Factsheet 53 – August 2009

Work out the category

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The requirements for overdimension vehicles depend on their width, length, forward distance, front overhang and rear overhang. Vehicles over 4.25 metres high are also overdimension, and need to meet certain requirements.

The graph below shows which category your vehicle and load fall into, based on the width and the forward distance. (Read the factsheet 13 series if you don't know how to calculate forward distance.)

Graph: Determining category, based on width and forward distance

Find the horizontal line on the graph that matches your vehicle's width, and the vertical line that matches your vehicle's forward distance. Where these two lines meet determines your category. (Work out the category for each vehicle in a combination, and follow the requirements for the highest category vehicle.)

Width and forward distance are only two of the five dimensions that determine whether your vehicle or load is overdimension. Your vehicle or load will also fall into Category 1 if:

• the length is over the maximum allowed for a standard vehicle (including combination vehicles), but not more than 25 metres, or
• the front overhang is more than the maximum allowed for a standard vehicle, but not more than 7 metres, or
• the rear overhang is more than the maximum allowed for a standard vehicle, but not more than 7 metres.

Read the factsheet 13 series if you don't know the maximums allowed for standard vehicles.

Your vehicle or load will fall into Category 2 if:

• the length is more than 25 metres but not more than 35 metres, or
• the front overhang is more than 7 metres but not more than 10 metres, or
• the rear overhang is more than 7 metres but not more than 10 metres.

Any dimension falling into Category 1 (and none in Category 2) puts your vehicle in Category 1. Any dimension falling into Category 2 (and none in Category 3) puts your vehicle in Category 2.

If the vehicle or load is more than 35 metres long, or has a front overhang or rear overhang of more than 10 metres, you are in Category 3 or 4 and need to contact OPIA.

Combinations falling on the upper boundary of Category 1 on the graph are treated as Category 1 loads, and those falling on the upper boundary of Category 2 on the graph are treated as Category 2 loads.