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A55 road

A55 road shield

A55 road
The A55 at Warren Mountain.
Route information
Part of
Length: 87 mi (140 km)
Major junctions
East end: Chester
West end: Holyhead
Road network

The A55, also known as the North Wales Expressway (Welsh: Gwibffordd Gogledd Cymru) and the Chester to Bangor Trunk Road,[1] is a major road in Britain. Its entire length is a dual carriageway primary route, with the exception of the point where it crosses the Britannia Bridge over the Menai Strait. All junctions are grade separated except for two roundabouts — one east of Penmaenmawr and one in Llanfairfechan. The road originally ran from Chester to Bangor but was extended parallel to the A5 across Anglesey right into Holyhead Docks in 2001. The road improvements have been part funded with European money, under the Trans-European Networks programme, as the route is designated part of Euroroute E22 (Holyhead - Leeds - Amsterdam - Hamburg - Malmö - Riga - Moscow - Perm - Ekaterinburg - Ishim).


  • Route 1
    • The Chester Southerly Bypass 1.1
    • Ewloe to Colwyn Bay 1.2
    • Colwyn Bay Bypass 1.3
    • The Conwy Bypass 1.4
    • Penmaenbach and Pen-y-clip tunnels 1.5
    • Penmaenmawr to Anglesey 1.6
    • Anglesey 1.7
  • Planned improvements 2
  • History 3
    • A55 opening dates of major improvements 3.1
  • Services 4
  • Junctions 5
  • References 6
  • External links 7


The Chester Southerly Bypass

The A55 begins at the end of 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 , Penyffordd and Northop. There is a major climb westbound between Broughton and Buckley (Junctions 35a to 35) though with no crawler lane. Junction 34/33b is point at which the A494 converges and then diverges with the A55. The road briefly has a three-lane section as westbound traffic from Queensferry can leave towards Mold. In the eastbound direction another short three-lane section allows vehicles to join the A494 or exit onto the A55 to Chester. Traffic taking the A55 into England must negotiate a tight 270 degree speed-limited single lane curve to climb up and over the A55/A494. Plans to upgrade the A494 between this junction at Ewloe and Queensferry were rejected by the Welsh Assembly Government on 26 March 2008 due to their scale.[2]

Ewloe to Colwyn Bay

Climbing up Rhuallt Hill eastwards.

From Ewloe, the road is relatively flat until after Northop when it climbs up onto the flanks of Halkyn Mountain range, passing to the southwest 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, however there are extensive views over the River Dee estuary to the Wirral Peninsula, Liverpool and beyond. The highest part of the road is in the vicinity of Brynford at around 790 feet (240 m). 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 far distance. There is a crawler lane on Rhuallt Hill for eastbound traffic. The road bypasses St Asaph to the north, and runs past Bodelwyddan and Abergele to reach the North Wales coast at Pensarn (Junction 23A). From here onwards to Bangor, the route is close to the North Wales Coast railway.

Colwyn Bay Bypass

Two sections between (Junction 23) Llanddulas to (Junction 17) Conwy are signed as a 70 mph (110 km/h) speed limit because they are classed as non-motorway special roads. Unlike other sections of the A55 that have National Speed Limit (NSL) signage and are accessible to all motor vehicles, motorway restrictions (although it's not a motorway) apply on these stretches of road e.g. no pedestrians, learner drivers, farm vehicles etc. This is because these sections were built under legislation applicable to the building of motorways. But as they are not part of either the UK motorway network or are classed as an ordinary highway (public right of way), the national speed limit does not apply so 70 mph (110 km/h) signs (the maximum speed permitted on UK roads) are used instead.

A 50 mph (80 km/h) limit remains in force through the Colwyn Bay bypass (Old Colwyn to Mochdre). The restriction was imposed for several reasons. First as a safety precaution because the slip-roads on this stretch are unusually short due to the road's design. Part of it was built on a narrow swathe of land through the town that was once the North Wales coast railway; Colwyn Bay had to be rebuilt and the track bed realigned to complete the underpass. The former four-track railway was reduced to two more northerly tracks to make space for the road. Second the reduced speed limit was intended to reduce road noise for residents. However since the completion of the Colwyn Bay bypass, the lower speed limit has been an unpopular decision with drivers.[3]

The Conwy Bypass

Approaching the tunnel from the west.

