You are driving a tanker carrying petrol to Vlaardingen. In front of the tunnel stands a round sign with a red border and a diamond-shaped hazard symbol, without a number. What do you do?
You drive on: the sign only warns, so you drive carefully
You do not enter the tunnel: this sign closes it to your load
You drive on: the sign is about vehicles above a fixed length
Explanation
False — you confuse this sign with the length sign. The length sign always carries the number of the permitted length; this sign without a number closes the road to vehicles carrying certain dangerous goods (Book p.239-240).