The warning triangle has a trapezoid base part supported on feet, and a triangular upper part connected to the base part by a pivot. The upper part is able to be moved between the erected and collapsed positions relative to the base part. The pivot (16) is located close to or on the vertical central axis of the triangle (11). The pivot may be in the upper edge region of the base part. The upper part may be able to turn for at least 180 degrees round the pivot. There may be a centre gap (26) bridges by at least one web (17a,17b) extending from the pivot.
