Comments on Proposed Large Housing Developments in Dinas Powys

Barratts at site of St Cyres Lower School, top of Murch Crescent

United Welsh Housing Association at site off Caerleon Road, Murch



(sponsored by Dinas Powys Conservatives).

Full Planning Applications for these developments are expected to be submitted to the Vale Council shortly.  These comments cover points which could be made when this happens.

The current plans are for 220 houses at the St Cyres site and 70 houses at the Caerleon Rd site.

These estates will generate additional traffic both during construction and after occupation.  The only road access to both these sites is off the traffic light controlled junction on the strategic highway Cardiff Road (A4055) and up Murch Road.

The implications of extra traffic on Murch Road include:

  1. Safety – including the need for open access for Emergency Vehicles to and from the Health Centre and for residents living along the roads leading to the developments.
  2. Safety for school children entering and leaving Dinas Powys Infant School.
  3. Safety for residents of all ages crossing roads, particularly at the Murch Road / Castle Drive junction, and accessing the shops on Castle Drive.
  4. Added pollution along the routes.
  5. Increased noise along the routes.
  6. The impact on the already over-capacity strategic highway through Dinas Powys.

This last point probably represents the strongest case for objecting to each of the planning applications as explained below.  A further point relating to the disposal of sewage from the St Cyres site is covered later in these comments.


1 – Impact on Strategic Highway network

The new administration in the Vale were given no option but to sign into law at the end of June 2017 the Local Development Plan (LDP) compiled by the previous administration.  Policies SP7, MG16 and MD5 form part of the document.  Each contains requirements that relate to the impact of new developments on the strategic transport infrastructure and specifically on the highway network.

The relevant extracts are as follows:-

Policy SP7 – Transportation

The last paragraph states: ‘All new developments that have a direct impact on the strategic transportation infrastructure will be required to deliver appropriate improvements to the network.

Policy MG 16 – Transport Proposals

The last section under the sub-heading ‘Highway Improvement Works’ states:     ‘In addition, to mitigate the impact of development on the highway network, highway improvement works in the form of corridor or junction improvement schemes will be required.’

Policy MD 5 – Developments within Settlement Boundaries

Dinas Powys and Sully are among the LDP’s listed Settlements.  The second sentence of this Policy states: New development within these settlements will be permitted where the proposed development:  ’  There follows a list of various ‘do’s’ and ‘don’t’ points, including at number 6:  ‘Has no unacceptable impact on the amenity and character of the locality by way of noise, traffic congestion and parking.

These Policies mean that no new development will be permitted if it would result in an adverse or unacceptable impact on the highway network.  So, in order for a new development which would have such an impact to gain planning permission, appropriate highway improvement works would need to be implemented first.

The strategic road junction nearest the St Cyres and Caerleon Road developments is the Cardiff Rd / Murch Rd traffic light junction.

To identify the severity of the impact these developments could have on this junction, we have looked at the following traffic studies

  1. Capita Symonds – Highway Impact Assessment (HIA) for Vale Council, August 2013.
  2. Asbri Transport – Transport Statement for United Welsh Housing Association, February 2015
  3. RPS Group – Transport Assessment for Barratt Homes South Wales, August 2017

Traffic count surveys were carried out in December 2012 for the HIA and in September 2015 for Barratt’s St Cyres development.  Asbri’s report appears to have used the HIA’s 2012 traffic figures for this junction though they did counts in 2013 and 2015 for the Castle Drive / Conway Close and Murch Rd / Castle Drive junctions.

All three studies show that the Cardiff Rd / Murch Rd / Millbrook Rd junction was close to or over capacity at the start of the study period.  This is illustrated by the following figures for PRC (Practical Reserve Capacity ) and for the number of cars queueing on Murch Road back from the traffic lights.  PRC is a measure of the spare capacity at a road junction.  A negative PRC in red indicates that a junction is over capacity.

All figures are based on the pedestrian lights working on each cycle which is usual when children are being taken to or from the Infant’s School on the corner of this junction.  However, for comparison, the PRC figures with no pedestrian light delays are shown in brackets.