The crossing of the estuary of the River Conwy is by means of an immersed tube tunnel, the first of its kind constructed in the United Kingdom.[4]

The decision to construct an immersed tube tunnel bypass followed an extensive public consultation, named the Collcon Feasibility Study. This ruled out another bridge by the castle on aesthetic grounds, since it would have damaged the view of the world heritage site Conwy Castle, and the two bridges by Robert Stephenson and Thomas Telford. Another alternative bridge crossing was proposed at Deganwy, but this too was ruled out for aesthetic reasons. An inland alternative with heavy grades which would have passed over Bwlch y Ddeufaen pass at 430 metres (1,410 ft), following the old Roman road, was also worked up but rejected for cost and utility reasons.

The tunnel was constructed by a Costain/Tarmac Construction joint venture,[5] as pre-formed concrete sections, and then floated into position over a pre-prepared trench in the bed of the estuary. The 3 million tonnes of silt and mud extracted to create the trench in which the tunnel sections sat, were vacuumed to one side of the construction site, as to let them drift down river would have harmed the large mussel fishing beds downstream. The silt was deposited upstream of the bridge at Conwy which created a large new area of low lying land which was subsequently given to the RSPB for a wildlife preserve. The casting basin for the tunnel sections was later converted into a new marina in the lower estuary. 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 assessments were made both prior to the construction of the tunnel and subsequently. These studies finally concluded that no significant environmental damage had been caused.

After five years of construction, the tunnel was opened in October 1991by Queen Elizabeth ll, the tunnel initially had an advisory 50 miles per hour (80 km/h) speed limit, but this was dropped in 2007 as accidents were rare in the tunnels.

Penmaenbach and Pen-y-clip 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

Leaving Conwy in a westerly direction, the construction of this section has involved major civil engineering works because it crosses two major headlands: Penmaenbach Point and Penmaenan Point. Work has involved the cutting of several hard rock tunnels beneath the sea cliffs.

The first to be built in 1932 was the Penmaenbach Tunnel which carried motor traffic to Penmaenmawr. Two smaller tunnels through Penmaenan Point, opened 1935, carried the road onto Llanfairfechan. This new route, carrying traffic in both directions, relieved the original coach road built by Telford in the early 19th century. Cut into the cliffs by hand, this narrow, winding route hugged the contours around both steep headlands. Telford's route has now been converted into a cycleway across Penmaenbach and Penmaenan Points. Originally at the western end (Llanfairfechan) of the modern Pen-y-Clip tunnel, access was only allowed in an easterly direction because travelling the other way would mean heading the wrong way up the eastbound carriageway. However in 2011 a purpose-built bridge - over the westbound carriageway - was constructed to allow unrestricted access to cyclists and walkers.

The 1930s alignment was used until a new two-lane Penmaenbach Tunnel opened in 1989 to carry westbound traffic. Eastbound traffic would now travel through the 1932 Penmaenbach Tunnel using both its original lanes. Four years later, work to build the Pen-y-clip tunnel was completed. Like at Penmaenbach it carried westbound traffic while the original road carried vehicles in the opposite direction. Both new routes were subject to an advisory 50 mph speed limit until these were lifted in 2007 as there had been few accidents.

However traffic travelling eastbound on the 1930s cliffhugging route still faced speed restrictions at both tunnel locations. For instance the eastbound carriageway at Penmaenbach is subject to a 30 mph (50 km/h) speed limit due to sharp curves and double white lines nominally preclude lane changing. Plans to rectify the awkward alignment by building another tunnel parallel to the current westbound tunnel (as originally intended when the westbound tunnel was proposed) have been discussed for several years. The Recent work (late 2007) at Penmaenbach eastbound has seen the erection of gantries to close lanes when bidirectional working is in place.

