I think that you may still be missing something

In So that’s why you ignored it (posted 11 May 2012) I observed that, whilst the noise generated by a train pass-by would be exactly the same by day and by night, it was a peculiarity of the equivalent continuous sound level calculation that, at any given location, L_{Aeq, day} will exceed L_Aeq,night by about 5 dB(A). To put this another way, by day the peak level of a train pass-by will be around 14 dB(A) higher than the equivalent continuous sound level (see note below), but at night this difference will be (14+5), or 19 dB(A), higher.

This is another good illustration of why the equivalent continuous sound level does not give a complete picture of the noise nuisance level, but it also reinforces the argument that I made in my blog A rude awakening (posted 11 Dec 2011) that further consideration needs to be given to the possible sleep disturbance effects of peak noise levels at night.

As an illustration of this point, consider a bedroom where the façade of the building where the bedroom is located is experiencing an incident noise level from HS2 of 40 dB(A) L_Aeq,night, which is, of course, the NNG. The peak noise level incident on that façade will be (40+19), or 59 dB(A). The Night Noise Guidelines for Europe (here) discusses, in paragraph 1.3.4.4 on pages 9 and 10, how much the fabric of the building will reduce the noise level outside to arrive at a noise level actually inside the bedroom; it calls this noise reduction the “insulation value”.

The same paragraph in the Night Noise Guidelines for Europe gives typical values for the insulation value of 15 dB with windows open and 30 dB with windows closed, and opts for a year-round average figure of 21 dB. So a noise level just on the NNG outside will give a peak level in the bedroom of 44 dB(A) (59 dB(A) -15 dB(A)) with windows open and 38 dB(A) (59 dB(A) – 21 dB(A)) as a year-round average.

In A rude awakening I explained that WHO night time noise guidance prior to the publication of the Night Noise Guidelines for Europe recommended both equivalent continuous and peak noise level limits. The recommended maximum peak noise level within the bedroom then was 45 dB(A); even with windows open the NNG equivalent continuous threshold will trigger before this peak is exceeded.

As I also explained in A rude awakening, the Night Noise Guidelines for Europe adopts the equivalent continuous sound level as the sole metric for its night noise recommendations; it does this to “be consistent with existing practices in the legislation”. However, this same document also acknowledges the position taken by the WHO previously that the maximum sound level per noise event is also relevant to considerations of sleep disturbance. It also concludes that the earlier recommended maximum peak level may have been set too low, as “thresholds are now known to be lower than L_Amax of 45 dB for a number of effects” (page xviii of Night Noise Guidelines for Europe). Data presented in Table 1 on page xiii indicates that physiological effects may be observed at peak noise levels as low as 32 dB L_Amax,inside.

So even with all windows closed the peak level in the bedroom caused by a sound level just at NNG level outside will exceed, by an appreciable margin, levels which the WHO has acknowledged may cause physiological effects.

So even though the adoption by HS2 Ltd of the WHO NNG is very welcome, there is still cause for concern that the high peak to equivalent continuous ratio exhibited by HS2 noise, particularly at night, may mean that health risks caused by peak noise in the bedroom at lower levels will still be overlooked. My suggestion is that HS2 Ltd should commission a thorough review of this matter.

Note: The origin of this 14 dB(A) may be found in my blog I only just noticed that (posted 25 Apr 2012).

So that’s why you ignored it

In A step in the right direction (posted 7 May 2012) I promised that I would look at the impact that adopting the World Heath Organisation (WHO) night noise guideline (NNG) might have on the estimated count of the number of properties affected by HS2 noise; so how might we do this?

Well the first thing to take into account is that, although HS2 trains operating at night will be no quieter than those running during the day, the “equivalent continuous sound level” method employed by HS2 Ltd to calculate noise will yield a lower sound level for the eight night hours between 23:00 and 07:00 than for the sixteen day hours between 07:00 and 23:00. This is because, whilst the contribution to the total noise power over the time period used to calculate the equivalent continuous sound level is the same for each train pass-by (day or night), there will simply be fewer train movements at night.

In my blog Silent night? (posted 3 Dec 2011) I showed how the difference in the day and night time equivalent continuous sound levels could be calculated based upon the train movement data in Table 1 on page 45 of Appendix 5.4 to the Appraisal of Sustainability (here). In that blog I came up with the answer that the night equivalent continuous sound level would be about 5 dB(A) lower than the daytime equivalent.

