5.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 be used if there is too much ambient noise;