You are driving on the motorway in a motor vehicle with a gross vehicle weight rating in excess of 7.5 t. The heavy snowfall has reduced visibility to less than 50 m. What must you do?

The selected combination of answers is correct because, under German traffic regulations, when driving a heavy vehicle in conditions of reduced visibility, it is crucial to prioritize safety.

1. Not using the extreme left-hand lane: This rule helps prevent overtaking and promotes safety when visibility is severely limited. The left lane is typically reserved for faster-moving traffic, and heavy vehicles are advised to stay in the right lanes unless overtaking.

2. Speed limit of 50 km/h: In reduced visibility conditions, it's essential to lower your speed to respond safely to any unforeseen obstacles or hazards on the road. This speed limit is a precautionary measure to ensure drivers have adequate reaction time.

Leaving the motorway is not necessarily required unless conditions worsen, but retaining safety measures through the first two choices is vital for ensuring road safety in adverse weather conditions. Understanding these rules helps in maintaining safety not only for yourself but also for other road users.