PUBLIC INQUIRY QUESTION - bailey.persona-pi.com

1 m4 corridor around newport PUBLIC INQUIRY QUESTION . REFERENCE NO. : PIQ / 019. RAISED BY: The Inspectors DATE: 20/02/17. RESPONDED BY: Ben Sibert DATE: 10/03/17. SUBJECT: Engineering Proof of Evidence Elucidations The attached document provides updates to provide responses to questions of elucidation raised by Mr Wadrup in correspondence dated 20 February 2017. Welsh Government m4 corridor around newport Proof of Evidence Engineering POE Elucidations Engineering Proof of Evidence Elucidations Ben Sibert, BEng CEng FICE MIStructE MCIHT. Welsh Government, Engineering Design Contents 1. Introduction .. 2. 2. Clarifications.

2 2. March 2017. Page 1. Welsh Government m4 corridor around newport Proof of Evidence Engineering POE Elucidations 1. Introduction This document provides updates to provide responses to questions of elucidation raised by Mr Wadrup in correspondence dated 20 February 2017. 2. Clarifications Evidence Section : QUESTION : Given that the INQUIRY will need to justify the CPO of land necessary for the construction of the road, what justification is there in the provision of a dual carriageway rather than a single carriageway which would cater for the traffic demand? Am I. correct in seeing this link road as one simply connecting to gyratory junctions rather than linking to unimpeded dual carriageways?

3 Evidence Section : Response: I have clarified in my evidence in section that the reason for the choice of a dual two lane link road is on the basis of a) Strategic WG decision and b) to be broadly consistent with the advice of TD 9/93. At The Plan stage of the Scheme, the Glan Llyn link was established as a dual lane highway as shown in the Stage 2 Scheme Assessment Report Volume 2, Drawing No. M4OA-01-00-DR- C-XX-0164 Section C sheet 1 of 3. Matthew Jones has explained further the strategic reasons for the choice of a dual two lane carriageway. Evidence Table 3: QUESTION : a) Traffic forecasting report figure It is not clear what the do-something flows are predicted to be on the length of the proposed motorway between junction 23 and 23 A.

4 These are quoted at 15,400 and 20,300 vpd east and westbound, but that seems to be impossible looking at the adjacent figures. b) I cannot reconcile table 3 in the proof with figure in the report. For example, J23-Glan Llyn is shown as 52,200 vpd in the proof but 54,000 in the report. Similarly, there is a slight discrepancy in the projected flow between the docks and J29. Clarity required please. c) It would be useful to have a comparable table setting out the 2022 flows for the do March 2017. Page 2. Welsh Government m4 corridor around newport Proof of Evidence Engineering POE Elucidations minimum situation on the existing M4 West of J23A, that is traffic flow ranges compared to predicted traffic.

5 Evidence Table 3: Response to point a): The forecast Do Something opening year 2022 two way AADT on the proposed new motorway between junctions 23 and 23A is 54,000. The figures are quoted on Figure of the Revised Traffic Forecast Report (Doc. ) where the label is closer to the proposed new Glan Llyn Junction. The figures 15,400 E/B and 20,300 W/B (Totalling 35,700 two way AADT) are the Do Something flows for the proposed new dual two lane trunk road link connecting to the reclassified M4 to the west of the west bound free flow link from the M4. These figures therefore include traffic travelling from the M4 to the reclassified M4 as well as traffic travelling from the M48 to the reclassified M4.

6 Refer to the extract from Figure is included below for clarity as new Figure 14 to my evidence: Forecast 2022 Traffic on the Dual two lane Trunk Road Link Forecast 2022 Traffic on the M48. Forecast 2022 Traffic on the proposed new motorway between Glan Llyn Junction and J23 with the M48. Figure 14 Extract of Figure from Revised Traffic Forecasting Report (Doc. ). March 2017. Page 3. Welsh Government m4 corridor around newport Proof of Evidence Engineering POE Elucidations Evidence Table 3: Response to point b): There is an error in the data in Table 3 which I have identified in my list of errata for my evidence (WG.

7 The Core Scenario Forecast 2022 AADT figures between J23- Glan Llyn and Docks-J29 should be transposed. A corrected table is given below: Carriageway Opening Year AADT flow Core Scenario Forecast 2022 AADT All Standard ranges from TA 46/97 D3M. Minimum Maximum J23 Glan Glan Llyn - Docks J29. Llyn Docks D2M up to 41,000. D3M 25,000 67,000 54,000 54,500 52,200. D4M 52,000 90,000. Revised Evidence Table 3 Proposed New Motorway Traffic Flow and Cross Section Evidence Table 3: Response to point c): Additional Table 3a below provides summary of the Do-Minimum forecast traffic flows along the existing M4 north of newport , with figures taken from Figure of the December 2016 Revised Traffic Forecasting Report (Doc.

8 , compared with the opening year AADT flow ranges from TA 46/97. Section of Existing Opening Year AADT flow 2022 Do Minimum existing M4 carriageway ranges from TA 46/97 Forecast two way 1. configuration Minimum Maximum AADT. J29-J28 D3M 25,000 67,000 118,200. J28-J27 D3M 25,000 67,000 111,200. J27-J26 D3M 25,000 67,000 112,900. J26-J25a D2M up to 41,000 76,300. J25a-J25 D2M up to 41,000 98,500. J25-J24 D3M 25,000 67,000 106,900. J24-J23a D3M 25,000 67,000 89,200. Additional Evidence Table 3a Do Minimum Traffic Flow and Cross Section for the Existing M4 North of newport . Evidence para : QUESTION : Do any of these reduced verge and central reservation widths compromise forward SSSD for the design 1.

9 Note that the existing M4 cross sections do not match exactly the D3M and D2M. requirements of TD 27/05 Figure 4-1a. March 2017. Page 4. Welsh Government m4 corridor around newport Proof of Evidence Engineering POE Elucidations speed, for example southwest of Duffryn and east of the proposed viaduct? Evidence para : Response: There are no stopping sight distance (SSD) departures from standards which are directly related to the reduction of the central reservation (CR) width nor the reduced carriageway width over the River Usk Crossing. There are seventeen permitted relaxations to SSD including those at Duffryn and east of the River Usk, plus two more on the River Usk Crossing and thirteen around Magor.

10 There are a total of eight departures from standards relating to SSD, although none of these are attributable directly and only to the reduction in widths of CR and verge. These are located one at Castleton Interchange, one at Docksway Junction and six around Magor Junctions 23 and 23A. Evidence para : QUESTION : There is no mention of the effect that the viaduct would have on shipping bound for the quay sides along the River Usk upstream of the viaduct. As I understand it, this is theoretically is an area within the Port of newport . Evidence para : Response: As shown on Amendment Scheme Order Schedule 3 (Doc. ) and Figure 6 in my evidence, the crossing of the River Usk would provide for of clearance between Mean High Water Springs tide level of + and the soffit of the bridge.