I note the Deputy does not specify the junction in question but I presume it refers to either a regional or local road in Finglas village.
The improvement and maintenance of regional and local roads in Finglas village is the statutory responsibility of Dublin City Council, in accordance with the provisions of Section 13 of the Roads Act 1993. Works on those roads are funded from local authorities' own resources supplemented by State road grants, where applicable. The initial selection and prioritisation of works to be funded is also a matter for the local authority. In addition, traffic management measures in Finglas are also the responsibility of the local authority.
Arising from the introduction of the Local Property Tax and the Government commitment that local authorities will retain 80% of the tax revenues, the four Dublin Councils became self funding for regional and local roads under the main road grant categories from 2015.