents and levels of detail.

5. International applications

Andrew Macbeth’s 2007 paper argued for a national road hierarchy. His arguments could also be applied in favour of a single, international road classification system. This would help clear away the fog of terminology which makes it difficult to compare road solutions from different countries. Further, the NZS document’s idea of measures of urban and rural connectivity could be applied to other countries as well, although the values applied would likely vary. What is a reasonable value for rural connectivity in NZ may not be achievable in Tanzania or Nepal.

References

250 “A national road hierarchy – are we ready?”, Andrew Macbeth, IPENT Transportation Conference 2007

251 “RSS 16 Road Hierarchies”, Land Transport Safety Authority, 2001

252 A paper on the NZS 4404 : 2010 by Keith Hall, publication available on the Internet although year and source of publication not clear

253 “NZS 4404 – a roading perspective”, a paper on the 2010 edition by Neil Johnstone for the NZ Road Controlling Authorities Forum

254 IPENZ and Roading New Zealand, submission to the NZ Transport Agency on the state highway classification, March 2011

267 “State Highway Classification, Consultation Draft”, published by the NZ Transport Agency, February 2011.

Advertisements

About roadnotes

Robert Bartlett is an international consultant with over 30 years of professional experience as a highway and traffic engineer with leading companies and organisations in several countries, including Germany, China (Hong Kong), Qatar and the UK. Specialised in urban studies, transport and the use of GIS, research has included new ideas on subjects such as the study of social justice using GIS, the dimensions of vehicles, and comparative geometrics (highways and transport).
This entry was posted in classification. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s