Owain wrote: ↑Sat Apr 02, 2022 11:18
Euan wrote: ↑Sat Mar 16, 2019 22:23
Graham wrote: ↑Sat Mar 16, 2019 16:57
I'm a little curious as to why the road has been put in this corridor. A casual look a map suggests an alterative of building a motorway from Limerick to Cahir, with a spur motorway (cutting off the corner) between Mitchelstown and Tipperary. This would provide a good link between Cork and Limerick, and would also improve the route between Limerick and the towns (and ferries) in the southeast.
Is there something I am missing here? Would this overload the M8 south of Mitchelstown? Is the land north of Mitchelstown too difficult to build a road through?
I doubt it would be numbered M20 if it had been planned to link Limerick to Cahir, i.e. along the corridor of the N24.
For a Limerick - M8 connection this would be the most sensible route to take, but for Limerick - Cork traffic it would be a big detour compared to the route of the N20.
I'm not sure it would be a 'big' diversion! There are plenty of other examples in Britain and continental Europe where motorways have been planned so as to minimise the amount of construction and cost, by employing such diversions; and it's not like Ireland is a huge country with the diversion adding hundreds of kilometres to the journey.
I agree. But I'd suggest a direct route from the M8 at Mitchelstown to the M20 at Limerick. This is 47km compared to about 75km as-the-crow-flies for Cork to M20 along the N20 corridor. It would be barely less direct for Cork to Limerick. The route would go west of the Galty Mountains rather than through them (!).
A Limerick to Waterford motorway could use the Limerick to Mitchelstown section, then multiplex with the M8 for 15km, before cutting the corner for the N24 corridor towards Waterford. This would require an additional 60km of motorway, compared to 105km for the full N24 corridor motorway. So the total new motorway construction for Cork to Limerick
and Waterford to Limerick is 47km+60km=107km, compared to 75+105=180km if you built along the N20 and N24 corridors.
The point about the M8 south of Mitchelstown maybe needing widening in this scenario is reasonable, but even if the whole lot would have to be done that would only be another 47km, so substantially less than the extra 73km of new motorway required with the N20/N24 corridors. The cost and environmental impact would be significantly lower due to the shorter distance and the fact it's widening rather than new motorway
A further advantage is that, as you cut the corner between the N24 and M8 south of Cahir, you get a perfectly serviceable Waterford to Cork motorway bundled in!
The main problem with the proposal is that the Limerick to Waterford route would be about 120km compared to about 105km with a motorway all along the N24 corridor. But the extra 15km is quite minor given the significant advantages.
(All distances are 'as-the-crow-flies' - obviously in reality both my suggestion and the N20/N24 route would be longer as they have to zig zag to avoid settlements etc.)