A27 Arundel Bypass

[RichardEvans67]

OK. I stand corrected.
(At least to some extent).

[RichardA35]

OK. I stand corrected.
(At least to some extent).

Also, importantly, trees cannot be considered as noise mitigation as they tend to lose their leaves in winter (especially deciduous ancient woodland). The scheme noise mitigation, if needed, will generally be by earth bund or environmental barrier (fence).

[RichardEvans67]

by RichardA35 » Wed Jun 06, 2018 14:45

Also, importantly, trees cannot be considered as noise mitigation.

Well I just can't help thinking about the dual near me, and not noticing the sound of the traffic until I get within about 50 yards of it. And into the trees around it. But perhaps the lack of noise may be more to do with it being in a slight cutting. Although I still suspect the trees may help.

[RichardA35]

by RichardA35 » Wed Jun 06, 2018 14:45

Also, importantly, trees cannot be considered as noise mitigation.

Well I just can't help thinking about the dual near me, and not noticing the sound of the traffic until I get within about 50 yards of it. And into the trees around it. But perhaps the lack of noise may be more to do with it being in a slight cutting. Although I still suspect the trees may help.

There is considerable science behind the noise prediction models but simplistically it all comes down to a bit of pythagoras. Once the noise level at a property is adjusted for distance and other factors, the length of the path of the noise is calculated as a direct line from the tyre/road interface to the receptor (your ear or house facade). The actual length is then calculated that the noise has to travel bending or refracting around the top of a cutting or noise barrier to reach the receptor (this is where pythagoras is used). The difference is calculated and the reduction in noise at that distance is proportional to the noise path difference. Do this in three dimensions and you have a predicted noise model - simple really! For example a path difference of 0.5m reduces noise by some 12dB(A) which is really significant although hard to achieve.
Where vegetation is present some account is taken as an absorbent surface but that could also be grass with also an assumption that the noise level predicted will probably be overstated.
If you fancy a bedtime read Google is your friend for "Calculation of Road Traffic Noise"
Coincidentally p94 is the section regarding "screening due to a road in a cutting"

[Bryn666]

Conversely drive around the A10 in Amsterdam and there are noise walls flanking the motorway. They're about 3 metres high. Must be ugly to look at though!

[RichardA35]

Conversely drive around the A10 in Amsterdam and there are noise walls flanking the motorway. They're about 3 metres high. Must be ugly to look at though!

M25 M3 - J13 and the same round the Lyon area (A43 heading to Grenoble) - noise bounces between them and exits skywards but the properties in the shadow zone have a far reduced noise level than if they were not present.

[Chris5156]

by RichardA35 » Wed Jun 06, 2018 14:45Also, importantly, trees cannot be considered as noise mitigation.

Well I just can't help thinking about the dual near me, and not noticing the sound of the traffic until I get within about 50 yards of it. And into the trees around it. But perhaps the lack of noise may be more to do with it being in a slight cutting. Although I still suspect the trees may help.

I don't think Richard would disagree that woodland around a road can dampen the sound of traffic and reduce the effect of road noise on surrounding areas. That almost certainly does happen. The point is just that, if you're planning a new road like the Arundel Bypass, the rules of an environmental assessment don't allow you to claim the surrounding woodland as a noise mitigation feature because the effect it can have is difficult to quantify, it varies through the year, and is liable to change because the amount of woodland surrounding the road is not usually within the control of the highway authority. So if a patch of woodland surrounding a new road were to be claimed as noise mitigation and, for example, the landowner later decided to clear the woodland and sell the land for housing, the noise mitigation would be gone and there would be nothing the highway authority could do. Whereas the things that can be counted as noise mitigation - the slope of the cutting the road is in, or an earth mound, etc - are engineering features of the road that the highway authority can guarantee will not be removed and will have a stable, unchanging effect.

[Bryn666]

Conversely drive around the A10 in Amsterdam and there are noise walls flanking the motorway. They're about 3 metres high. Must be ugly to look at though!

