A road safety barrier assembly comprising: a road safety barrier which extends along the side of a carriageway, in turn comprising: a plurality of re-directing elements for re-directing a vehicle which impacts against the road safety barrier; a plurality of support elements for supporting the plurality of re-directing elements; a plurality of sensors and/or light signalling sources; at least a part of the support elements of the plurality of support elements each comprising a cavity and being distributed along the road safety barrier; a plurality of electronic devices which are distributed along the road safety barrier, each of the electronic devices of the plurality of electronic devices being connected to a sensor and/or to a light signalling source of the plurality of sensors and/or light signalling sources and being housed in a cavity of a support element of the plurality of support elements; a plurality of electric cables which extend along the road safety barrier and which electrically connect each electronic device of the plurality of electronic devices; wherein each cavity of the support elements of the plurality of support elements is accessible from outside in order to enable replacement or repair of an electronic device of the plurality of electronic devices which is housed internally thereof; wherein each support element of the plurality of support elements which comprises a cavity also comprises: an opening for accessing the relative cavity from outside; and a cover for closing the opening which is removably fixable to the support element of the plurality of support elements which comprises a cavity; characterised in that: each support element of the plurality of support elements which comprises a cavity has a pole shape having a lateral surface at which the opening is afforded; each electronic device of the plurality of electronic devices, when housed in the cavity is arranged so as to face the opening. a road safety barrier which extends along the side of a carriageway, in turn comprising: a plurality of re-directing elements for re-directing a vehicle which impacts against the road safety barrier; a plurality of support elements for supporting the plurality of re-directing elements; a plurality of sensors and/or light signalling sources; at least a part of the support elements of the plurality of support elements each comprising a cavity and being distributed along the road safety barrier; a plurality of electronic devices which are distributed along the road safety barrier, each of the electronic devices of the plurality of electronic devices being connected to a sensor and/or to a light signalling source of the plurality of sensors and/or light signalling sources and being housed in a cavity of a support element of the plurality of support elements; a plurality of electric cables which extend along the road safety barrier and which electrically connect each electronic device of the plurality of electronic devices; wherein each cavity of the support elements of the plurality of support elements is accessible from outside in order to enable replacement or repair of an electronic device of the plurality of electronic devices which is housed internally thereof; wherein each support element of the plurality of support elements which comprises a cavity also comprises: an opening for accessing the relative cavity from outside; and a cover for closing the opening which is removably fixable to the support element of the plurality of support elements which comprises a cavity; characterised in that: each support element of the plurality of support elements which comprises a cavity has a pole shape having a lateral surface at which the opening is afforded; each electronic device of the plurality of electronic devices, when housed in the cavity is arranged so as to face the opening.