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The National Traffic Database (NTDB) is a system for storing traffic data on each of approximately 120,000 sections of New Zealand public road network (state highways and local roads). It incorporates data collected by each Road Controlling Authority (RCA), ie by Transit New Zealand Regional Offices for state highways and by each Territorial Authority (TA) for local roads. The road sections are as defined in the RAMM (Road Assessment and Maintenance Management system) databases of each RCA.

It describes the relative traffic demand on New Zealand public roads, in terms of traffic volume (ie annual average daily traffic or AADT), traffic composition by vehicle class and by vehicle weight. Such a compilation of these data does not appear to have been made elsewhere in the world.

The availability of the National Traffic Database will provide:

• accurate information on vehicular travel
• comparative information for traffic demand both in terms of volume and of ESALs (equivalent standard axles) between RCAs or between road use categories on an aggregated national basis.

To improve the accuracy and usefulness of the NTDB, the additional classification surveys that have already been designed need to be completed. In the longer term, an ongoing programme of vehicle classification surveys and vehicle weight surveys needs to be implemented.

At present, estimates by vehicle class at a national level have a precision of approximately ± 10%, whereas at a TA level, estimates by vehicle class have a precision of the order of ± 30% to 40%. Estimates involving weight estimates are relatively less precise.

The project, begun in 1994, is reported in three parts:

Keywords: Database, national, National Traffic Database, New Zealand, quality plan, planning roads, road use, traffic, traffic flow, traffic volume, vehicles, vehicle class, vehicle weight, weight