Vehicles travelling on our roads must be within a certain size and weight so they can fit on the road safely, don't impede other traffic and don't damage roads and bridges.
The maximum size and weight dimensions for vehicles are set out in the latest Land Transport Rule: Vehicle Dimensions and Mass (VDAM), but sometimes larger or heavier vehicles need to use the road. If your vehicle exceeds the usual size and weight dimensions, you are likely to need to get a permit.
Applications for overweight or over-dimension permits on ADC roads are made through the NZTA website, which also provides more detail to help determine if you need a permit : https://www.nzta.govt.nz/commercial-driving/
High Productivity Motor Vehicle (HPMV) and 50MAX permits include specific routes, and these are approved by the relevant RCA. ADC has pre-approved some routes for HPMVs (which includes 50MAX by default), to assist during permit assessment. Routes applied for but not on the pre-approved list will be assessed individually. The latest pre-approved list can be found here.
A key constraint for heavy vehicle movements are bridges. There are a number of bridges that have heavy vehicle limitations and these should be noted when planning routes. The latest list (as at 18 December 2020) is here.
An interactive map is available showing pre-approved HPMV routes, bridge information, cattle stops, gravel fords, river sections and gates (as at 18 December 2020): http://ashburtondc.govt.nz/hpmv-route-map/.
A GoogleEarth map with the same information is also available for download here. Google Earth will need to be used to view this file.
During emergency events you may need to divert or delay travel. The controlling authority at the time of the event (which could be Civil Defence or Police, rather than ADC) is able to restrict travel if required, and existing permits could be revoked or amended. In some cases, new permits may be required for alternative routes.