Penmaenmawr to Anglesey

Some sections of the rest of the route are of lower standard than that of those further east. Some traffic leaves for major holiday destinations such as Caernarfon or the Llŷn Peninsula, though much continues on to the port of Holyhead. As such part of the route is not classed as clearway and has two at grade junctions (roundabouts), Penmaenmawr (Junction 16) and Llanfairfechan (Junction 15). The Bangor bypass, in which the road previously terminated and became the A5 regains high standards and is such through the Anglesey section, bar the Britannia Bridge, which is a single carriageway deck above the North Wales Coast railway over the Menai Strait. In 2007 the Welsh Assembly Government undertook a consultation to determine which of four options would be preferred for a second crossing. This section intersects with the A487 towards Caernarfon, and the west coast of North Wales.


Looking east along the road in Anglesey with the mountains of Snowdonia in the background.

The final section of the A55 to be constructed was the Anglesey section. This 20 mile (32 km) section from the end of the Llanfairpwll bypass to 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. The approach to Holyhead required major work with a new section over the sea paralleling the Stanley Embankment that carries the original A5 and the North Wales Coast railway.

Planned improvements

The Welsh Assembly Government (WAG) published its National Transport Plan in July 2009.[6] This includes mention of improvements to the A55 including the possible removal of the two roundabouts at Penmaenmawr and Llanfairfechan. In November 2012, the Welsh Government published two more detailed studies looking at options to improve transport in the North East Wales and the A55 / A494 areas.[7] Possible changes to be considered further include


The A55 partly follows the alignment of the Roman road from Chester (Deva) to Caernarfon (Segontium), particularly from Junction 31 to 30 and Junction 13 to 12. Between Chester and Holywell the alignment of this road is uncertain and between St. Asaph and Abergele, the Roman road followed an inland route avoiding the difficulties of the crossing of the Conwy estuary and the cliffs at Penmaenbach and Pen-y-Clip.

A55 opening dates of major improvements

  • Unknown date 1930s? Ewloe to Northop avoiding Northop Hall
  • Unknown date 1930s? Northop Bypass
  • Unknown date 1930s? Holywell Bypass
  • Unknown date 1930s? St. Asaph to Rhuallt dual carriageway
  • Unknown date 1930s? Short section of 'experimental' concrete road west of St Asaph
  • 1932 Penmaenbach Tunnel
  • 1935 Pen-y-Clip Tunnels
  • 1958 Conway new bridge avoiding Telford's suspension bridge
  • 1960s Tai'r Meibion to Tan-y-lon dual carriageway east of Bangor
  • 1964? Ewloe roundabout (part of the A494 Queensferry to Ewloe dualling, the 'Aston Bypass')
  • Unknown date 1965? Llysfaen dualling
  • 1968 Abergele Bypass
  • 1970 St. Asaph Bypass
  • 1975 Northop Hall Crossroads to East of Gables
  • 1976 Coed-y-Cra to Chaingates (Holywell)
  • 1976 Chester Southerly Bypass (terminating at Broughton)
  • 1980 Britannia Bridge and link roads
  • December 1980 Holywell By-Pass (Stage 1)
  • March 1981 Diversion East of Abergele
  • December 1983 Bangor By-Pass
  • Unknown Date Llanfairpwll By-Pass
  • September 1984 Hawarden By-Pass (from a point east of Broughton on the Chester Southerly Bypass to Northop Hall)
  • December 1984 Llanddulas to Glan Conwy (Colwyn Bay By-Pass, Stage 1)
  • June 1985 Llanddulas to Glan Conwy (Colwyn Bay By-Pass, Stage 2)
  • October 1986 Holywell By-Pass (Stage 2)
  • December 1986 Bodelwyddan By-Pass
  • June 1989 Penmaenbach Tunnel
  • June 1989 Northop By-Pass (Northop Hall to Halkyn)
  • October 1989 Penmaenmawr and Llanfairfechan By-Passes (excluding Pen-y-Clip Tunnel)
  • May 1990 Travellers' Inn Improvement
  • 1991 tunnel crossing of the River Conwy
  • June 1991 Extension of Chester Bypass to M53 (Junction 12)
  • May 1992 Rhuallt Hill Improvement
  • October 1993 Pen-y-Clip Tunnel
  • October 1994 Abergwyngregyn Improvement
  • 16 March 2001 Anglesey section (Llanfairpwll to Holyhead)
  • 2000/2004 Penmaenmawr eastbound slip road and grade separation at the summit of the Rhuallt Hill
  • 2004 Improvements to railway underbridges and cliffs at Penmaenbach (eastbound)
  • 2007 Alterations to roundabout at Llanfairfechan and bidirectional road indicators at Penmaenbach (eastbound)
  • 2008 New overbridge between Junction 32A and 32B for improved local access


