The A55 strategic road, situated in the north of Wales, United Kingdom, forms part of the TEN-T network Route E22. It carries inter-urban traffic from the UK and mainland Europe to and from Ireland, via the port situated at Holyhead. Many parts of the road are also used for commuting local traffic as well as seasonal traffic.
The A55 Tunnels (Conwy, Penmaenbach and Pen-y-clip) are situated in close proximity with each other along the route, close to the towns of Conwy and Llandudno. They carry up to 32,000 vehicles per day and are critical to the efficient mass movement of road traffic along the A55 route. The Penmaenbach and Pen-y-clip tunnels opened in 1989 and Conwy in 1991.
The A55 Tunnels Improvement Programme encompasses a range of different projects, which have given rise to the need for implementing ITS projects, alongside a range of other safety critical works. The projects involved were: Implementation of a North Wales Traffic Management System (NWTMS), Upgrade of Conwy Tunnel Generators, Conwy Tunnel Sump Improvements, Installation of a New Generator at Penmaenbach and Free Text VMS Improvements.