A470(T) Dolwyddelan to Pont-yr-Afanc
The Dolwyddelan to Pont-yr-Afanc Improvement is the second stage of a programme of improvements of the Cardiff to Glan Conwy Trunk Road between Blaenau Ffestiniog and Bettws y Coed. The whole length of the improvement lies within an area of internationally recognised scenic value.
The landscape architects' role as 'concept guardians' was to ensure that the underlying landscape design philosophy and vision was implemented. Environmental concerns have driven the agenda right from the scheme's conception and have informed the entire construction process.
The project demanded innovation from the outset, with reduced environmental disturbance achieved by adopting features such as lower design speeds and narrower verges to reduce the width of the road corridor. The existing trunk road was narrow with a tortuous alignment and the carriageway often constrained between stone walls. In several locations long and/or wide vehicles travelling in opposite directions had difficulty in passing each other causing significant delays, a situation aggravated during the summer months with an increase in coaches and caravans. The accident rate was above the national average for a rural trunk road with the road frequently blocked following an accident or incident, causing congestion and difficulties for the emergency services and road users. Verges were largely non-existent and visibility poor, resulting in particularly difficult passage for pedestrians, cyclists and equestrians.
The improvement was to address these problems, widening the existing road with some easing of the sharper bends. It was to accord with current trunk road and local transport policies, whilst taking into account the important environmental issues. This trunk road is a vital highway link for Wales and the balance between improved road safety and journey time reliability whilst retaining a genuine focus on environmental protection, mitigation and enhancement was a key client requirement.
The improvement was to be designed to integrate the road into the surrounding landscape and to avoid long term detriment to areas adjacent to the road.
| Location | Snowdonia National Park, Wales |
| Type of scheme | Highway redesign |
| Size | 7.2 km |
| Lead landscape architect | WYG Environment Planning Transport |
| Outline brief | Road-widening, safety improvements and integratation of the road into the surrounding landscape. |
| Contract value | £17.5m |
| Completion date | 2005 |
| Awards | Highly Commended 2007 LI Awards Design over 5ha |
Technical summary |
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| Materials | The scheme has 3,500m of new retaining walls; innovative retaining wall solutions to cope with height (up to 7m), variable ground conditions, space restrictions, and environmental constraints, including the use of concrete panels with inclined anchors founded on rock or on piles bedded into the rock. All walls were then masonry faced. |
| Category | Transport |
| Keywords | engineering - transport - rural areas |
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