Some traffic signs are only intended for motorcycles: C6 (no quads allowed), C7 and E9i. But be careful, there are also signs that depict a car and apply to motorcyclists.
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C7
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Ban on motorcycles
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C5
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Ban on motor vehicles and other multi-lane motor vehicles
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C35
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No overtaking for all types of vehicles
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E9b
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Parking for motorbikes, cars and minibuses only
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E9i
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Parking for motorbikes only
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Other important road signs to consider:
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A51
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Danger not defined by special symbol
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A17
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Loose gravel
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A1a
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Dangerous bend
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A13
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Uneven road surface
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A14
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Road hump(s)
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A15
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Slippery road
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