Now there are two caveats that I should apply to this result. The first is that train timetabling for HS2 is, as might be expected at this stage of the project, a bit of a wet finger in the air activity, and so the data in the AoS table is not definitive. The second is that the goal posts for the daytime equivalent continuous sound level have been moved slightly; the period employed for the AoS was 06:00 to 24:00 and it is now proposed for the EIA that the period 07:00 to 23:00 is used to be consistent with the adoption of a 23:00 to 07:00 night-time period. Both of these caveats can affect the calculation, but I would expect any differences to be small and am confident that we can disregard them for the purposes of this blog.

This calculation allows us to draw a significant inference. At a location where the night noise is just at the NNG threshold of 40 dB(A), the equivalent daytime noise level will be (40+5) or 45 dB(A). Now this is a significant 5 dB(A) below the “grey dot” daytime threshold of 50 dB(A) that was used to calculate the “estimated number of dwellings potentially impacted by operational noise” given in Table 3 and Table 4 on pages 51 and 52 of Appendix 5.4 of the AoS; this estimate is approximately 24,300 dwellings without the Y extensions and 33,600 with the Y extensions (both without additional mitigation). So I think that we can expect this count of dwellings to go up somewhat, due to locations that exceed the NNG but did not exceed the day threshold employed for the AoS.

It is difficult to estimate just how much the count of affected dwellings will increase due to the inclusion of those above the night-time threshold only; we will have to wait for HS2 Ltd to do the detailed calculations. We can get some idea from the observation made by Southdowns Environmental Consultants Ltd in paragraph 2.3.2 in Appendix 18 to the 51m alliance response to the public consultation (here) that a 1.25 dB(A) difference (due to inclusion of the Y extension traffic) is all that was responsible for the increase in the count of affected dwellings (without mitigation) from approximately 24,300 to approximately 33,600 (around a 40% enlargement).

Now we have to be careful about drawing a direct comparison, because (as I stated in A step in the right direction) the night threshold will probably have most impact in rural areas where property densities are low. There have also been changes to the route design since the AoS was issued. However, it looks likely that the tally of affected properties could go up significantly (perhaps even doubling) when night noise impacts are taken into account.

I think that we can see now why HS2 Ltd preferred to ignore night noise in the AoS.

A step in the right direction

I mentioned in my blog Here comes more work (posted 3 May 2012) that I had found a surprise in the draft of HS2 London to West Midlands EIA Scope and Methodology Report (here); after trying to convince us in the Appraisal of Sustainability (AoS) that night noise from HS2 wasn’t worth bothering about, HS2 Ltd now appears to appreciate that it might be a problem.

In my blog Nessun dorma(posted 7 Dec 2011), I pointed out that the AoS had completely ignored the recommendations of the World Health Organisation (WHO) document Night Noise Guidelines for Europe (here). Well it now appears that the acousticians working for HS2 Ltd have found a copy, dusted it off and realised that they ought to pay attention to it.

In Nessun dorma I explained that the WHO had recommended a night-time noise threshold, identified as the night noise guideline (NNG), together with a higher-level interim target (IT) for “situations where the achievement of NNG is not feasible in the short run”. It would appear that HS2 Ltd has adopted the NNG, which is specified as 40 dB(A) equivalent continuous sound level over the eight night hours, as the threshold for night-time noise in HS2 London to West Midlands EIA Scope and Methodology Report.

The way of applying this threshold is a little convoluted. It is set out in paragraphs 13.3.24 and 13.3.25 on page 119 of HS2 London to West Midlands EIA Scope and Methodology Report. In order to record a “noise impact” at a receptor the forecast HS2 noise must cause “a change in the equivalent continuous sound level between 23:00 and 07:00 of 3 dB or greater” and that increased equivalent continuous sound level must exceed the NNG level of 40 dB(A).

Now it shames me to admit it, but over the last couple of years I’ve learnt a healthy scepticism when dealing with HS2 Ltd. However, I have thought about this proposal carefully and can’t find the catch; maybe someone cleverer than me can spot one. It is basically the same way the AoS used the daytime 50 dB(A) threshold that marked the bottom of the “grey dot” band. Whilst I have a problem with this daytime threshold being inconsistent with the assumption that existing noise levels in tranquil areas is 45 dB(A) (refer to my blog That’s a bit of an understatement, which was posted 5 Nov 2011), I have no quarrel, I think, with the application of the “3 dB change” criterion.

By the way, paragraph 13.3.25 also confirms that this 50 dB(A) threshold, together with the 3 dB change requirement, has been retained as the daytime threshold for the HS2 London to West Midlands EIA Scope and Methodology Report.

