Traffic Noise Assessment

B L Acoustics were commissioned to carry out a Calculation Road Traffic Noise (CRTN) survey at a depot in Slough. There is currently a planning agreement for the redevelopment of the site’s existing vacant car park and the trans-shipping facility there.
The distribution centre and head office in Slough has a reasonable level of traffic in and out of the premises, some of which is heavy goods vehicles that come in and out of the premises throughout the day and night.
The purpose of our survey was to establish the current impact of deliveries and departures on the nearest dwellings, and then to assess the effect the proposed development would have on this.

Prior to surveying, B L Acoustics completed a desktop review of the planning proposal and existing site layout. Then, by consulting with the client, we were able to best understand the potential issues and possible concerns the council may have with the development. This was critical to ensuring we delivered what was needed for our client.
Prior to attending we had assessed and agreed what noise sources should be measured and the key noise sensitive receptors that will need to be considered.

We advised a full 24-hour environmental noise survey would be completed using the existing conditions. This combined with CRTN method predictions would allow for a high level of assurance when predicting the effect of the development on neighbouring residents. Our client was in agreement and a full assessment of the road traffic noise was completed, with specific focus on the noise generated by traffic movement in and out of the existing delivery entrance, and the impact on residents in the nearby area.

Monitoring of the background noise around the site was recorded over a 24-hour period. Specific noise measurements were taken at the time of deliveries/collections where the monitoring station was located, with a full 24 hour (plus) recording undertaken by the environmental survey equipment. The monitoring station is ideal for long period surveys with a large internal memory. With fully weather proof enclosures, it can be set up and left in situ to collect all the data required.

The principle purpose of the CTRN Memorandum is to assess whether noise traffic noise will have an adverse effect on residential properties. It is then possible to consider is noise reduction is required and what level will be sufficient to satisfy the planning requirements.

The client’s premises are located on a typical industrial road where traffic ebbs and flows throughout the day. It provides access to a number of branched side roads serving other industrial units on the estate. At the time of the survey, England was out of the Covid-19 full lockdown and the site had confirmed a return to normal levels of traffic.

We completed two visits. During the first, we installed environmental monitoring equipment at an agreed location adjacent to the main entrance of the site. Whilst here, we completed a number of short measurements at locations around the junction and near the closest situated building. These were later used to validate the principle survey results and analysis.

The outcome of our survey was positive. The sound levels at the junction did not exceed 68dB LA10_(16H), and the calculated levels at the façade of the nearest dwelling were significantly lower than this. Therefore, we concluded the monitoring position offered a worst case scenario with respect to traffic created by the site. The overnight monitoring highlighted, as expected, a huge drop in sound levels, and didn’t point to any reason for concern over the existing road movements.

Ultimately, the noise level measured at the road side of the entrance was found to be 66 LA10, 2dB below the actionable level of 68dB. Therefore, based on our findings and in line with CRTN procedures of measuring and the Noise Insulation Regulations 1975, we recommended no action was taken to mitigate the road noise levels.

This recommendation was accepted by the council, thus allowing the planning process to proceed, and ultimately helping achieve the development.

If you have any enquiries about assessing noise in your area or business, please don’t hesitate to get in touch.