Traffic levels on the N3 are low on all but the sections close to Dublin. The M3, which opened in 2010, seems overspecced for such levels. Since the traffic counters are located on the old N3, a drop is noticeable in that year.
The M3 opened in June 2010. It is currently posting a very low level of traffic for a motorway and has not succeeded in pulling a significant percentage of vehicles off the old road. This can be seen by comparing the above M3 figures to the old N3 Kells, Tara and Dunshauglin 2009/2010 figures at the top, which dropped following the road opening but only by around 20%. (Note, however, that the road was only open for the latter half of 2010). Additionally, it's notable how much the traffic level drops while passing between Dunboyne and Dunshaughlin. This huge fall from 30k to 13k cannot be accounted for purely by traffic exiting at the Pace interchange; clearly a high level of toll-dodging is taking place.