ACFC/44DOC(2012)001 rev ‘substantial’ must be established by States Parties, such as for instance in the form of thresholds. While states have a margin of appreciation in determining the threshold, this must not be exercised in such a manner as to constitute a disproportionate obstacle with respect to certain minority languages. For instance, the Advisory Committee found that the requirement of an absolute or relative majority in urban, municipal or local communities raised concern in terms of its compatibility with Article 11 of the Framework Convention. 78 The relatively flexible wording of this provision stems from a desire to be able to take due account of the specific circumstances prevailing in the various States Parties. In addition, Article 11.3 also takes into account, where applicable, existing agreements with other states, without, however, establishing an obligation for states to enter into such agreements.79 66. The Advisory Committee always welcomes the lowering of thresholds. Since Article 11.3 of the Framework Convention refers to areas which have been “traditionally inhabited” by substantial numbers of persons belonging to a national minority, the demographic structure of the area in question should be considered over a certain period in order to ensure that more recent assimilation tendencies do not work against the preservation of the minority language.80 Therefore, authorities should interpret and apply legislation in a flexible manner without relying too strictly on the threshold requirement. 67. Article 11.3 of the Framework Convention requires that the display of signs in minority languages be given a clear and unambiguous legislative basis. It is not sufficient if this practice is granted as a matter of fact but unsupported by law.81 Road traffic safety or the use of different alphabets may not be used as arguments against bilingual signposts.82 On the contrary, bilingualism in signposts should be promoted as it conveys the message that a given territory is shared in harmony by various population groups.83 78 First Opinion on Bosnia and Herzegovina; Second Opinion on Poland. See Framework Convention for the Protection of National Minorities and Explanatory Report, H(1995)010, February 1995, paragraph 70. 80 Third Opinion on Austria. 81 First Opinion on Georgia. 82 First Opinion on Denmark. 83 Third Opinion on Italy. 79 21