PUBLIC INQUIRY QUESTION

Transcription

1 M4 Corridor around Newport PUBLIC INQUIRY QUESTION REFERENCE NO. : PIQ/164 RAISED BY: The Inspector DATE: 26/02/2018 RESPONDED BY: Matthew Jones DATE: 20/03/2018 SUBJECT: List of questions from the Inspectors Please find below a response to a list of questions submitted by the Inspectors on 26 th February Question No toll scenario is the extra 21% traffic on M4 in 2022 all additional ie on top of growth? (4.87) Lighthouse Lane or Road? (4.93) the now proposed clearances over docks and Usk are m and m? to come with Scheme/Orders? Where is updated ID 008 Have the incident reports on M4 press cuttings dried up? Progress on a word document for Schemes and Orders and Commitments requested by WG Is circular 14/2004 an inquiry document? re Mr Glover/Marshalls Mono/legal point Are TANs 15 and TAN 18 inquiry docs? Response Yes it is. 21% is the additional traffic as a result of going from a half toll to no toll and is in addition to background growth. The growth as a result of moving from full toll to no toll is 35%. The precise figures are set out in my latest rebuttal of Cycling UK s evidence (para. 3) and in the tables which I distributed on 7 th March. Road The proposed clearances over the Junction Cut within Newport Docks, and the River Usk, are 26.2metres (from Design Water Level) and metres (from Mean High Water Spring Level) respectively. We believe this is covered by PIQ159 This is an ongoing process an update will be submitted to the Inquiry Word version provided to the Program Officer ID 203 Tan 15 Doc Tan 18 Doc 6.1.2

2 What stage are we at re WELTAG17 and the joint Minster / Commissioner statement will JD cover that? Yes, this was addressed in the Sustainable Development update by JD, which was presented to the Inquiry on 15 March. Need PI ref for Weltag17 Doc Were 2017 otter surveys Submitted under ID 214 done? When Mr Whittaker reads In both cases of moving from a full toll to a half toll and from in his toll traffic evidence it a half toll to a no toll reduces the generalised cost of travel might be useful for across the crossings, and in the case of the latter situation objectors if he explains removes delay at the toll booths. As a result the major outcome where the 20% toll free leads to some reassignment and a redistribution of trips. In the traffic comes from A465, latter respect, some trips which were wholly carried out in A449 through redistributing Wales and England now change one of their trip ends to because of cost savings etc England I also want his advice re the A48M it is loaded in the am peak but is that because of the through traffic to Cardiff from M4 or the junction hoppers between Cardiff connections out, across, in?. When Mr Bussell delivers his evidence would he tell the Inquiry what the basis is for claiming the user benefits now said to be 1,823m. I am unsure whether this figure takes any account of the factual delay to free flow caused by accidents and non pias? (That is apart from the cost of accidents themselvesstandard COBA default rate). The incident rate has 1 serious delay every 4.5 days throughout the Inquiry period between J23 J29. So I want to know: What constitutes the make up of benefits? Is there any allowance for any delay to free flow from accidents occurring? If so, does the programme accept The A48M is very close to capacity as a result of both through traffic and junction hoppers and the conflicts between the two. The important point is that there is a marginal increase in levels of congestion in the half toll situation and in the no toll a reduction in congestion due to redistribution effects. 1. The Present Value Benefits of the Scheme (as applied to calculate the Initial BCR for the Scheme) are estimated to be 1.8bn as set out in the December 2017 Economic Appraisal Report Supplement No. 3. Transport User Benefits Assessment 2. The transport impacts of the Scheme relate primarily to changes in journey times and vehicle operating costs which are calculated using the TUBA (Transport User Benefits Assessment) programme. The benefits are calculated directly from outputs from the M4CaN Transport Model. The model simulates typical operational conditions on the highway network in terms of average flows and speeds on a normal day of operation. The model does not reflect those occasions when a major incident may have occurred which results in severe reduction in network performance. Accident Impacts 3. Separate to the user benefits assessment, the economic appraisal includes an assessment of accident impacts using COBA LT software. This assessment compares the economic cost of accidents across the network under the do minimum and do something scenarios. Crucially the COBA LT accident impact assessment does not capture the impact of accidents on journey times and network delays. It captures the financial cost of accidents (material damage, police costs, insurance administration and legal costs) as well as the impact on casualties (pain, grief and suffering, lost economic

