|Distance:||15.3 km (9.5 miles)|
|Meets:||N8, M8, N25, R623, R852, N28, R610, R853, R851, N27, R641, N71, R849, N22|
|Route outline (key)|
It starts at a junction with the N8 and N25 to the east of Cork, and almost immediately the entrance to the Jack Lynch Tunnel appears, and the road runs through this, underneath the River Lee, coming out 600 m later on the south-western outskirts of Cork city.
The slip road for the junction for the suburb of Mahon begins almost immediately after the tunnel. As this is also the location of Cork's largest out-of-town retail park ("Mahon Point"), traffic is often backed up here.
After the Mahon junction, there's major split with the N28 heading towards the passenger and freight ferry terminal at Ringaskiddy, and (rather indirectly) the suburb of Douglas, a destination which merits two exits further west on the other carriageway, but none on this.
Those wanting to go to Douglas who didn't take the Ringaskiddy exit, will get the sinking feeling of driving past the village on an elevated section of the road with no access, before reaching the Kinsale Road Interchange where the N27 between Cork Ciry and Cork Airport crosses the N40. At this point there are four lanes of traffic, the rightmost two of which will continue over the flyover and westwards.
Until a major re-engineering of this junction in late 2006 added a flyover and more parallel lanes, this junction used to be known locally as the "Magic Roundabout", where traffic from five major arms all met, and battled each other to get across a large, heart-shaped, light-controlled "roundabout".
The scale of the rework can be seen by the fact that at a point just west of the new flyover, there are now thirteen parallel lanes of traffic, making this the widest stretch of road in Ireland.
The reworking of the Kinsale Road Interchange has also subsumed the formerly standalone LILO junction for the suburb of Togher, beyond which there is one more roundabout (Sarsfield Road Roundabout) providing access to the suburb of Wilton and the Cork University Hospital.
Cork city is now behind us, although we're very much still in its commuter belt - officially this section is the Ballincollig Bypass (Ballincollig is a long, strung-out commuter town on the western side of Cork, which used to straddle the old N22).
The N40 ends unceremoniously where the N22 Cork to Tralee route joins the mainline just east of the satellite town of Ballincollig. The remainder of the mainline of this Ballincollig Bypass scheme is the N22, which continues into North-west Cork county and onwards to Co. Kerry.
There were plans for a complete ring road of Cork city linking from the M8 north of Glanmire around to the end of the Ballincollig bypass that were announced in 2007. However, this was put on hold after the recession.
- New Cork bypass opened (1985)