This is an old question that is no longer in use.
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What shape is the most common for prohibitory signs?
No motor vehicles with a connected trailer (C6)
”The sign indicates a prohibition against motor vehicles with a connected trailer of a type other than semi-trailer or centre axle trailer. If the prohibition also applies to motor vehicles with a connected semi-trailer or centre axle trailer, this will be indicated on an additional panel. If the prohibition only refers to vehicle combinations with a trailer whose total weight exceeds a certain tonnage, this will be indicated on additional panel T5, total weight.”
No bicycles or class II mopeds (C10)
”If the prohibition also applies to class I mopeds, this is indicated on an additional panel.”
There are also a few square ones, such as:
Turning area (C42)
”The sign indicates an area intended for turning a vehicle and that parking is prohibited here. If sign C39, no stopping or parking, is added to the sign, it indicates that both stopping and parking are prohibited.”
There is also a driving licence book online (2023).
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