3 standard accident rates for motorways? Given that there is evidently a high proportion of nonpia incidents, has any account been taken of that fact in assessing the benefits of relieving the existing road? output and medical and healthcare costs). It should also be noted that the COBA LT accident impact assessment only considers the costs of Personal Injury Accidents (PIA). 4. Undertaking the COBA LT assessment requires assumptions on average accident rates. For the existing M4, employed accident rates are based on observed accident rates derived from data collected over the most recently available five year period. In the Do Something scenario, accident rates are assumed to remain constant on the existing M4, though there may be some reduction in accident rates as a result of safety improvements resulting from the reclassification of the existing M4. 5. For the proposed new section of motorway, accident rates are based on average rates for a 3 lane motorway. In reality, it is expected that a new motorway, designed to modern standards, would deliver better safety performance compared with the motorway network on average. However, in the absence of accident rates specifically relating to modern motorways it is not possible to reflect this in the analysis. Benefits Not Captured in the Economic Appraisal 6. Because of this approach, there are two main impacts of the Scheme which are not captured by the economic appraisal. 7. The appraisal does not include the value of improved journey time reliability. In practice, users do not only place a value on the time they spend in transit, they also value the reliability of journeys. Where journey times are highly variable and difficult to predict this imposes costs on users who may suffer disruption to their journey or have to allow extra time for their journey to account for poor reliability. The Scheme, by providing increased capacity and improved safety, will improve the reliability of journeys. 8. Secondly, the appraisal does not capture the benefit that the Scheme will deliver in terms of the frequency and impact of major incidents on journey times. By providing an alternative strategic route through Newport the impact of a major traffic incidents on delays would be considerably reduced. Furthermore, the new motorway would deliver better safety performance than the existing route and thus the frequency of major accidents on the M4 would be reduced. 9. The exclusion of these impacts means that the transport benefits of the Scheme included in the Initial BCR are underestimated. It should also be borne in mind that the quantified wider economic benefits (Wider Impacts) of the Scheme are estimated based on improvements in accessibility based on the average costs of travel derived from the model. Should the costs

4 of poor journey time reliability also be factored into these calculations it would result in the results being revised upwards. Reliability Benefits 10. There is good evidence that road improvement projects do improve journey time reliability. The Department for Transport s Post Opening Project Evaluation (POPE) found that 10 of the 13 schemes it considered (a mixture of bypass and widening schemes) showed a clear improvement in journey time reliability post opening. 11. Evidence suggests that the benefits of improving journey time reliability can be significant. Research in this area has focussed on identifying the value to users of reducing the variability of travel times as measured by the standard deviation of journey times. The reliability ratio expresses the value of a reduction in the standard deviation of journey times as a ratio to the value of a reduction in average journey times. Estimates vary substantially, although the most recent evidence suggests that the reliability ratio is 0.4. This means that, if a 10 minute journey time saving has a value of 1.00, a 10 minute reduction in the standard deviation of journey times would have a value of In practice, applying these values to Scheme appraisal is challenging. Whilst it is possible to demonstrate the existing journey times on the M4CaN are highly variable, it is more difficult to measure with accuracy how this will change in the future. At present, whilst reliability benefits form part of WebTAG guidance, there is no framework within the guidance for the assessment of reliability benefits where a new motorway link is being provided. 13. It is difficult to draw firm conclusions from the literature because of the limited number of occasions where reliability benefits have been included in appraisal. However, a brief review suggests that reliability benefits can up as much as 15% of average travel time savings It would be reasonable to suggest that the M4CaN would deliver a relatively high level of reliability benefits because of the large increase in capacity that it delivers (as compared with on line widening schemes for example) and the increase in resilience inherent in the design both of the new road and the improvements in resilience of the existing road e.g. greater and more consistent provision of hard shoulders/hard strips. 15. The user operational benefits and maintenance impact benefits total 1,828 million (WG Table 2). On the basis that reliability benefits could be 15% of user benefits the reliability benefits would be assessed at 1 For example, M5 Junction 27 to 30 Widening Scheme (DfT Post Opening Project Evaluation Report)