Study HIA for Vale Council (2012) Asbri for Caerleon (2015) RPS for St Cyres  (2015)
PRC during morning peak -18.7% (7.8%) 16.2% (42.7%) 11.0% (36.6%)
PRC during afternoon peak -46.7% (-5.7%) -6.6% (15.6%) -1.5% (16.4%)
Murch Rd morning queue 27 cars 13 cars 10 cars
Murch Rd afternoon queue 70 cars 12 cars 11 cars

The Vale-commissioned HIA study shows the junction is over capacity to a greater amount and with longer queues on Murch Road in 2012 than the studies for developers show in 2015.

All studies assess the future traffic situation taking into account general growth, committed development and planned developments such as at Caerleon Rd and St Cyres.  The HIA and Asbri give projected traffic figures for 2026 and 2028 respectively while the RPS study only looks as far ahead as 2020.

What all studies show is that traffic congestion at the Cardiff Rd / Murch Rd / Millbrook Rd junction will be significantly worse in the future if these developments are completed without improvements to the highway network.  The extent of this deterioration is illustrated by the following figures from these reports.

Study HIA for Vale Council (2026) Asbri for Caerleon (2028) RPS for St Cyres  (2020)
PRC during morning peak -91.8% (-40.4%) -19.6% (18.4%) -22.7% (-0.1%)
PRC during afternoon peak –84.6% (-33.5%) -43.6% (-3.9%) -27.8% (-8.5%)
Murch Rd morning queue 94 cars 43 cars 49 cars
Murch Rd afternoon queue 181 cars 54 cars 39 cars

It can be seen that all studies predict the junction will be significantly more over capacity in the future than in 2012 or 2015.  PRESS HERE for more details and figures from these reports.

The reports for both St Cyres and Caerleon developers attempt to play down the predicted future increase in traffic congestion at the Murch Road / Cardiff Road junction.

Both the Asbri and RPS reports consider that the actual situation is likely to be between the results with and without pedestrian light delays.  They also mention that the lights at this junction are operated by a system (termed MOVA) that changes the timings based on the traffic situations as they are forming.

The Asbri report therefore concludes ‘that the existing junction is likely to have sufficient capacity to accommodate both developments ….’

The RPS report notes that this junction ‘is currently operating close to its design capacity’ and that ‘the proposed development will have an impact on this junction although it is not considered to be severe.  It concludes that the proposed development of 220 dwellings …… can be adequately accommodated on the local junctions to the site.

But these statements by the Developers’ consultants do not change the fact that these developments do adversely affect this strategic highway junction by making it more congested in future and therefore do not comply with the LDP Policies referenced earlier.

So, unless adequate highway improvements are carried out, the planning applications for both the Caerleon and St Cyres developments should be rejected on the basis of non-compliance with the LDP.


2- Disposal of Sewage from the Developments

Welsh Water advise that disposal of sewage from the Caerleon site is not a problem.

Barratt’s plans for their St Cyres development show how they intend to deal with rain water drainage and with foul water drainage.  Rain water is to be drained into a large on-site holding tank and soak-away with overflow piped to a local watercourse.  This appears satisfactory.

However, Barratts plan for the site’s sewage to be drained to an upgraded pumping station near Sully Rd then pumped back to discharge into the head of the existing gravity sewer in Murch Crescent.

But in the documents listed below Welsh Water say that the existing Murch Crescent sewer does not have adequate capacity to take the flow from the development.  At the 10 August 2017 Exhibition, Barratts were unaware of this but have now been sent these documents:-

  • SD18 – VOGC and DCWW Statement of Common Ground (May 2015)
  • ID-2312-Welsh Water  – LDP Hearing Session 9  3 March 2016

Both these state: Our local sewer network is too small to accommodate the foul flows from this development.


3- Conclusion

The Dinas Powys By-Pass Steering Group will object to both planning applications on the grounds of non-compliance with the LDP and, in the case of the St Cyres site, have made this clear to Barratts.

We suggested to Barratts a week prior to the Exhibition that they should consider delaying their planning application until access could be provided to their site from the intended by-pass, but they were reluctant as no date has yet been given for the project.


1 thought on “Comments on Proposed Large Housing Developments in Dinas Powys”

Leave a Reply

Your email address will not be published. Required fields are marked *