As Minister for Transport, I have responsibility for overall policy and funding in relation to the national roads programme. Under the Roads Acts 1993-2015 and in line with the National Development Plan (NDP), the planning, design and construction, including noise mitigation measures, for individual national roads is a matter for Transport Infrastructure Ireland (TII), in conjunction with the local authorities concerned.
More generally, the Deputy may not be aware of the existing legislation in regard to environmental noise, including road noise, which does in fact require recurring assessments of the impact of noise.
Directive 2002/49/EC on the assessment and management of environmental noise was transposed into Irish law by the Environmental Noise Regulations, 2006. This legislation requires TII and local authorities to undertake strategic noise mapping every five years for all major roads carrying in excess of 8,250 annual average daily traffic (AADT). Noise maps identify and prioritise cluster areas which will require further assessment and may require mitigation measures to be put in place.
Once strategic noise maps have been produced, the results are used for each local authority to develop Noise Action Plans as required by the Environmental Noise Regulations. Under the Regulations, the Noise Action Planning Authorities are required to consult with the public when revising their current Plans.
I trust this information is of assistance to you.