But I digress; getting back to this new night-time threshold, because of the “3 dB increase criterion” the existing night noise equivalent continuous sound level must not exceed 37 dB(A) for the 40 dB(A) threshold to apply. This is because for every dB that the existing night noise equivalent continuous sound level exceeds 37 dB(A), the 40 dB(A) threshold will increase by 1 dB(A). So if the existing noise level is 40 dB(A), the night noise will not be recorded as a “noise impact” unless it exceeds 43 dB(A).

What this calculation process means is that the adoption of the WHO NNG for the EIA process will have most impact in areas where the nights are relatively tranquil at present; presumably this will be predominantly rural areas where there are no existing transport corridors. It is also more likely that the threshold will be exceeded in track sections where the trains are running at maximum speed. Since this description fits the vast majority of the route from the Chilterns up to Warwickshire and even the rural parts of the West Midlands, the adoption of this new threshold may influence the number of “noise impacts” that HS2 clocks up; or put more simply it may increase the count of properties that are affected by noise.

In the next blog I shall try and get some idea of how large this increase might be.

Here comes more work

In a postscript to I only just noticed that (posted 25 April 2012) I mentioned that HS2 Ltd has published in draft a new tome for our delectation, succinctly entitled HS2 London to West Midlands EIA Scope and Methodology Report. If you are a sad case like me, and get a kick out of reading such things, the delight of delving into this almost two-hundred page work is only a mouse click away.

This is an important publication as it will, as it says in its title, set the scope of the environmental impact assessment (EIA) work and the methodology to be employed; we can expect that it will become the “bible” for the EIA activities and discussions over the next year or so. So it is right that HS2 Ltd has issued its document in draft for consultation. However, anyone who has been foolish enough to click the link above and actually read any of it will, I’m sure, agree with me that it pretty specialist stuff. So HS2 Ltd does not envisage a public consultation like the one last summer and has taken the step of publishing a list of the bodies that it considers as “formal consultees” in Annex A, which forms chapter 20 of the report (on pages 175-177).

This listing is introduced by the following paragraph:

“Comment will be sought from the following list of formal consultees on the content of the Scope and Methodology Report. Consultees are not limited to this list and responses received from others will be taken into account where they are relevant to the Scope and Methodology consultation.”

So if you want to respond to the consultation, as an individual or on behalf of an action group for example, you can and, if HS2 Ltd considers your observations “relevant”, they will be “taken into account”. So if you want to avoid your submission being binned, just make sure that you don’t make irrelevant comments. Better still, get a “formal consultee” to make your comments on your behalf.

The list of the bodies that HS2 Ltd considers competent to respond is interesting. The usual suspects are included; including a selection of government agencies, Network Rail, Transport forLondon and the Health and Safety Executive. Every local authority affected by the route is also listed, including the Greater London Authority, Birmingham City Council, county councils, borough councils and district councils.

The list also includes seventy-three parish councils, plus a further nine added by an erratum (here). It is strange to me that HS2 Ltd sees fit to include all of these parish councils, which on the whole are unlikely to be able to resource much in the way of specialist environmental knowledge, but excludes any environmental charities (such as the wildlife trusts), action groups or, would you believe it, the Chilterns Conservation Board.

We all have until 12:00 hrs on 30 May 2012 to respond (the consultation officially started on 4 April 2012).

Like many others, I will be working my way through the document during the time allowed to see if I have any comments to make that HS2 Ltd may deem to be relevant. As you might expect if you have read many of my blogs, the first section that I looked at was on airborne sound (section 13.3 on pages 114 to 122). There I found a surprise, which I will tell you about in my next blog.

There’s more than one way to skin a rabbit

This is the final blog that I propose to devote to the analysis by Dialogue by Design of the responses to Question 6 of the public consultation on HS2, which asked respondents whether they wanted to comment on the Appraisal of Sustainability (AoS).

In a paragraphs 6.3.60 to 6.3.62 on pages 130 and 131 of High Speed Rail: Investing in Britain’s Future Consultation Summary Report (here) we are advised that “a number of respondents outline their opinions about the possible alternatives to a high speed rail network in their comments about the AoS”.

More specifically we are told:

“There are 1,297 respondents who believe that the proposed high speed rail network is not the most sustainable option, while 934 respondents express the opinion that alternatives have not been given adequate consideration.”

