xmlns:atom="http://www.w3.org/2005/Atom"
The effectiveness of a sign must not be adversely affected by:
5.1. the presence of another emission source of the same type which interferes with visibility or audibility; therefore, in particular,
5.1.1.the placing of too many signs too close together should be avoided;
5.1.2.two illuminated signs which are likely to be confused are not to be used at the same time;
5.1.3.an illuminated sign is not to be used in the proximity of another similar illuminated source;
5.1.4.two acoustic signals are not to be used at the same time;
5.1.5.an acoustic signal is not to be used if there is too much ambient noise;
5.2. poor design, insufficient number, incorrect positioning, poor state of repair or incorrect functioning of the signs or signalling devices.