The system, known as VIPER, involves weight sensors actually embedded within the road surface (known as WIMS – Weigh-In Motion System) which measure the weight of each axle going over them to within 5% accuracy. The vehicle details are checked using ANPR (Automatic Number Plate Recognition) and the VOSA operative in front of his computer immediately takes the decision whether to request that the vehicle’s stopped and brought in for accurate weighing at the VOSA weighbridge.

During the trials of the system from June 2004 to December 2005 VOSA reported a 700% improvement in the accuracy of their vehicle stops for suspected overloading. Out of 434 vehicles identified by the system as being overweight, 379 were found to be actually overweight. Since the trials they have improved on their operating procedures and now report an almost 100% record in stopping overloaded vehicles.

There are apparently already 14 of these VIPER sites in use throughout the country and there are plans to introduce many more. Other than there being one on the M6 at Birmingham and the fact that VOSA have stated that there will be a “particular focus on port traffic” there seem to be few clues to exactly where these sites are located.

The bad news for couriers and other van drivers is that VOSA are actively targeting enforcement on light commercial vehicles because overloading is so common, particularly in the 3,500kg GVW range – overloaded Sprinter vans in other words.

So what can you do to avoid being caught breaking the law?

• Know exactly what weight your van can carry. Take your fully fuelled van, along with your maps, sack truck, ropes, straps and all the paraphernalia you carry, along to your local weighbridge and have it weighed (with you in it). Subtract that weight from the GVW of your van and the result is the weight you can legally carry.

• Know how heavy your load is. Don’t just take the customer’s word for it – if they’re wrong it will be you that’s prosecuted, not them. Many customers will give you the weight of the product rather than the weight of the product including containers and pallets. If you think you may be overloaded then drive to the nearest weighbridge to check your weight – you can’t be prosecuted for being overloaded if you’re on the way to the nearest weighbridge.

• Distribute your load evenly. You can be prosecuted for overloading individual axles as well as for being over your maximum allowed weight. Adjust your load so that the van sits evenly. If you’re driving along with the nose of the van pointing into the air then you probably need to shift some weight forward.

• Consider some sort of on-board weighing equipment – http://www.axtec.co.uk/On-board.htm for example, there are many other manufacturers.

It doesn’t automatically fine you – it just ‘suggests’ to the people at the checkpoint up ahead that it would be a good idea to stop a certain vehicle rather than pulling one at random.

It’s been used for the last 2 years apparently. A brilliant system as far as I can see.

Now I wonder how long it will be before they start using ANPR to catch drivers over their hours.