And the Department for Transport need not feel short of advice about what these alternatives might be:

“Some respondents go on to indicate which other approaches or schemes they think would be more sustainable than the proposed national high speed rail network. The most frequent suggestion is to invest in the existing rail infrastructure; respondents think this would be a more sustainable means of creating additional capacity than building new infrastructure. Others recommend investing in IT capabilities and focusing on reducing the need to travel by encouraging more people to live and work locally. There are 597 comments mentioning electric vehicles and green technology, in some cases suggesting that some or all of the money proposed for a high speed rail network should be used to develop and roll out these technologies.”

HS2 Ltd doesn’t address these issues directly in its document Review of HS2 London to West Midlands Appraisal of Sustainability (here). The only relevant comment that HS2 Ltd makes appears in paragraph 3.1.2 on page 10, where the requirements of the Strategic Environmental Assessment Directive (SEA) are referred to. In this paragraph HS2 Ltd makes the claim that “the AoS was intended to be compliant with the principles of SEA”. It also offers the view that “as part of [the SEA] assessment, consideration must be given to reasonable alternatives that are available”.

Having specifically made this last point, it is strange that HS2 Ltd does not realise the obvious contradiction in its position. An important purpose of the SEA, as described in A Practical Guide to the Strategic Environmental Assessment Directive (here) is to compare the environmental impacts of the reasonable alternatives. Since there are clearly reasonable alternatives that the AoS has not considered, such as “to invest in the existing rail infrastructure” as suggested by respondents to the consultation, it appears that the AoS fails to be compliant with SEA in at least this one important aspect.

This did not escape the respondents to the public consultation, as Dialogue by Design reports in paragraph 6.3.62 on page 131 of High Speed Rail: Investing in Britain’s Future Consultation Summary Report:

“There are comments from organisations as well as members of the public suggesting the AoS should set out how the sustainability of the proposal compares to alternatives such as not investing in high speed rail or upgrading the wider transport network, or establishing specific improvements.”

One of the organisations that commented on this issue was the 51m alliance of local authorities. It sets out its complaint very clearly in paragraph 13.15 on page 13-5 of Appendix 13 to its consultation response document (here), as follows:

“The AoS has only been carried out for one rail option, rather than as a comparative assessment of different options. The process by which the proposed route has been defined has not been carried out in an open and transparent way. By not undertaking a comparative high level assessment of the alternatives to HS2 and the proposed route, it is not possible to determine whether the scheme is the most sustainable way to meet the purported ‘need’. The assessment highlights a range of negatives with the proposed routes and it is therefore essential to carry out a more rigorous assessment to determine whether alternatives are more sustainable.”

However, HS2 Ltd will have nothing to do with this and the other complaints about the methodology used for and contents of the AoS. It sets out its overall response to the consultation responses to Question 6 in chapter 10 on page 32 of Review of HS2 London to West Midlands Appraisal of Sustainability. Whilst conceding that “a number of areas would need to be addressed further in the next stage, when an EIA would be undertaken”, its conclusion about the suitability of the AoS is predictable:

“For the current stage of the project, we conclude that our approach to examining the impacts on the environment and sustainability through the AoS is appropriate.”

I only just noticed that

As I promised in May I suggest a better option? (posted 21 Apr 2012), in this blog I will consider whether the representation of the noise nuisance caused by HS2 solely by an equivalent continuous noise level parameter gives a true representation of the impact of that noise nuisance.

I have already commented upon this question in earlier blogs. In Taking a longer-term view (posted 22 Jun 2011) I quoted the view of the World Health Organisation (WHO) that “when there are distinct events to the noise such as with aircraft or railway noise, measures of the individual events should be obtained (using, for example, L_Amax or SEL), in addition to L_Aeq,T measurements”. In other words the equivalent continuous noise level parameter should be used alongside another parameter that reflects the magnitude of individual noise events.

I have also noted that the preference for the equivalent continuous noise level in Europe is not necessarily shared in other parts of the World. In my blog That’s much louder than the average (posted 29 Nov 2011) I mentioned that the Japanese, who are no slouches when it comes to high speed railways and dealing with the noise there from, use peak noise to specify noise limits.

The EU Environmental Noise Directive 2002/49/EC (here) offers no obstacle to the use of a parameter reflecting the contribution of individual noise events alongside the specified equivalent continuous noise level parameters. Paragraph 3 of Annex I on page L189/19 permits “supplementary noise indicators” to be used, and some at least of the examples of where this would be appropriate that are given on that page seem to apply to HS2.

