tinyurl.com/noisebarrier

Reducing Noise from the A413 Wendover Bypass (Summary)

New - Survey

When you've had the opportunity to review the information on this page, we'd like your opinion on which option you'd prefer. Click here to take our short survey.

A more detailed version of this page, with more information, associated numbers and supporting evidence, can be found by clicking here.

Wendover Bypass north Wendover Bypass south

Background

Ever since the Wendover Bypass was built, it has generated traffic noise which affects much of Wendover. In September 2015, HS2 offered to pay for noise barriers on the A413 Wendover Bypass which "Improves the acoustic character of Wendover in general by reducing the continuous ambient traffic noise that affects it". The reason they made this offer, in line with government guidelines, was to compensate for their failure to fully mitigate against train noise by reducing some of the existing noise affecting Wendover.

Bucks County Councilís current plan is different from that originally proposed by HS2. This now to build two wooden fences along the bypass, to the north of the Ellesborough Road overbridge and a separate short section to the south. The height has been increased from 2m to 4m (13ft).

The purpose of this web page is to summarise the facts in connection with this proposal and also the main alternative, the use of a low noise surface. Bucks County Council have received advice from specialist noise experts, and the information on this page is based on this and on publically available reports.

Road noise

Traffic Noise

For a listener at a significant distance from a road, the noise which will be heard comes from many vehicles along a considerable length of road. At present most of Wendover generally hears this as a background hum from the bypass traffic. Small changes in noise level are not normally noticeable. When looking at any sound mitigation, it has to reach a certain level of noise reduction to be effective.

Benefits of proposed noise barriers

Wind Noise

Sound from a road is transmitted to neighbouring houses in two ways. For houses close to the road, the sound follows a direct path from its source to its destination. However at a greater distance, wind plays an important role. Sound which initially travels upwards from the source is bent back downwards in the direction of the wind, as a result of the variation of wind speed at different heights. As a result, a significant amount of noise can often be heard at some distance downwind of the noise source, as is the case in Wendover. Noise barriers are effective at blocking the directly transmiited sound, but have little effect on wind-borne noise, as this initially rises above the noise barrier. The benefits of noise barriers are greatest at a short distance from the noise source, and reduce significantly behind other houses which themselves act as a barrier. An adverse wind (blowing from the road) reduces the benefit for all properties.

In the context of Wendover, the properties which will benefit from the noise barriers mostly lie in the roads to the south-west of Dobbins Lane (i.e. between Dobbins Lane and the bypass); houses between Dobbins Lane and the Aylesbury Road or along/near Hale Road, which mostly suffer from wind-borne noise, will get no significant benefit.

At 13ft high, the noise barriers will be quite visible, and are likely to attract graffiti. They are permanent structures which will cut across the view of Wendover, for example from Coombe Hill, and will be a further intrusion on the AONB even where HS2 is in a tunnel and so is not visible.

An alternative: low noise surface

Jacobs noise maps

An alternative method of reducing traffic noise is to lay a low noise surface on the road. These have been available for many years, and have steadily improved. One of the best surfaces now available, described as vLNS (very low noise surface), is being applied by Highways England to 10 miles of the A14 in Cambridgeshire as part of what is currently the largest road building project in England. This could be applied to the Wendover Bypass.

In the case of Wendover, this type of vLNS would provide significant noise reduction for all homes which currently suffer from noise from the bypass, extending at least to the Aylesnury Road and Hale Road. More than five times as many homes will therefore benefit from a vLNS than from noise barriers, and the level of benefit is well above the level at which a benefit is noticeable. Because a vLNS reduces noise at source, its benefit is not affected by wind or distance. The diagrams on the right illustrate these benefits.

One reader of this website commented as follows: "Great work. I've long thought a low noise surface would be the best solution for Wendover generally, regardless of HS2 to be honest. Having observed how quiet the surfaces can be on the continent a similar approach to the Wendover bypass would make a huge difference"

A recent article in the Bucks Free Press describes how the installation of a 4m noise barrier on the M40 in Stokenchurch has not made the noise any better. Residents have signed a petition asking for the barrier to be reduced in height because of its appearance ("a complete eyesore"), and for a low noise surface to be installed.

Costs

Both solutions require maintenance after initial construction. A noise fence needs regular treatment and normally replacement after 20 years. A vLNS requires resurfacing every 10 years and replacement after 30 years. A low noise surface is significantly cheaper than noise barriers over the same length, both for initial construction and maintenance.

HS2 construction traffic

Concern has been expressed about the additional noise from HS2 construction traffic on the bypass, especially from engines, transmissions and exhausts; indeed this has been much of the reason for progressing the noise barrier proposal, though was not part of HS2's original rationale for offering the money. However construction traffic will only represent 3% of traffic on the bypass. It has been quite difficult to obtain any estimates of how much noise this construction traffic will cause. We have therefore attempted to estimate this ourselves. The conclusion is that the additional noise will be well below the minimum noticeable. And this is peak rather than average noise. Even allowing for the possibility that HS2's estimate of HGV volumes is an under-estimate, it is unlikely to exceed this minimum.

The importance of this is that the best long term solution can be chosen without needing to consider short term HS2 construction traffic noise.

Additional concerns have ben expressed regarding HS2 construction traffic, but none of these are valid:

Availability of money

When this funding was originally offered in 2015, HS2 considered the low noise surface option and concluded that noise barriers would be more cost effective, so they offered funding for these. However the situation now is very different, as a result of improvements in the effectiveness and costs of low noise surfaces.

Although the original Undertaking and Assurance (U&A) from HS2 states that the funding should be used only for noise barriers, according to information provided to Bucks County Council (BCC) by HS2 it would in fact be possible for that to be changed given certain conditions:

"If there is a desire for a variation to the U&A (move from a noise barrier to low noise road surface); then BCC must demonstrate through a business case that the new proposal will cost no more than the noise barriers. The new proposal must also be fully committed to by BCC and there should be no expectation of further funding from HS2 for maintenance in the future."

It has been suggested that we might ask Bucks County Council for a low noise surface once HS2 construction is complete. However once the noise barriers are in place and the HS2 money is spent, it might be difficult to persuade Bucks County Council of this.

Speed limits

The introduction of a lower speed limit on the bypass has also been suggested. If notwithstanding the arguments presented here, the noise barriers go ahead, the additional noise reduction from imposing a 50 mph speed limit might just be sufficient, in conjunction with the noise barriers, to bring about a noticeable noise reduction across a wider area of Wendover than noise barriers alone, albeit still very much inferior to the benefit of a very low noise surface.

Survey

Now you've had a chance to review the information on this page, we'd like your opinion on which option you'd prefer. Click here to take our short survey.

Wendover HS2