Route :

The Chester Southerly Bypass :

The A55 runs west from its junction with the M53 motorway near Chester, where it is known as the Chester Southerly Bypass, crossing the River Dee and the Welsh border before passing close to Broughton then passing north of Buckley and Northop. There is a major climb westbound between Broughton and Buckley (Junctions 35a to 35) though with no crawler lane. There is a difficult junction with the A494 at Junction 34/33b and the road briefly has a three lane section as traffic joins from Queensferry and leaves towards Mold. In the eastbound direction there is also a short three lane section for the same reason. There is also a 270 degree speed limited curve to climb up and over the A55/A494. There are plans that may affect this often congested junction as part of the A494 Queensferry to Ewloe improvement.

Ewloe to Colwyn Bay :

Climbing up Rhuallt hill eastwards.
From Ewloe, the road climbs up onto the flanks of Halkyn Mountain passing to the south of Holywell with major climbs between Northop and Halkyn (Junctions 33 and 32b) and Halkyn and Holywell Summit (Junctions 32 and 31). This section of road is notorious for poor weather conditions including fog, ice and snow in winter months. In fine weather this section provides extensive views over the Dee estuary to the Wirral Peninsula, Liverpool and beyond. The steep descent towards St Asaph is down the new Rhuallt Hill (Junctions 29 to 28), which also provides the first views of the mountains of Snowdonia in the distance. There is a crawler lane on Rhuallt Hill for eastbound traffic. The road bypasses St Asaph to the north and runs along the North Wales coast passing Abergele.

Colwyn Bay Bypass :

Part of the route (Junction 23) Llandulas to (Junction 17) Conwy is signed as a 70 mph (110 km/h) speed limit (as opposed to most of the other sections of the A55, which are the National Speed Limit) and is a non-motorway special road, which has restrictions on access by pedestrian and other traffic, similar to the restrictions applied to a motorway. There is also a stretch passing through Colwyn Bay (Old Colwyn to Mochdre) signed as a 50 mph (80 km/h) limit. These restrictions are imposed as added safety precautions because the slip-roads in this stretch are unusually short because of the difficulty of fitting the road into a very narrow area of land, and, due to the road underpassing much of the town, to reduce road surface noise levels.

The Conwy Tunnel :

Approaching the tunnel from the west.
The crossing of the estuary of the River Conwy is by means of an immersed tube tunnel that was constructed as pre-formed concrete sections and then floated into position over a pre-prepared trench in the bed of the estuary. The use of a tunnel followed an extensive public consultation which ruled out another bridge on aesthetic ground since it would have damaged the view of the world heritage site Conwy Castle and the two bridges by Robert Stephenson and Thomas Telford. Because of the valuable fishery in the river and also because of the history of heavy metal mining in the catchment of the river, extensive ecological assements were made both prior to the construction of the tunnel and subsequently. These studies finally concluded that no significant environmental damage had been caused. Another alternative bridge crossing was proposed at Deganwy but this too was ruled out for aesthetic reasons. An inland alternative with heavy grades, following the old Roman road, was also worked up as part of the Collcon Feasibility Studies but rejected for cost and utility reasons.

Penmaenmawr and Penmaenbach tunnels :

An easterly view of the A55 at Penmaenmawr with the North Wales Coast Railway on the seaward side. The Penmaenbach Tunnels are in the distance. Barrie Hughes
The construction of the coastal section of the road involved major civil engineering works, with hard rock tunnels passing through the cliffs in two places. In the Eastbound direction, the road still uses the 1930s cliffhugging route. The eastbound carriageway at Penmaenbach is subject to a 30 mph (50 km/h) speed limit due to sharp curves. Plans to rectify this by building another tunnel parallel to the current Westbound tunnel (as orignially intended when the westbound was proposed) have been discussed for several years. The original Telford road around the cliffs is now a cycleway at both locations.

Llanfairfechan to Anglesey :

The rest of the route is of lower standard than that of those further east. This is due to much traffic leaving for major holiday destinations such as Rhyl or Llandudno. As such part of the route is not classed as clearway and has two at grade junctions. The Bangor bypass, in which the road previously terminated and became the A5 regains high standards and is such through the Anglesey bypass, bar the Britannia Bridge, which is a single carriageway deck above the North Wales Coast railway over the Menai Strait. This section intersects with the A487 towards Caernarfon, and the west coast of Wales.

Anglesey :

Looking east along the road in Anglesey with the mountains of Snowdonia in the background.
The final section of the A55 to be dualled was the Anglesey section. This 20 mile (32 km) section extending right into Holyhead Harbour was constructed as Private Finance Initiative scheme where the builders, a Carillion / John Laing joint venture, earn a shadow toll based on usage and lane availability. They also have to maintain the road for the extended period of their shadow toll agreement. When travelling eastbound along this section there are fine views of Snowdonia.