In my view, the characteristics of the noise pollution caused by HS2 mean that the noise nuisance caused will never be adequately expressed by an equivalent continuous noise level parameter alone and it would be totally inexcusable for HS2 Ltd to ignore WHO advice on this matter. In order to illustrate why I think this, I will use the remainder of this blog to describe a simple example of where the use of an equivalent continuous noise level parameter fails to do the job adequately.

In That’s a bit of an understatement (posted 5 Nov 2011) I explained that, in setting the lower end of the grey dot rating for properties, the Appraisal of Sustainability (AoS) was effectively assuming that the ambient noise level before the noise from HS2 was introduced was 47 dB L_Aeq,18hr. The AoS assumes that existing rail noise levels at such a location are low, or there is no rail traffic. I think that it is safe to assume that, at such locations, there is no other predominant source of noise either. So what will we hear at such locations before HS2 imposes itself on the environment? The answer is probably typical rural sounds such as birdsong, livestock in the fields, the wind in the trees and, possibly, the distant rumble of traffic.

I am quite prepared to accept that L_Aeq,18hr will be a reasonably accurate representation of the ambient, since I would not expect any individual noise events to be markedly above the “average level” defined by this parameter.

To this reasonably tranquil scene we must add HS2 noise; for the bottom threshold of the grey dot classification this will be at a level of 50 dB L_Aeq,18hr. The 3dB margin above the ambient has been taken as the level at which the new noise becomes just noticeable. This is where the methodology falls down, because the HS2 noise does not have the same characteristics as the ambient noise. The HS2 noise will be characterised by a series of separate noise events, where the level of these events will be significantly above the “average” defined by the parameter L_Aeq,18hr.

In paragraph 5.4.7 on page 16 of Appendix 18 to the 51m consultation response (here), Southdowns Environmental Consultants Ltd reveals just how much these single events will be above the L_Aeq,18hr level. The answer, which is based on information obtained from HS2 Ltd under a Freedom of Information request, is 14 dB. So that means that each single HS2 noise event will be a massive 17 dB above the “average” ambient noise level.

Now I don’t know about you, but my ears don’t work on 18 hour averages; they detect noise instantaneously. My ears won’t perceive a spike that is 17 dB above the ambient noise level as just noticeable; it will have a severe impact and, remember, that is at the bottom end of the grey dot scale.

So the answer to the second question that I posed in May I suggest a better option?  is also no.

The AoS completely fails to get to grips with this reality of HS2 noise nuisance and this shortcoming must be addressed by HS2 Ltd.

PS: In its recently published document HS2 London to West Midlands EIA Scope and Methodology Report (here) HS2 Ltd lists the train pass-by peak noise parameter as one of the metrics that it will employ to assess noise nuisance levels for the Environmental Impact Assessment. However, this apparent change in policy since the AoS was written will have, it appears, absolutely no effect in view of the threshold value for this parameter that HS2 Ltd has specified. At 85 dB L_pAF,max façade (82 dB L_pAF,max free field) this threshold is way, way above the level at which annoyance will start. What HS2 Ltd has done totally misses the point of the WHO recommendation, which is to employ the peak noise level as an alternative means to the equivalent continuous sound level to make an assessment of the degree of the annoyance caused.

May I suggest a better option?

As I said in my blog Going over some old ground (posted 17 Apr 2012), I intend to devote this current blog and the next to reviewing the issue of selecting appropriate parameters to express the noise impact of HS2 meaningfully. Some of this will be a restatement of what I said in my blogs Taking a longer-term view (posted 22 Jun 2011) and That’s much louder than the average (posted 29 Nov 2011), but also some is new.

I believe that there are two issues here. The first is whether the parameter selected by HS2 Ltd, L_Aeq,18hr, is the most appropriate way of representing the equivalent continuous noise level for HS2. The second is whether the representation of the noise nuisance caused by HS2 solely by an equivalent continuous noise level parameter gives a true representation of the impact of that noise nuisance.

HS2 Ltd is right to claim, as I reported in Going over some old ground, that “in the UK and the EU, regulations, standards and policy all adopt [the equivalent continuous noise level] to describe railway noise for both conventional and high speed lines”. However, there is little uniformity between these various authorities as to the precise parameter to be used to express the equivalent continuous noise level.

In the absence of a consensus, it is suggested that HS2 Ltd should pay due regard to the requirements of the EU Environmental Noise Directive 2002/49/EC (here). This Directive employs two equivalent continuous noise level parameters, termed the “noise indicator for overall annoyance”, or L_den, and the “noise indicator for sleep disturbance”, or L_night. The Directive requires that both of these indicators are employed to assess the nuisance level.

