The National Roads Authority (NRA) has claimed that continuing discussions between it and the Department of Transport could lead to the reclassification of up to 500km of the State's dual carriageways as motorways.
Among the sections of road which might be reclassified on a "case-by-case" basis are existing or planned dual carriageways on each of the five main inter-urban routes, as well as some of the N11 and parts of the N18 along the Atlantic Corridor.
If approved by Minister for Transport Martin Cullen, the move, which would require proposals to amend existing legislation, would also entail an increase in the speed limit on the dual carriageways concerned from 100km/h to 120km/h.
The State's 400,000 provisional licence holders, who are not allowed to drive on motorways, are unlikely to be permitted to use the dual carriageways if reclassified.
A spokeswoman for the Department of Transport confirmed that discussions with the NRA on the matter are continuing. But she said these were at an "early stage" and declined to comment further on when any decision might be made.
Michael Egan, head of corporate affairs with the NRA, claimed discussions with the department are at an "advanced stage". He said: "We think they see the merit of our suggestions, and we are optimistic proposals will emerge."
The NRA estimates that up to 500km of the current national road network could be reclassified as motorways.
As dual carriageways are already being built to motorway standard, Mr Egan claimed this means they can safely allow for speeds of up to 120km/h. This would allow for journey times on the roads in question to be cut.
The NRA believes that another key benefit would be to prohibit housing and other development activity along existing and planned dual carriageway routes.
Such development is currently prohibited along motorways, and if applied to dual carriageways, might ensure that "inappropriate" future development does not take place along these routes, the NRA maintains.
The NRA's research indicates that limiting the number of turns off a dual carriageway into or from such developments could impact significantly on the number of accidents which occur, and would decrease travel times along the routes.