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Measurement Adjustments


The enforcement of the heavy vehicle mass and dimension laws rely on measurements taken by inspectors. These measurements need to be accurate enough to satisfy a Court “beyond reasonable doubt.”

Given the scope for human error and the fact that these measurements are often taken in less than ideal conditions, how can truck drivers be sure that they can believe the weights and dimensions recorded by inspectors? Further, how can the authorities be sure that their measurements are accurate enough to rely on in Court?

The authorities use two processes to overcome these problems.

The first safeguard is that all measuring implements (such as tape measures, weighbridges, portable axle weighers etc) are tested and certified for accuracy. This reduces the chances of manufacturing faults or wear and tear causing inaccurate measurements.

In Court proceedings the prosecutor will usually produce evidence that the measuring devices have been tested and proven accurate. This means that in most cases, a person who is defending a mass or dimension offence will have difficulty arguing that the measuring device was inaccurate unless they have specific evidence to prove that.

Even if the measuring tools are accurate there is always scope for human error. Accuracy can also be affected by the conditions that a measurement is taken in, for example a weigh bridge is more accurate than portable axle weighers. A height measurement will be easier to take on a flat surface than on an incline.

To counter these problems and ensure measurements can be relied on in court, the enforcement authorities use a system of ‘measurement adjustments’. It simplest terms, they reduce the weight or measurement by a certain amount to counter any potential inaccuracy. This is the second safeguard.

The actual system used to calculate the measurement adjustments is quite complex. The amount deducted depends on factors such as the:

  • type of measurement being taken, i.e. gross mass, axle mass, height, length or width.
  • inspection site, e.g. a weighbridge vs portable axle weigher, whether the site is flat, whether the surface is bitumen or not.
  • characteristics of the vehicle, e.g. it’s permitted operating length, how many axles does it have?

It is important that people do not try to use these measurement adjustments as a leeway. Some truck operators have been known to try to carry a slightly over limit load, relying on the fact that a small deduction will be made from any measurement. However, this is very risky. It is impossible to know in advance exactly what measurement adjustment will be applied.

If you believe that an inspector has incorrectly measured or weighed your vehicle, there are a few steps that you can take to help defend yourself:

  • As soon as the Inspector is finished with you, take photographs of the location that the inspection took place. This can help you prove that the inspection site contributed to an incorrect measurement.
  • Measure or weigh the vehicle yourself as soon as possible, preferably in the same location if possible, safe and legal to do so. Take photographs of this process.
  • Collect and keep any evidence that you can about the dimension or mass of the vehicle, for example container weight declarations or weighbridge receipts.

Image Credit – Gennady Kireev © 123RF.com

Written by Sarah Marinovic on March 11, 2018

Sarah has a strong drive to use her legal knowledge to help people in times of difficulty. Her goal is to not only achieve the best legal result, but to also ensure that her clients understand each step, and what is required from them to achieve the best results. With her friendly manner she strives to ensure that he client's mind is at ease throughout the process. View Sarah's profile


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