System for providing signalling and barrier functions, such as for regulation of road traffic, comprising a plurality of modules adapted so that they can be engaged with each other in respective lateral edge regions, each module presenting: - a central region (111, 121) developing in a first direction and with a front wall and a back wall developing upwards from a base region adapted for placement on the pavement, - two lateral regions (112, 122; 113, 123) that develop outwards from respective opposite lateral edges of said central region, in a second direction, backwards and forming a shape angle (α) non-orthogonal in relation to said central region (111, 121), whereby said central region (111, 121) and lateral regions (112, 122; 113, 123) are provided as a single piece and where the front and back walls are devoid of through openings, whereby said module presents said central region (111, 121) with a cross-section when seen in side view, of different shape and different dimension from the cross-section of the lateral regions (112, 122; 113, 123) when seen in side view, whereby said module further comprises module connection means (13, 14) adapted so that they provide removable connection with laterally disposed neighbouring modules, characterized in that said module presents a base part and a top part that extend along the extension of module in said first direction, and are provided as at least one of: - a single piece that confines a single interior space and presenting a single entry by means of ballast and fluid communication between said base and top parts, - in two separate pieces that confine two interior spaces provided with respective entries of ballast means, and in that said module connection means (13, 14) are provided on opposite lateral edge parts of said module, whereby one of said lateral edge parts is provided on said base part and the other lateral edge part is provided on said top part, and whereby one of said lateral edge parts presents a downwards-oriented tooth element, and the other lateral edge part presents an upwards-oriented cavity element, at a height and configured in corresponding manner to said tooth element, in a manner of male-female type connection, and whereby said entries of ballast means are adapted so that can be closed by said module connection means, in particular by said cavity element. - a central region (111, 121) developing in a first direction and with a front wall and a back wall developing upwards from a base region adapted for placement on the pavement, - two lateral regions (112, 122; 113, 123) that develop outwards from respective opposite lateral edges of said central region, in a second direction, backwards and forming a shape angle (α) non-orthogonal in relation to said central region (111, 121), whereby said central region (111, 121) and lateral regions (112, 122; 113, 123) are provided as a single piece and where the front and back walls are devoid of through openings, whereby said module presents said central region (111, 121) with a cross-section when seen in side view, of different shape and different dimension from the cross-section of the lateral regions (112, 122; 113, 123) when seen in side view, whereby said module further comprises module connection means (13, 14) adapted so that they provide removable connection with laterally disposed neighbouring modules, characterized in that said module presents a base part and a top part that extend along the extension of module in said first direction, and are provided as at least one of: - a single piece that confines a single interior space and presenting a single entry by means of ballast and fluid communication between said base and top parts, - in two separate pieces that confine two interior spaces provided with respective entries of ballast means, and - a single piece that confines a single interior space and presenting a single entry by means of ballast and fluid communication between said base and top parts, - in two separate pieces that confine two interior spaces provided with respective entries of ballast means, and in that said module connection means (13, 14) are provided on opposite lateral edge parts of said module, whereby one of said lateral edge parts is provided on said base part and the other lateral edge part is provided on said top part, and whereby one of said lateral edge parts presents a downwards-oriented tooth element, and the other lateral edge part presents an upwards-oriented cavity element, at a height and configured in corresponding manner to said tooth element, in a manner of male-female type connection, and whereby said entries of ballast means are adapted so that can be closed by said module connection means, in particular by said cavity element.