A465 Heads of the Valleys Dualling Sections 5 and 6 Dowlais Top to Hirwaun SUMMARY PROOF OF EVIDENCE. Highways Engineering Document WG 1.3.

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1 A465 Heads of the Valleys Dualling Sections 5 and 6 Dowlais Top to Hirwaun SUMMARY PROOF OF EVIDENCE Highways Engineering Document WG by Jonathan Thirkettle MARCH 2018

2 1. Introduction 1.1 I am Jonathan Thirkettle. I am a Highways Technical Consultant at Jacobs Engineering Ltd. I have 34 years experience in the design and construction of highway schemes. 1.2 I am the Highway Design Team Leader for the development of the A465 Heads of the Valleys Dualling Section 5 and 6 Dowlais Top to Hirwaun (the Scheme). 1.3 In preparing the draft Orders design I have been supported by my team of engineers. They have worked to my instruction and I adopt their work as my own and opinions I express are my own. 1.4 My evidence will address the highway engineering aspects of the Scheme. The evidence is true and the opinions express are my true and professional opinions. 2. Existing Road 2.1 In the 1960s highway improvements were made to the A465, straightening out the route and widening the then single carriageway to its current three lane carriageway configuration. The road generally has two lanes in uphill directions and one lane in the downhill direction. 2.2 In addition to the three lane configuration, this section of the A465 contains fourteen at-grade junctions of which four are roundabouts and the remainder are T-junctions or staggered crossroads. Jonathan Thirkettle / March 18 1 of 8

3 3. Scheme Proposals Overview 3.1 The proposed Scheme comprises of approximately 17.7km of primarily on-line carriageway widening. Proposals allow for the upgrading of the existing three-lane carriageway to rural all-purpose dual carriageway (D2AP) standard. There will be a short (approximately 1.4km) section of off-line construction west of Hirwaun, and a shorter off-line section (approximately 0.8 km) east of the Taf Fechan viaduct. Design Standards 3.2 The Scheme has been designed by reference to the standards as contained in the Design Manual for Roads and Bridges (DMRB). Relaxations and Departures from Standards 3.3 Physical constraints along the Scheme length require Departure from Standards for both the mainline and side roads. These Departures from Standards are at present being considered, informally, by the Welsh Government. Junctions 3.4 The Scheme includes six full movement grade separated junctions as follows (from west to east): - Hirwaun; - Croesbychan; - Baverstock; - A470; - Prince Charles Hospital; and, - Dowlais Top. Jonathan Thirkettle / March 18 2 of 8

4 Design Speed 3.5 A design speed of 120B kph has been selected for the full length of the Scheme. 3.6 In common with the other sections of the A465 adjoining Sections 5 and 6, the Scheme will be signed at the national speed limit. Non-Motorised User Provision 3.7 A segregated Non-Motorised User path would be provided adjacent to sections of the Scheme. Drainage 3.8 The Scheme drainage strategy has been developed to allow for surface water runoff from the highway corridor to be captured and attenuated such that discharge rates to watercourses are not increased. 3.9 Surface water attenuation would generally be accomplished by the use of ponds, or where this is not practical, by the use of underground tanks or oversized pipes Attenuation ponds are designed such that they will remain largely dry for the majority of the time i.e. they will only retain water for the immediate period after a rainfall event The Scheme crosses a number of minor watercourses and rivers. Flows would be maintained via either bridges, culverts or watercourse diversions. Road Lighting 3.12 Hirwaun junction would be fully lit with lighting provided on the mainline through the junction and on the slip roads The other junctions at Croesbychan, Baverstock, A470, Prince Charles Hospital and Dowlais would be partially lit with only the on/off conflict points lit as a minimum. Jonathan Thirkettle / March 18 3 of 8

5 3.14 The remainder of the Scheme would not be provided with road lighting. Road Restraint Systems 3.15 The Scheme would be provided with a vehicle restraint system (steel/aluminium safety barriers) where required in verges to protect motorists from any hazards including highway infrastructure, structures, rock faces and embankments The central median of the Scheme mainline would be provided with a permanent vertical concrete safety barrier for the full length of the Scheme. Pavement 3.17 The majority of the mainline would have low-noise surfacing. Between Croesbychan and Baverstocks (where noise impact is not as significant an issue as for the remainder of the Scheme) and at junctions, more durable surfacing could be used. Intelligent Transport Systems and Communication Apparatus 3.18 Four 100mm diameter ducts are to be provided for the entire length of the Scheme. At structures, two 150mm diameter ducts are to be provided Four 100mm diameter cross-carriageway connector ducts are to be provided across the mainline at approximately every 500m Two longitudinal blown fibre cables are to be installed within the mainline verge for the length of the Scheme. The blown fibre cables are to be located within one of the 100mm diameter longitudinal ducts Five variable message signs are to be provided throughout the Scheme. Jonathan Thirkettle / March 18 4 of 8