For those not familiar with these two parameters I should explain that they are both derived by considering the day of 24 hours being split into three periods: a day period of 12 hours, an evening period of 4 hours and a night period of 8 hours.

This allows L_night to be defined as the equivalent continuous noise level (A-weighted), calculated over the 8 hour night period. If similar calculations are also made for the day period (L_day) and the evening period (L_evening), then L_den (the day, evening, night level) is calculated from the logarithmic composite of the L_day, L_evening and L_night levels but with 5dB(A) being added to the L_evening value and 10dB(A) being added to the L_night value. This boosting of the evening and night values takes account of the increased annoyance that noise pollution causes during these periods.

Now I think that L_den is a pretty neat concept and I can’t understand why it is not used more widely in the UK or why HS2 Ltd is not promoting its use for HS2. I suspect that it may have something to do with the increased dBA levels that result from the application of weighting to the evening and night periods.

So the answer to the first question that I posed early on in this blog, about whether L_Aeq18hr is the most appropriate way of representing the equivalent continuous noise level for HS2, is probably no.

In the next blog I will consider the second question that I posed above.

Going over some old ground

In paragraph 6.3.49 on page 128 of its report High Speed Rail: Investing in Britain’s Future Consultation Summary Report (here) Dialogue by Design tells us that 799 respondents “argue that using averages instead of peak or pass-by noise levels is inappropriate”. Now this is quite a complex technical point and I was amazed to learn that so many people had picked up on it; they couldn’t all have been readers of my blogs.

This indicates to me that HS2 Ltd is making a mistake if it underestimates the intelligence of its critics. The response given in paragraph 7.2.7 on page 27 of Review of HS2 London to West Midlands Appraisal of Sustainability (here) indicates that it might be. Most of this paragraph is spent telling us what the equivalent continuous sound level, L_Aeq, is; I think that the 799 souls who raised this as an issue were probably already familiar with the concept, otherwise I doubt that they would have commented as they did.

We are also told in this paragraph that:

“In the UK and the EU, regulations, standards and policy all adopt this indicator to describe railway noise for both conventional and high speed lines.”

And:

“The L_Aeq is the standard and most proven single indicator for determining noise impact of transport schemes and was therefore appropriate for the appraisal of HS2.”

These two sentences do little more than restate similar claims in section 1.2 on page 39 of Appendix 5.4 to the Appraisal of Sustainability Main Report (here).

Given the track record of HS2 Ltd, this is an entirely expected, but nonetheless disappointing, response. It is just not good enough. HS2 Ltd owes it to all those who will be affected by HS2 noise pollution to carry out a proper review of this issue to determine what are the most appropriate parameters to describe the impact of very high speed train noise accurately. This will be a new source of noise pollution and the reliance on the defence of using established parameters will not wash.

This is a very important issue because sole reliance on the single parameter L_Aeq,18hr to assess noise impacts carries a very great risk that these impacts will be understated and I intend to devote my next two blogs to explaining why I think this.

There are two further noise issues that have been raised in responses to the consultation, but are not mentioned in the Dialogue by Design report and we have to rely upon these being identified in Review of HS2 London to West Midlands Appraisal of Sustainability.

The first of these two issues is the 3 dB reduction in source noise level that has been assumed “based on the anticipated noise control improvements in the next generation of high speed rolling stock”; refer to paragraph 6.3.3 on page 50 in Appendix 5.4 to the Appraisal of Sustainability Main Report. No justification for this claimed noise level improvement was given in the Appraisal of Sustainability (AoS), but this is now provided by HS2 Ltd in its AoS review document (in paragraph 7.2.4 on pages 26 and 27). As I reported in my blog Perhaps you were right all along, perhaps not (posted 25 Nov 2011), the authority for this claimed noise reduction is an EU Commission Decision document and this is confirmed in the latest HS2 Ltd document (but see my PS, below).

In Perhaps you were right all along, perhaps not I gave reasons why the assumption of this 3 dB improvement is by no means a straightforward matter and I welcome the assurance in paragraph 7.2.4 of Review of HS2 London to West Midlands Appraisal of Sustainability that “the train noise level will be revisited and checked for suitability as the input to the more detailed EIA”. I trust that this work will be fully reported to the public in due course.

