Early 1999: As traffic volumes rise the National Roads Authority considers replacing the existing N3 in a departure from previous proposals which were to improve the existing road.
2000-2002: New route designed as a motorway.
August 2002 Bord Pleanála hearing into proposed M3 .
August 2003 Bord Pleanála approves the route of new motorway.
March 2004 Test trenching begins along entire route and continues up to December.
July 2004: Test trenching reveals 38 significant sites in the 15km Dunshaughlin to Navan stretch of motorway .
May 2005 Minister for the Environment Dick Roche approves excavations clearing the way for the motorway to proceed.
May 2005 Save Tara Skryne Valley group announces it will challenge the decision in the High Court.
The NRA says construction could begin in 2006 and the road could be complete in 2010.
