From the Mullingar bypass to Edgeworthstown, the road is a wide single-carriageway with hard shoulders.

This section of the road consists of three roundabouts and a Type 2 dual carriageway, i.e.: two lanes in each direction and no hard shoulder.

The road becomes a high-quality single carriageway bypass 3  km outside of Boyle town, with periodic alternating overtaking lanes passing Lough Key Forest Park and Ballinafad until it reaches Castlebaldwin.

[2] The road becomes near-motorway standard dual carriageway again at Collooney, approaching Sligo town.

[citation needed] The PPP contract was awarded in March 2003 to the EuroLink Consortium (SIAC Construction Ltd and Cintra - Concesiones de Infraestructuras de Transporte S.A.) and allows for them to collect tolls for 30 years from that date.

This tolled section (from Kilcock to Kinnegad) opened on 12 December 2005, almost a year ahead of schedule.

In the 1 July 2006 edition of the Meath Chronicle it was claimed that up to 10% of the €420 million road project had "to be ripped up and replaced" shortly after it opened due to rushed construction,[citation needed] however this cost would have had to be carried by the toll operators, not the state, as per the contract.

On 28 August 2009, the Department of Transport implemented the second round of proposed reclassifications of dual carriageways as motorways under the Roads Act 2007.

Private accesses and some left turns remain which prevents the section from being designated a motorway.

In 2013, a 5 km stretch of dual carriageway with at-grade crossover junctions between the M4 and the Mullingar bypass was upgraded to HQDC.