I went along to the A303 public consultation at Shrewton yesterday and received the following information:
1. How much of the Stonehenge tunnel spoil will be taken offsite?
A: Virtually none. As far as possible, all of it will be re-deployed in other areas, including building up the embankment levels on the W-S bypass routes. The cost of taking spoil offsite is prohibitive (£140 a ton) and there is very little leeway within the total project cost (£1.4b) to remove significant amounts of spoil offsite.
2. Does the amount of tunnel spoil have any impact on the height of embankments and viaducts?
A: Yes! (See previous answer)
3. Why are the heights of the viaducts and embankments on the proposed northern bypass route so much higher and more visible than they were on the previous Government’s preferred northern bypass route that was published in 2006?
A: Primarily due to the need to re-deploy spoil from the Stonehenge tunnel and keep within budget.
4. To what extent have you assessed the impact of the prevailing wind on dwellings as part of your noise impact survey?
A: It hasn’t been measured at all not have the heights of embankments. A more accurate noise impact survey will be conducted, but only after one of the proposed routes has been chosen.
5. What level of noise has been assessed as “acceptable” in the noise impact surveys?
A. The noise assessment surveys that have been done have followed World Health Organisation guidelines on what constitutes an acceptable level of noise, which is anything up to 55 decibels (db). The traffic noise that has been measured on the high street in W-S is 72db. This implies that while the northern route might result in an overall improvement in noise levels in W-S (as those houses currently adjacent to the A303 will see traffic noise fall from current levels of 72db), that it was very possible that for the southern half of W-S and all of Berwick St James, noise levels would increase significantly but remain “acceptable” (ie below the 55db threshold)
6. What impact do recent archaeological discoveries have on the precise location of the A303 junction for the northern route to the west of the A360?
A. Very little. There have been some recent archaeological discoveries including some new long barrows and a henge, but these have been found to the east of the A360 and within the WHS. There is room to shift the northern junction further east towards the A360 but the southern route (and its junction) is currently slightly more favoured because the site of the southern route junction is lower down and less visible from the WHS
7. How accurate are forecasts for future traffic usage of the A303 once the tunnel and bypass is opened?
A. Hopefully reasonably accurate although the models that were used to predict volumes of traffic using the A3 Hindhead tunnel (1.2 miles) and dual carriageway (4 miles) which was opened in 2011, severely underestimated the increase in traffic. Highways England had predicted that one year after opening in 2011, average daily traffic (AADT) would increase from 30,000 to 36,000 (20%) whereas it actually rose from 30,000 to 40,000 33%). The traffic models failed to capture the increase in traffic volumes as improved journey times encouraged drivers to shift to road from other modes of transport (rail), shift routes, and make journeys that they wouldn’t have made before the tunnel and dual carriageway were opened.