Michael Hughes Bridge links the N4 National Primary Route with the N15 and the N16. Construction of the bridge commenced in July 1987 and it was opened to traffic in December 1988. It carries the N4 national primary road over the Garavogue River in Sligo city. The general topography around the bridge is level.
The surrounding areas are urban, with Sligo city centre to the southeast of the site and Sligo harbour immediately west of the bridge. The carriageway was 13.42m wide with footpaths approximately 3m either side.
Prior to the widening works there were two traffic lanes in each direction crossing the bridge, with a right turn pocket provided for northbound traffic wishing to turn onto Markievicz Road. There is a large right turn movement southbound over the bridge to Ballast Quay, and a dedicated right turn lane was provided to accommodate this.
[caption id="attachment_27048" align="alignright" width="300"] Intermediate support pier rebar construction for Hughes Bridge[/caption]
The bridge severely restricted traffic flow, especially that travelling in a southern direction. Lane swapping by traffic approaching the bridge was common and led to collisions. Tailbacks for traffic travelling southbound occurred daily with traffic backing up and beyond the N15/N16 junction, causing significant delays at peak times. The N4 at this location currently carries a traffic volume in excess of 27,000 AADT (3.4 per cent HGV).
A considerable investment was spent on the construction of the N4 Sligo inner relief road in recent years through Sligo city and environs. However, this investment was not being fully utilised at the northern end as a result of the restrictions on traffic imposed by the bridge structure. The widening works have helped to alleviate the difficulties with traffic congestion and have maximised the benefits of the inner relief road scheme.
The concept of widening Hughes Bridge originated with a project entitled N4/N15 Sligo to the county boundary, which was progressed through various planning stages from 2004 to 2010. The proposed route commenced at Hughes Bridge and tied into an existing improved section at the Co Leitrim boundary ‘Bunduff Bridge’.