Effective from 1 July 2006, Austroads has replaced the former National Association of Australian State Road Authorities (NAASRA) 'administrative tolerance' used for heavy vehicle mass enforcement with a Measurement Adjustment that is based solely on weighing equipment accuracy and site characteristics.

Enforcement action may be taken when a vehicle's assessed mass exceeds the legal limit. The assessed mass is calculated by subtracting the measurement adjustment from the vehicle's mass as shown on the measurement equipment. There are three categories of measurement adjustment that are designed to take into account the variations in measuring equipment and site characteristics.

Enforcement officers determine, which category of weighing applies to a given situation and apply the appropriate measurement adjustment to calculate the assessed mass.

The attached information bulletin explains how Measurement Adjustment [pdf, 195 kb, 2 pp]  in relation to Heavy Vehicle Enforcement weighing works.