In this context I also trust that HS2 Ltd will similarly review whether an increase in source noise level should be made to allow for operational degradation in the track roughness, as suggested in my blog It could be a bumpy ride (posted 24 Oct 2011).

The second issue is the effective height of the train noise source compared to the proposed height of noise barriers and the resulting efficiency of the barriers. In Review of HS2 London to West Midlands Appraisal of Sustainability (in paragraph 7.2.5 on page 27) HS2 Ltd characterises this as “noise from the train pantograph”, although there are also other sources of aerodynamic noise high up on the train which may contribute. HS2 Ltd says in this paragraph:

“The pantograph is a consideration in the assessment of the noise impact and the AoS took this into account by making appropriate changes to the relative height of train source and barrier when considering mitigation. While noise from the pantograph does need to be considered, and will be reviewed at the time of the EIA, its significance is often overstated. The wheel-rail interface will remain the most significant part of the noise from the train, even at high speed.”

So we are, rightly, promised that this topic will be reviewed, and we are also told what the outcome of the review will be. Strange sort of review process, isn’t it?

I have already discussed this topic in my blogs A little bit of magic (posted 17 May 2011) and Going over the top (posted 9 Nov 2011), but I plan to research this potentially very important topic further and will report my findings in a future blog.

PS: The EU Commission Decision that allows the 3 dB reduction in source noise to be made is given as 2008/163/EC in footnote 24 on page 27 of Review of HS2 London to West Midlands Appraisal of Sustainability. Believing this to be an error, I queried it with the Department for Transport and have received confirmation that the correct EU Commission Decision is 2008/232/CE; this is the document that I quoted from in my blog Perhaps you were right all along, perhaps not.

Keeping us in the dark

In paragraphs 6.3.48 to 6.3.50 on page 128 of its report High Speed Rail: Investing in Britain’s Future Consultation Summary Report (here) Dialogue by Design presents its analysis of what respondents to the public consultation on HS2 said about noise pollution.

We are told that a “total of 2,945 respondents are generally concerned about the noise a high speed line will generate”. Also 3,046 respondents “express the opinion that either the noise assessment is inadequate, or more information about it needs to be provided”. More specifically, 514 respondents “mention concerns about vibration in particular” and 333 respondents comment upon the sound simulation at the roadshows, “often expressing doubt as to whether it provides a realistic indication of the actual operational noise”.

I must say that I share these doubts. After spending many hours on the research that has been necessary to inform the blogs that I have written on HS2 noise, I still have to answer when asked how bad it will be, “I’m sorry, I just don’t know”. The only thing that I can say, with my hand on my heart, is that I believe that HS2 Ltd is seeking to underestimate the impacts of HS2 noise and overstate the benefits of the proposed mitigation measures.

So does HS2 Ltd have anything new to say to those of us who are worried about noise in Review of HS2 London to West Midlands Appraisal of Sustainability (here)? There is a section on Appraisal of airborne noise (section 7.2 on pages 26 to 28), but this says very little that we have not heard before from HS2 Ltd, and I don’t think that this will do anything to reassure the doubters. There is an acknowledgement, in paragraph 7.2.1, that:

“Noise attracted a significant number of comments in response to the consultation, in particular the predicted noise levels and the prediction methods.”

There is even an assurance, in paragraph 7.2.2, that HS2 Ltd knows that it has a PR problem in this area:

“We are aware of the concern communities that are alongside the proposed route for HS2 have regarding noise.”

So why on earth isn’t HS2 Ltd doing anything to allay those concerns? Why has HS2 Ltd avoided meaningful technical discussions on noise with action group representatives? Why has the information provided on noise impacts on properties been limited to fuzzy maps, calculated using an inappropriate noise model, with fairly meaningless dots on them, rather than proper noise contour maps (refer to Pass me the map, posted 30 Jun 2011)? Why does the grey dot on HS2 Ltd maps cover a range of impacts from slight to very severe (refer to That’s a bit of an understatement, posted 5 Nov 2011)? Why were the noise simulation demonstration booths at the roadshows treated with such scepticism (refer to Have you heard?, posted 12 Jul 2011)?

HS2 Ltd addresses the missing noise contour maps in paragraph 7.2.8 on pages 27 and 28 of Review of HS2 London to West Midlands Appraisal of Sustainability, thus:

“… given the strategic nature of this stage of route design it was not considered appropriate to publish noise contour maps due to the risk of misleading the public on noise levels at specific properties, given that we have not performed detailed baseline noise surveys to verify our predictions of the existing background noise environment.”

