Two additional lanes are being added in both directions on the A10 Zuid. They are intended for traffic heading for Amsterdam. Next to them is the main roadway, consisting of four lanes and intended for through-traffic. All of these major changes were preceded by countless investigations and surveys that ultimately formed the basis for the Zuidasdok Routing Decision (Tracébesluit Zuidasdok), drawn up in 2016. Many of those investigations looked into the impact that regenerating the A10 Zuid will have in terms of noise. But how do you investigate something like that? Hans de Haan, a consultant specialising in noise, has been doing it for years. ‘Since the future hasn’t yet happened, it’s impossible to measure future noise. That’s why we need computer models’, he says. ‘Using these models, we’ve investigated the noise impact for thousands of homes and other places that are vulnerable to noise, such as schools and hospitals. We also looked at the measures needed to curb that impact. That’s our ultimate aim: preventing an increase in disruptive noise.’ Noise barriers play a crucial role in that, but they are not the only factor. ‘The type of asphalt used also makes a difference’, explains De Haan.
Additional barriers
In addition to the noise barriers stipulated in the Routing Decision, it was already known in 2016 that the City of Amsterdam wanted to have additional barriers in several places. De Haan: ‘They’re not included in the Routing Decision, because they’re not required by law. Amsterdam has added them in order to provide additional protection for areas where silence is a key factor in determining quality.’ Places where there are plans for additional barriers include the AFC sports pitches, next to Beatrixpark, Amstelpark and Tennispark Joy.
Standards and constraints
The effectiveness of a noise barrier is determined to a large extent by its height and length. ‘It’s a case of finding the ideal combination, within the parameters of the applicable standards and financial constraints’, says De Haan. ‘We know that an increase in the height of a barrier from 2 m to 3 m is more effective in relative terms than an increase from 5 m to 6 m. We use numerous variables in order to calculate what will deliver the greatest relative noise reduction. This basically involves developing lots of small designs and seeing which works the best.’
Close to the source
The A10 Zuid will not only have roadside noise barriers along the new lanes that are for through-traffic, but also between the main roadway and the parallel lane. The closer a barrier is to the source of noise, the more effective it is at reducing it. Some of the barriers will also absorb sound. These are made of materials such as concrete core panels, on which climbing plants can also grow. Noise-absorbing barriers will not be used next to subways or underpasses. To ensure social safety, transparent barriers need to be used in these places, in order to allow daylight to enter.
Change to Routing Decision
In the period between 30 November 2022 and 10 January 2023, the changes to the 2016 Routing Decision were open for consultation. The changes referred to additional hard shoulders and modifications to the design of the tunnel entrances on the southern main roadway and parallel lane. ‘We’ve done a lot of new research into the acoustic effects in order to make sure that the changes don’t make them worse. According to our recalculations, we’ll need to apply additional measures at six locations: at the southern tunnel entrances and in two places between the Rozenoordbrug bridge and the S109.’ The solution will not involve installing taller noise barriers, but using an even quieter type of dual-layer porous asphalt (2L-ZOAB fijn). This absorbs noise even more effectively than the dual-layer porous asphalt being used for all the other sections of the A10 Zuid.
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