There are two large services on the A55, along with numerous other petrol stations at the side of the road. The two major services are:

Bangor Services
(At J11) - Little Chef, Burger King, Travelodge, Esso, Costa Express

Gateway Services
Eastbound (After J33A) - Little Chef, Little Chef Express, Travelodge, Shell, Costa Express
Westbound (After J33B) - Costa Coffee, Subway, McDonald's, OK Diner, Holiday Inn, Shell, Costa Express, Deli2Go


A55 Road
km Westbound exits (B Carriageway) Junction Eastbound exits (A Carriageway)
0.0 Holyhead Ferry Port Terminus
[coord 1]
Start of Road
0.5 Holyhead Town centre A5154
Amlwch A5 (A5025)
Holyhead Town centre A5154
Amlwch A5 (A5025)
0.7 Trearddur Bay B4545 J1
Trearddur Bay B4545
A5153 J2 A5153
Caergeiliog, Valley A5
Amlwch A5025
J3 Caergeiliog, Valley A5
Amlwch A5025
Caergeiliog, RAF Valley, Bryngwran A5 J4 Caergeiliog, RAF Valley, Bryngwran A5
Bryngwran, Gwalchmai A5
Rhosneigr A4080
J5 Bryngwran, Gwalchmai A5
Rhosneigr A4080
Pentre Berw, Gwalchmai A5
Llangefni A5114
J6 Pentre Berw A5
Llangefni A5114
Gaerwen A5152 J7 Gaerwen A5152
31.3 No access
Llanfair PG A5
J7A No exit
Access only
Llanfair PG, Benllech A5025 J8 Llanfair PG, Benllech A5025
33.8 No access
Llanfair PG, Menai Bridge A5
J8A No exit
Access only
Britannia Bridge Bridge
[coord 2]
Britannia Bridge
Bangor, Menai Bridge, Ysbyty Gwynedd A487 J9 Caernarfon, Menai Bridge, Ysbyty Gwynedd A487
Caernarfon, Bangor A4087 J10 Bangor A4087
Bangor, Bethesda A5
J11 Bethesda A5
Talybont J12 Talybont
Abergwyngregyn J13 Abergwyngregyn
Llanfairfechan J14 Llanfairfechan
51.7 Llanfairfechan J15
Pen-y-Clip Westbound Tunnel (930 m)[9] Tunnel Two short tunnels
access only
No exit
J15A Penmaenmawr
56.2 Penmaenmawr J16
Dwygyfylchi J16A No exit
Penmaenbach Westbound Tunnel (658 m)[9] Tunnel Penmaenbach Eastbound Headland Tunnel(172 m)[9]
Conwy A547 J17 Conwy A547
Conwy Road Tunnel (1080 m)[9]
Restrictions apply
[coord 3]
Conwy Road Tunnel
Restrictions apply
Conwy (A547) J18 Llandudno Junction A546
Llandudno, Llanrwst A470
Llandudno Junction
J19 Llandudno, Llanrwst A470
Colwyn Bay (A547)
Llandudno Junction
Colwyn Bay, Mochdre, Penrhyn Bay B5115 J20 Colwyn Bay, Mochdre, Penrhyn Bay B5115
Colwyn Bay A547 J21 Colwyn Bay A547
Old Colwyn A547 J22 Old Colwyn A547
Start of Special road End of Special road
Llanddulas A547
Prohibited Traffic
J23 Llanddulas A547
Access only
No exit
J23A Pensarn, Abergele A548
No access
Abergele, Rhuddlan A547 J24 Abergele, Rhuddlan A547
84.6 no access
St. George, Towyn
J24A No exit
no access
Bodelwyddan, Ysbyty Glan Clwyd J25 Bodelwyddan, Ysbyty Glan Clwyd
St Asaph Business Park J26 St Asaph Business Park
St Asaph, Trefnant, Denbigh, Rhuddlan, Rhyl A525 J27 St Asaph,Trefnant, Denbigh, Rhuddlan, Rhyl A525
St Asaph A525 J27A No exit
No access
Rhuallt, Rhuddlan B5429 J28 Rhuallt B5429
Rhuallt J29 Rhuallt
Pen-y-Cefn J30 Pen-y-Cefn
Trelawnyd A5151
Caerwys B5122
J31 Holywell A5151
Caerwys B5122
no access
Holywell A5026
J32 Holywell A5026
Halkyn, Pentre Halkyn
No access
Pentre Halkyn J32A No exit
Access only
Halkyn J32B No exit
No access
Northop, Flint, A548 Coast Road A5119 J33 Northop, Flint, Mold A5119
116.5 No access
Connah's Quay B5126
J33A No exit
No access
No exit Northop Hall
120.0 No access
Mold A494
J33B No exit
Access only
Ewloe, Queensferry A494
Manchester (M56)
"Totso"[See notes]
Ewloe, Queensferry A494
Manchester (M56)
Hawarden, Buckley, Corwen A550 J35 Hawarden, Wrexham A550
Penyffordd J35A Broughton, Saltney A5104
128.5 no access
Broughton (A5104)
No exit
Access only
128.6 Entry into Wales Border Entry into England
Wrexham, Chester A483 J36 Wrexham, Chester A483
Access only
No exit
J36a Chester A5115
Whitchurch (A41)
No access
Nantwich, Northwich A51
Whitchurch (A41)
J37 Chester
Nantwich, Northwich A51
Start of road M53 J12
[coord 4]
Chester, Helsby A56
Non-motorway traffic
Chester, Helsby A56 Road continues as M53 to Wallasey
  • Data[10] from location marker posts are used to provide distance and carriageway identification information. Where a junction spans several hundred metres and the data is available, both the start and finish values for the junction are shown.
  • Totso = "Turn off to stay on" meaning that the driver must leave the main carriageway to stay on the specified (A55) route.
1.000 mi = 1.609 km; 1.000 km = 0.621 mi
Coordinate list
  1. ^ Start of A55 - Holyhead Ferry Port
  2. ^ Britannia Bridge - crosses the Menai Straits
  3. ^ Conwy Tunnel - Crossing of the Conwy Estuary
  4. ^ End of the A55 - becomes the M53


