10-25% increase in traffic forecast for the A371 in Winscombe within 2 years of the opening of the Banwell Bypass

WinTAG met with a member of the Banwell Bypass Working Group to find out what North Somerset Council is saying about the traffic forecast for Winscombe when the bypass is built.

Q: Who is on the Banwell Bypass Working Group?

A: The Working Group has representatives of the council’s Banwell Bypass Team, the parish council for Winscombe and Sandford and residents’ groups such as Greener Church Road Group, Sandford Neighbourhood Group and Community Speed Watch.

Q: What is the council forecasting for the traffic in Winscombe once the bypass is built?

A: The Banwell Bypass Team says that the average daily traffic on the A371 is expected to increase by between 10% and 25% within 2 years of the bypass opening.

In 2019, the average daily traffic recorded on the A371 was 7541[1] vehicles. These figures are the last available prior to the pandemic. In 2020 the figure was 5643. As expected, this was lower than the figure for 2019 but at the end of 2021 we are seeing a gradual return to the 2019 ‘norm’.

If the traffic situation prior to the opening of the bypass in 2024 was to be similar to that in 2019, by 2026 there could be between 8295 and 9426 vehicles a day using the Southern Link Road and Woodborough Road between Banwell and Winscombe. The northerly flowing traffic would include that joining the A371 from Church Road, Sandford Road, the Lynch and other side roads. Some of the southerly flowing traffic on the A371 would turn off onto these same roads.

The figures for traffic on the A371 therefore do not represent the total of vehicles using Winscombe’s roads. We need to consider too that some of the traffic recorded on the A368 between Sandford and Banwell[2], will use Hill Road and Sandford Road to and from Winscombe. The forecast of a 10-25% increase in daily traffic also applies to the A368. We now have data for traffic volumes and speeds on four roads in Winscombe in October 2021 These are currently being analysed and once the results are available we will report these to WinTAG.

The Banwell Bypass team also states that as a result of the bypass, the average increase in vehicles on the A371, at peak hours, will be between 100 and 150. In 2019, the peak traffic flow on the A371 was 947 vehicles. The new total peak hour traffic could therefore be between 1047 and 1097 vehicles by 2026 as a result of the bypass.

Q: That sounds like a big increase in just 2 years. What about the situation after 5, 10 or even 20 years?

A: To date the council has been unable to supply these figures. The bypass team will forecast traffic flows for 2039 (15 years after the bypass opens). We know from the experience of other bypasses, that traffic can increase by 50% within 7 years as a result of the new road although increases like that usually take longer. This increase is made up of induced traffic on the bypass itself but there is often also an increase in traffic on the road it is designed to remove traffic from.

Traffic will still be able to use Banwell village centre although we are told that measures will be put in place there to benefit residents, walkers and cyclists. According to the Campaign for Better Transport[3], actual traffic increases are usually far higher than those forecast. These percentages apply to the impact of the bypass alone and do not take into account population growth or new house building.

Q: What about the 3000 plus new houses to be built in Banwell, and the new houses in Winscombe and Cheddar? How will these affect the amount of traffic?

A: The council has not supplied us with information about the impact of new house building but we have looked at the assessments it uses when considering planning applications from developers. Using the council’s formula[4], we calculate those 3000 houses could generate an additional 1451 car trips per hour at peak time. We estimate that about 300 of the car trips linked to the new houses in Banwell could use the Southern Link Road and the A371. We would need to add these to the forecast total peak hour traffic of between 1047 and 1097 vehicles resulting from the bypass alone. This gives new totals of between 1347 and 1397 vehicles per peak hour on the A371, up from the 947 last recorded in 2019, an increase of about 50%.

Of the additional car trips resulting from the 3000+ new houses forecast for the A368, some would use Hill Road to and from Winscombe, adding to the peak hour totals in Winscombe. Then we will need to add on the additional traffic generated by new houses in the village and in Cheddar. By the time the houses are built, the overall level of traffic will have increased so the new peak hour totals would be even higher.

Q: We have heard that the council is planning improvements to the M5 junction 21. What difference will this make to our traffic?

A: We have been given no information from NSC about the impact of an improved motorway junction on our local traffic. However, one can imagine that if these improvements make it easier for traffic to go straight from the motorway onto the Banwell Bypass and then onto our roads (which is something the council is encouraging), we will indeed see an impact. There is a danger that once this traffic enters our smaller, rural, residential roads and lanes, it will exacerbate our problems.

A related point is that the Banwell Bypass team has told us that the costs of improvements to the motorway junction will come from the same budget as the costs of mitigation so we are concerned that this could leave far less money for mitigation work.

Other factors in an increase in traffic are the population growth expected in our area and other developments, planned and unplanned. You can see why residents are keen to know more from the council about how they will be affected by all these changes. Without this information, how will we know what mitigation is needed?

This will be discussed in our next article on this topic.

For further information about the implications of the Banwell Bypass for traffic in Winscombe, please contact winscombetag@gmail.com


[1] Source – NSC’s road traffic statistics

[2] Sandford Neighbourhood Group traffic information can be found at https://winscombeandsandford.org.uk/category/sng/

[3] https://bettertransport.org.uk/roads-nowhere/bypasses-dont-work

[4] NSC-accepted traffic assessment for the Aurora housing development in Sandford

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