Art. 16 Ordinance of September 5, 1979, on Road Signage (OSR) - Principles

Mandatory signs indicate an obligation or a prohibition; they generally have the shape of a disc. Prohibition signs typically have a red border and a black symbol on a white background; if they are matrix signs, the background may be black with a white symbol. Mandatory signs have a narrow white border and a white symbol on a blue background. If the signage is intended for short-term use, mandatory signs can be displayed on a foldable white signal of triangular shape.

Subject to any exceptional provisions regarding certain mandatory signs, the announced requirement applies at the location or from the location where the sign is placed until the end of the next intersection; at this location, the sign will be repeated if its validity needs to extend further. The signs "Maximum Speed" (2.30), "Minimum Speed" (2.31), "No Overtaking" (2.44), "No Overtaking by Trucks" (2.45), "No Stopping" (2.49), and "No Parking" (2.50) must be observed until the corresponding end of prescription sign (2.53, 2.54, 2.55, 2.56, 2.58) but at most until the end of the next intersection. The sign "Maximum Speed 50, General Limit" (2.30.1) applies throughout compactly built-up areas within localities (Art. 22, para. 3; Art. 4a, para. 2, OCR).

When a mandatory sign announces a requirement that must only be observed farther ahead, a "Distance Plate" (5.01) must be added; when a requirement is repeated, a "Reminder Plate" (5.04) must be added to the sign. Traffic prohibitions as well as weight and dimension limitations will be announced early enough to allow drivers to take a detour.

On long stretches, mandatory signs will either be repeated as needed at appropriate intervals, equipped with a "Reminder Plate" (5.04) for this purpose, or supplemented by the "Section Length" plate (5.03).