What is the minimum distance you must maintain from the vehicle in front of you when driving a 6-tonne lorry at the maximum permitted speed on this road?

The photograph shows a motorway, designated A4. On this type of road, the maximum permissible speed for a heavy goods vehicle with a Gross Vehicle Mass (GVM) of over 3.5 tonnes, and therefore also for the vehicle in the question, is 80 km/h. According to the regulations, on a motorway, a driver is required to maintain a minimum distance from the preceding vehicle, expressed in metres, of no less than half the number representing the vehicle's speed, which in this case is 40 metres.