  1. ^ "The Chester to Bangor Trunk Road (A55), Talerdy Junction Phase 2, St Asaph - Environmental Impact Assessment".  
  2. ^ Welsh Assembly Government - Decision on A494 Drome Corner to Ewloe scheme
  3. ^ "50mph limit at Colwyn Bay should be scrapped say drivers". 7 June 2012. 
  4. ^ "Conwy Tunnel praised on 20th anniversary". BBC News. 25 October 2011. 
  5. ^ Motoway archive
  6. ^ Welsh Government | National Transport Plan
  7. ^ "Studies to improve transport in North East Wales published".  
  8. ^ "A55 A494 WelTAG Study – Stage 1 Appraisal" (PDF).  
  9. ^ a b c d "Tunnels". North Wales Trunk Road Agency. 2011. Retrieved 2011-09-04. 
  10. ^ "Resources". Traffig Cymru/Traffic Wales. Retrieved 2011-08-22. Select Telephone & marker post locations. 

External links

  • Traffic Wales - containing A55 webcams
  • SABRE Roaders Digest - A55
  • Images of diversion of North Wales Coast Railway at Colwyn Bay to accommodate A55
  • - 03/09/2004Engineers look at more A55 reliefBBC News -
  • The Motorway Archive - A55
  • The Chester-Bangor Trunk Road (A55) (Rhuallt Hill Improvement and Slip Roads) Order 1989 (S.I. 1989/2091)
  • Other Statutory Instruments pertaining to the A55
  • Roads UK: A55
  • North East Wales Area Based Transport Study November 2012
  • A55 A494 WelTAG Study – Stage 1 Appraisal November 2012
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