Vehicle Weight Restrictions

Many people forget when they get behind the wheel of a particular vehicle to drive it that their licence may not necessarily cover them legally to drive it. In this instance many have found themselves to be breaking the law – for the most part unintentionally – but breaking the law nonetheless.

With this factor in mind it is worth looking at the recognised vehicle weight restrictions and how they apply to the driving licences held by many of us driving on the roads today.

MAM – Maximum Authorised Mass

The Maximum Authorised Mass (MAM) is the weight that a driver of a specific vehicle is legally allowed to carry. This weight equates to the contents of the vehicle and does not include the weight of the vehicle itself. For example a vehicle may weigh 1500kg and its Maximum Authorised Mass may be 1000kg.

This weight is normally shown on the vehicle on a plate which is used to indicate to all drivers of the vehicle just how much weight in addition the vehicle’s actual weight they can transport.

Plated Weight

As we have already indicated all vehicles should be fitted with a metallic plate which will give the driver the approximate weight he or she can carry safely over and beyond the actual weight of the vehicle they are driving. This plate is fitted at the time of manufacturing and it is a criminal offence for this plate to be removed or – if the plate is missing or has fallen loose – not to be replaced. This plate must be shown so that all drivers of the vehicle are aware of it’s maximum load bearing potential.

Train Weight

Just as a train would pull wagons or carriages so too do trucks and articulated Lorries. Indeed any vehicle that is capable of pulling a trailer or so-called box along behind it must display a train weight. This weight is the combined total of the Maximum Authorised Mass (MAM) and the weight of the trailer. It is important to take into consideration any additional trailer weight when driving a vehicle as this weight can have an adverse affect on how the vehicle is handled.

Unladen Weight

The unladen weight of a vehicle is the weight of the vehicle itself. Normally this weight is displayed on any plates attached to it and it is weight of the vehicle including all moving parts which are responsible for propelling the vehicle such as the engine, gears and hydraulics. Water, oil, petrol diesel are not included in this unladen weight calculation as they are required to supply power to the vehicle in order for the working parts to make it move. In addition to this these liquids can alter in weight as they are used during the course of any journey.

It is important to have an understanding of the weights of any vehicle you may have to drive throughout your driving life and it is also important to have a grasp on what effects misuse or overloading can cause. Too much weight in a vehicle can cause damage to suspension, wheels and indeed the gear mechanisms and also can slow the vehicle down which can increase the risk of accidents.

For more information you should contact the Driving Standards Agency (DSA) or visit their website www.dsa.gov.uk or alternatively the Ministry of Transport at www.mot.gov.uk.