6 Lay-Bys and Maintenance Bays 3.22 The Scheme would be provided with two lay-bys in each direction. Laybys would have a full standard Type A layout with taper diverge and kerbed segregation island Emergency roadside telephones are proposed at each of the lay-bys Police Observation Platforms (POPs) would be provided at the back of the four proposed lay-bys. Whilst not generally a requirement for D2AP type roads, the inclusion of POPs has been at the request of the Welsh Government. Signs and Road Markings 3.25 Junction Advanced Direction Signing (ADS) would be based on a twosign junction approach. Side-road signage is more typically based on a single-sign ADS approach In additional to directional signage, the Scheme would be provided with regulatory and information signage All mandatory signage would be illuminated. Non-illuminated signage would be reflectorised All Scheme road signs and road markings would be bilingual. 4. Differences to the made Line Order Overview 4.1 The made Line Order (1999) for the A465 Abergavenny to Hirwaun dualling shows the entire route of the main new A465 trunk road. The draft Amendment Order provides for changes that are required to achieve the Sections 5 and 6 Scheme. The amendments to the Line Order are summarised as follows.: Slight relocation of the Hirwaun roundabout due to the presence of an existing gas main; Jonathan Thirkettle / March 18 5 of 8

7 Provision of a new full movement grade separated junction at Croesbychan; Introduction of a split alignment at Nant Hir; Updated junction layout at Baverstock; Removal of westbound climbing lane between Baverstock and the A470; Development of junction layout at the A470/A465 intersection; Removal of split junction at Gurnos and provision of a full movement grade separated junction at Prince Charles Hospital. Hirwaun Junction 4.2 This change resulted in a south-easterly shift of the new Hirwaun junction when compared to 1999 Line Order plan in order to avoid a trunk gas main. An additional re-configuration of the Tower Road realignment has also been introduced. Croesbychan Junction 4.3 The 1999 Line Order made provision for the removal of the existing access to the A465 at Croesbychan. However, options for the introduction of a grade-separated junction at Croesbychan were assessed following a series of Public Information Exhibitions (PIEs) in December The provision of a grade-separated junction at Croesbychan also provides a means of incorporating the proposed Cynon Valley Gateway (Aberdare Bypass) Scheme being promoted by Rhondda Cynon Taf County Borough Council. Jonathan Thirkettle / March 18 6 of 8

8 Split Alignment at Nant Hir 4.5 Following Optioneering workshops it was deemed more cost-effective to introduce a split alignment over the Nant Hir Reservoir (with the retention of the existing bridge structure to take westbound traffic and a new structure to take eastbound traffic). This is in comparison to the 1999 Line Order which made provisions for a widening of the existing structure to take both east- and westbound traffic. Baverstock Junction 4.6 The significant change at the Baverstock junction is the inversion of the dumb-bell junction configuration. The 1999 Line Order showed the mainline passing beneath the dumb-bell link road in a substantial cut. Due to the necessity to reduce the amount of excavation in rock, the mainline is indicated in the current design as passing over the link road on embankment. 4.7 Additionally, Swansea Road is indicated as running parallel with the mainline to connect into the southern dumb-bell roundabout in the current version of the design. Removal of Climbing Lane 4.8 The 1999 Line Order made provision for a climbing lane and downhill arrestor bed between Baverstock and the A470 junction. 4.9 Design development has incorporated improvements to the vertical alignment of the proposed highway. As a result, it has been determined that both the climbing lane and the arrestor bed are no longer required. A470 Junction 4.10 Relatively minor amendments have been made from the teardrop junction configuration included in the 1999 Line Order to allow for full movement at both of the dumb-bell roundabouts. Jonathan Thirkettle / March 18 7 of 8

9 Removal of split junction at Gurnos and provision of a full movement grade separated junction at Prince Charles Hospital, Gurnos 4.11 Half-junctions at Gurnos and Galon Uchaf included in the original 1999 Line Order have been replaced with a full-movement junction at Prince Charles Hospital. This change significantly improves traffic flows within Gurnos and Galon Uchaf as it provides a connection to the proposed link road to Pant Industrial Estate, removing heavy goods vehicles from the Gurnos Ring Road. Updated slip road provision at Dowlais 4.12 In comparison to the 1999 Line Order, the eastbound diverge and westbound merge at Dowlais have been shifted outwards to allow space for the dual carriageway to be routed through the junction. 5. Conclusion 5.1 The proposed highway has been designed by reference to the geometric design standards contained the Design Manual for Roads and Bridges. However, Departures from Standards have been identified and are deemed necessary due to physical and environmental constraints. 5.2 As the Scheme design has developed, the design team have consulted with statutory bodies, landowners and local residents. The comments and suggestions received have been assessed and incorporated into the Scheme design where appropriate. 5.3 The highway engineering design meets the requirements of all road users including cyclists, pedestrians and other non-motorised users. 5.4 Land identified in the draft Compulsory Purchase Order is only that which is essential for the Scheme. Jonathan Thirkettle / March 18 8 of 8