The National Road Centreline – supporting planning and decision-making on New Zealand’s roads

Bringing together local knowledge with central resources

At the Transport Agency, our purpose is to create great journeys to keep New Zealand moving. Making the right investment decisions in the transport system and how this system is efficient and sustainable, relies on having a reliable, accurate, up-to-date and actively managed spatial centreline dataset.

A road centreline dataset is as it sounds: a dataset of spatial data, giving an accurate reflection of the real-world centreline of the actual road. A consistent centreline dataset provides the ‘spine’ or reference that all manner of spatial roading data can be aligned with or attached to. Lacking a consistent centreline means that data cannot be easily compared or collated, routes are poorly planned, and automation of spatial analysis and planning is made more challenging.

Local government, or councils, manage their centreline datasets in a Road Asset Management System (RAMM) that does not allow the sharing of data on local roads, such as vehicle counts and surface type. Additionally, councils, especially small or fast-growing councils, do not always have the capability or capacity to ensure their centreline datasets are up-to-date or accurate.

All of this meant there were 68 different road centreline datasets of varying quality and accuracy across all of New Zealand. The Transport Agency, working with the Road Efficiency Group, recognised the difficulties this presented, and the opportunity to do better – the Road Centreline Project was born.

Joining public data with private IP

The project saw the Transport Agency procure a centreline dataset that would support local councils. It had to be able to incorporate all 68 road controlling authorities’ (RCAs) centreline data, and merge this with an accurate managed and maintained centreline dataset. The result would be a new hybrid, publicly/privately owned dataset.

As well as being the driving force for this project, the Transport Agency had a key role in bringing together private providers of data, software and services, with local council teams responsible for the roads in their regions.

The private provider of the centreline itself was CoreLogic, who hold the IP for the centreline, and who update it regularly. Alongside RSL (the creators of the councils RAMM software), the Transport Agency and CoreLogic were able to ensure the centreline could be merged with local council information (such as usage or surface type) about the roads.

It was important to the success of the project that this was very much about working with the councils. To do this the Transport Agency needed to support local councils (road controlling authorities) providing data and tools to easily manage and maintain their centreline datasets. The team were then able to share this centreline (their data attached to the managed centreline) back with local councils through a tool that would enable them to easily incorporate the managed and maintained centreline into their own RAMM data.

The result: Councils and the Transport Agency have access to a trusted, authoritative view of the real-world road centreline, in one accurate and accessible dataset. To date 16,682 sections of the road centreline across New Zealand have been accepted into councils’ own data. Of the top 10 RCAs using the centreline, eight are district councils and two are city councils. Collectively, these 10 RCAs have accepted over 70% of their centreline changes. The National Road Centreline Project didn’t stop there.

Open data on the open road

The team recognised early on there was value in sharing the new centreline dataset. Opening up a dataset held in a public-private/central-local partnership was not without its challenges. Private companies expect their intellectual property to be protected. Councils, however, expect to be able to share data for the benefit of their communities, this meant a compromise had to be sought. As this project navigated a range of legal concerns, it required a lot of negotiation to achieve a great outcome for all.

Every council was walked through the data sharing process. Through frequent contact, working with legal teams, and the councils, compromises and solutions were found for almost every situation. One council, for example, has opted not to use the centreline within RAMM but wants to include their data in the centreline for other councils and the public to view. We have been open to this option and are working through it with them.

The result has been that 52 (78%) of the 68 RCAs have so far signed the Data Sharing Agreement that gives them access to the CoreLogic Centreline datasets and opens that data to the public. That’s over two-thirds of New Zealand having access to, and using, a managed and maintained centreline dataset in their day-to-day management and maintenance of our roads; directly benefiting our road users and keeping New Zealand moving.

Heading into the future

We are excited at the prospect of having all 68 RCAs signed up to the (or an) agreement that will allow us to share the managed centreline data with them, and their data with other councils and the public. We’ve learned much about councils and the way they work and will use these lessons and relationships to ensure our future projects have an equally positive outcome. There are multiple possibilities that the open centreline dataset might bring in the future.

While the centreline is not able to be on-sold, it can be used by anyone. It might be used by a trucking company to better plan routes for its nationwide fleet this week; and next week it might be used by roading contractors to predict where their assets will be needed in the year ahead; residents might draw on it to understand the traffic in their neighbourhoods; or the council might use it to understand how road assets are being managed at the other end of the country. That is the beauty of opening up the centreline dataset – it opens up more possibilities for keeping New Zealand moving.

The centreline dataset is available to the public via NZ Transport Agency’s Open Data Portal, ensuring anyone can view the centreline and local council data in one place.

Author Louisa Bloomer, NZTA

Louisa Bloomer project managed the delivery of the National Road Centreline Project for the Transport Agency to bring everyone along on the data sharing agreement journey. Louisa currently manages the Statistical Analysis team within the Transport Agency.