M25 M3 - J13 and the same round the Lyon area (A43 heading to Grenoble) - noise bounces between them and exits skywards but the properties in the shadow zone have a far reduced noise level than if they were not present.

Oh absolutely don't dispute they work; they're just not pleasant structures. The ones in Amsterdam are, I think, at least designed to be multicoloured etc.

Incidentally weren't the clear perspex noise screens first used in the UK on the M65 J1a-6? There are two underbridges using them; one between the M61 and M6 junctions and another with the A666 at J4.

[RichardEvans67]

by RichardA35 » Thu Jun 07, 2018 08:00

Once the noise level at a property is adjusted for distance and other factors, the length of the path of the noise is calculated as a direct line from the tyre/road interface to the receptor (your ear or house facade). The actual length is then calculated that the noise has to travel bending or refracting around the top of a cutting or noise barrier to reach the receptor

I was expecting the attenuation to be a fair bit more than that. If the noise has to travel upwards to get to the top of the barrier, and then has to change direction to end up back on the ground, then I would have thought the main effect would be diffraction. Which is basically spreading out, so diffracted waves tend to be a lot weaker.

But I suppose refraction would play a part depending on the conditions, (I expect refraction would probably be strongest in the evenings). Refraction wouldn't significantly weaken the waves, so I suppose they would have to calculate using the maximum possible refraction conditions, which could be quite a lot.

[wrinkly]

Press release

https://www.gov.uk/government/news/arun ... ext-spring

[jackal]

Not sure what the point of this is. They seemed to make a clearly correct choice first time round.

[Bryn666]

Highways England about to snatch defeat from the jaws of victory it seems...

[Berk]

Sorry, but why wasn’t this information available just a few months ago??

[Euan]

I'm sure I read somewhere that building new roads is often a bit more restrictive if they are proposed within the boundaries of a national park. The western end of the planned route of the Arundel bypass clips the edge of the South Downs NP, but I wouldn't imagine this being the reason for bringing the proposals back to the public at this stage as it would have been taken into account much earlier in the process.

[jackal]

The press release mentions that HE will be continuing their legal defence of the preferred route. Perhaps this is to show the judge they've given the alternatives a fair shake.

[GeekyJames]

maybe they're planning on amending the Western Edge end of the scheme so that it avoids the SDNP?

[Berk]

I think people need to be realistic about this (this project, and similar ones). Clipping the edge of a national park by a few hundred metres does not mean it’s ‘ruined forever’. They managed to build the A30 improvement near Okehampton without ruining Dartmoor.

All objections achieve is delay, and cost increases. And less money for environmental protection along the route.

[GeekyJames]

So now that Highways England are holding a supplementary consultation next year the SDNPA have withdrawn their legal challenge...

https://www.littlehamptongazette.co.uk/ ... ARtdD9JLm8

[GeekyJames]

Latest update on the Arundel Bypass, looking at the time frame there's not even a date pencilled in for construction now!

May 2018 Preferred route announcement
2019 Further non-statutory public consultation
TBC Submit application for a Development Consent Order under the Planning Act 2008
TBC Start construction

Community news

We held our first A27 Bypass Elected Representatives’ Forum on the 21st November 2018. It was a constructive discussion, with the main topics including the timeline for both further consultation and construction, reasons for further consultation and the environmental mitigation, design and budget of the scheme.

The next meeting will be held on the 26 February 2019. If you have any questions or would like to get in touch with the A27 Arundel Bypass project team, please email: a27arundelbypass@highwaysengland.co.uk.

The Elected Representatives’ Forum provides a way for us to engage with communities local to the A27 Arundel Bypass scheme. The forum will help local communities, via their elected representatives, to find accurate, up-to-date information about the scheme through the consultation and planning stages and what they can expect – for example, emerging evidence and design options. It is also a way for the local communities to understand what the scheme means for them and how it will progress over the years.

[Euan]

There are no other viable options for the route of the bypass other than to pass just south of the woodland and Arundel itself, so not really that much can be done to satisfy any objectors to the route in its current form. The only alternative of course would be to have no bypass and achieve nothing.