5 274 million. Quantifiable wider economic benefits total 628 million (WG table 3). As stated earlier if there are reliability benefits distinct from journey time savings then these would also impact upon agglomeration effects and the other Wider Impacts and 15% of this figure is 94 million. Accordingly, reliability benefits could total 368 million. 16. Where they are assessed, reliability benefits are included in the Adjusted BCR. Adding 368m to the Adjusted Present Value Benefit of 2,458 (WG Table 3) gives a revised total of 2,826m. By including reliability benefits, the Adjusted BCR for the Scheme would increase from 2.29 to As I have said earlier it is difficult to draw firm conclusions from the literature as to the quantification of the undoubted reliability benefits which the Scheme would bring. The BCR figures cited about should therefore be treated as upper bound figures insofar as reliability benefits are concerned. As I set out in the next section, however, incidents impose additional journey time costs which are not captured by the model and which are over and above these reliability benefits. Network Resilience and the Impact of Traffic Incidents 18. Reliability benefits relate specifically to the unpredictability of journey times and not the delays themselves. Therefore the impacts of traffic incidents on journey times and cost and are therefore additional to the impacts on reliability. 19. Modelling the benefits of improved resilience in a systematic way is difficult and beyond the capability of a transport model built to simulate normal operating conditions. In practice, every incident that occurs on the M4 is different in respect of its location, impact and duration. The type and nature of traffic incidents on the existing M4 is highly variable. Some incidents will have a relatively slight impact on traffic conditions whilst other incidents require the closure of the motorway and result in severe delays and disruption lasting several hours. Reliable data does not exist which records the impact of incidents on traffic on the M4 and the knock on effects on the wider network. 20. The effect of the Scheme is also complex because it will both reduce traffic flows and the frequency of incidents on the existing route whilst also providing a bypass. Even if we were able to predict where and when incidents will occur, transport models assume drivers have perfect knowledge and are not designed to replicate driver behaviour in response to a traffic incident. 21. For these reasons it is not possible to provide quantified estimates of the impact of traffic incidents on the existing M4 and nor is it possible to provide estimates of the benefits delivered by the Scheme in this respect.

6 From previous evidence submitted by Mr Whittaker earlier I appreciate the complexity of calculating the economic dis benefit of traffic diversions in the event of an incident but I wonder if there is a simple equation that could be drawn up to reflect reality here. Given the frequency of traffic incidents (even with an incident occurring every 4.5 days) it would be reasonable to assume that by capturing day to day congestion the Transport Model accounts for a large majority of benefits that would occur in practice. That said, major incidents on the M4 around Newport can have a highly disruptive effect on traffic and therefore it is also reasonable to assume that the economic costs are not insubstantial. 22. In respect of the economic impact of major incidents it should also be considered that the costs of the disruption caused to business activity are likely to be in excess of the costs suggested by standard values of travel time savings. From a wider economic perspective, although more difficult to evidence, it may be the case that severe disruption has a disproportionately negative effect on people s perceptions of South and West Wales as a place to visit or invest. Conclusion 23. It is not practical to quantify the costs of actual delays caused by incidents. Viewed as a quantification purely of reliability benefits, the figure of 368m given in paragraph 16 (and the revised adjusted BCR of 2.63) should be regarded as an upper bound figure. However, this does not take into account an important set of benefits which would be conferred by the Scheme in respect of lessening the impact of traffic incidents. Having regard to these countervailing influences, in my opinion the revised BCR represent a fair estimation of the BCR of the Scheme having regard to all aspects relating to reliability and resilience. I reiterate that as the calculation is not one based on a recognised and prescribed methodology then the degree of uncertainty is greater than it is in respect of the BCR calculations set out in my proofs of evidence and the Economic Appraisal Reports. There is a limit to what could be practically achieved here. Incidents are random events, that can arise during different times of the day, different levels of severity which may be partial or total closures, different durations etc. As a result it would be very difficult to develop an equation that fits all situations. One example of the potential costs of delay, is contained in the Annex to my original proof of evidence WG Mr Bussell deals with this point in answer to the question addressed to him.

7 It would be beneficial for objectors to see a suitable PIQ response before they reappear if Mr Kells is then too rushed next week I will allow a fresh submission by him on any PIQ you submit if need be. Noted