What is the minimum distance you must maintain from the vehicle in front?

The situation takes place on a motorway, as indicated by the visible A4 road sign. According to the regulations, on motorways and expressways, the driver is required to maintain a distance from the preceding vehicle, expressed in metres, of no less than half the number representing the vehicle's speed in km/h. Therefore, when travelling at a speed of 80 km/h, a minimum distance of 40 metres must be maintained.