An Bord Pleanala has decided to reject the recommendation of an inspector and deem that an environmental impact statement is not requred for proposed works at Blake's Corner.
The move clears the way for Clare County Council to push forward with its plans, but first it will have to overcome funding concerns.
An inspector on behalf of the national planning authority had raised concerns about plans to address traffic issues at Blake's Corner.
The Council's controversial plans involve the construction of a new bridge and inner relief road in Ennistymon, and also the removal of occupied homes and a business.
The protected but derelict Blake's and Linnane's Buildings would remain.
The inspector had flagged a number of issues, including the impact on other protected structures, but the call for an EIS to be conducted was rejected by four of the authority's five-person board.
A Natura Impact Statement is also not needed.
This decision allows the Council to progress the project, subject to the regular planning procedure, but funding for the project remains unclear.
In a separate development in July, Transport Infrastructure Ireland rejected the plans as an "interim solution" and local representatives are still awaiting a meeting to resolve the matter.