In other words, they haven’t really got a clue about what the noise levels will be at any one particular property, which means that the counts of properties affected that were given in the Appraisal of Sustainability (AoS) are probably totally meaningless.

Paragraph 7.2.8 continues:

“If proposals for the route are taken forward, the EIA would undertake more detailed and localised assessment of noise and this could allow for the production of detailed noise analysis and detailed recommendations for future noise mitigation.”

I would jolly well hope that the EIA process will include a proper and detailed prediction of noise impacts at all points along the route, but am worried that “could allow for the production” implies that there is some doubt about this. It would surely be a scandal if HS2 Ltd found itself unable to provide this information to affected householders.

It is good that HS2 Ltd acknowledges that communities are concerned about noise, but it is also time that HS2 Ltd recognised that action groups have more than concerns; they have precise technical questions (here) that HS2 Ltd has, largely, failed to address. We have been promised, on more than one occasion, that HS2 Ltd will organise a technical seminar specifically to address our questions on noise and it is high time that this took place.

There will be more on noise topics raised by the consultation in my next blog.

Supping with the Devil

In my blog Meeting at the Forum (posted 5 Apr 2012) I mentioned the Community Forums that HS2 Ltd has set up to help “build a relationship with local communities”. In this current blog I will give my personal reactions to the Community Forum idea, including some feedback from attending the first meeting of my local forum, which covers the route through the mainly rural area of Warwickshire that lies within the parishes of Offchurch and Cubbington.

Some members of the campaign against HS2 feel that sitting down with HS2 Ltd at this early stage amounts to an admission of defeat in the war against HS2. In their eyes, collaboration undermines the position of those who think that the only satisfactory “mitigation” against the environmental impacts of HS2 is to stop it in its tracks.

I appreciate that supping with the Devil has its dangers, and remain totally opposed to the HS2 project. However, I feel that I would be failing my local community if I were to turn down any opportunity to contribute to measures being agreed that may lessen the impact that HS2, were it to be built, will have on our local environment. I also think that the mitigation that has been proposed so far has indicated that the communities that have got their proposals in early have faired better and that the rest of us are facing a limited window of opportunity in which to negotiate our own improvements and a diminishing pot of money to pay for them. On this basis, I have opted to take part in our local Community Forum.

However, I do not think that the Community Forums will, on their own, be a sufficient mechanism to allow full discussion of local issues and mitigation proposals. A meeting of twenty or more people is hardly the place to discuss problems and proposals in the required detail. With this in mind, I am pleased to see that the HS2 Ltd diagram that I reproduced in Meeting at the Forum shows “ongoing bilaterals” as external to the forum structure. The briefing note confirms this interpretation of the diagram, promising that the “three-part structure” will be “supplemented by bilateral meetings and engagement, particularly in relation to bespoke issues and localised matters”. However, my own action group and our friends in neighbouring Offchurch have jointly been seeking such a bilateral meeting with HS2 Ltd to discuss our local issues, so far with a promise of a meeting but no actual date.

We had our first meeting of the Offchurch and Cubbington Community Forum at the end of March. I was pleased to be introduced to the members of our “geographically-focused development team”; these being HS2 Ltd employees with specialisms such as route engineering and environmental matters, who will work specifically on the area covered by a number of identified community forums, including ours. This should allow a continuity of personal relationships and encourage us all to get to know one another over the coming months.

We all tried hard to be pleasant to one another. I appreciate that it cannot be easy for professional employees of HS2 Ltd to be taken to task on matters by a bunch of amateurs (sorry, I mean representatives of the local community). Likewise, one or two of us local representatives got a trifle hot under the collar when HS2 Ltd staff demonstrated that they hadn’t taken the trouble to get up to speed with local details. However, some of these individuals appeared to be fairly new in their jobs and we should allow time for them to study their briefs. However, this is an excuse that will cut no ice at the second and subsequent meetings.

It was also apparent that HS2 Ltd hasn’t really thought through some important ramifications of the community forum idea, such as public (and press) access to proceedings and keeping the local community informed generally. There were also some administrative matters that were lacking in detail, such as keeping and approving minutes (or notes) of the meetings and how members of the group would communicate with each other in the periods between meetings.

I think that generally the meeting went well and I learnt a number of things which hadn’t been apparent from the written material that has been published by HS2 Ltd. However, the real test will come further down the line when HS2 Ltd feels that it must say no to a proposal from the locals.

At that point the smiles will probably be wiped off our faces.