Why we are opposing any widening of Cock Lane.
First may I thank you and your colleagues, Matthew Hardy and Hannah Bishop for our meeting on 13th May which we all found most useful. As you know, we very much want to keep the current narrow Cock Lane with its over-arching hedgerow trees which we feel is a vital part of its historic character and reinforces the sense of separate settlement, but is also effective in achieving a reasonable flow of traffic. We undertook at our meeting to set out more fully the issues that we raised with you and relate them to the prime concerns of BCC Highways.
Our overall objective is to keep Cock Lane in its current form, but with some modest improvements to sight lines, road edges and passing places. It is our view that the existing character of Cock Lane, especially the narrow section and also the section with the alternate-working signals over the railway bridge to the south, has a very desirable effect on discouraging through traffic. We contend that moves either to increase its capacity (e.g. through widening) or to by-pass it (i.e. via the Little Haldens site) would have the effect of attracting significant traffic to it, and therefore through Tylers Green, and past the Middle School.
It is now firmly established that the new spine road, the route through the site – between London Road and Cock Lane via Gomm Road – should not be routinely used by through traffic. This is emphasised in the Wycombe District Local Plan (WDLP), the most recent and authoritative of the relevant documents.
5.1.46 The purpose of this spine road is to distribute traffic from the development. It is not intended to act as an unofficial ‘bypass’ as this would be detrimental to Penn and Tylers Green due to the increase in through traffic. The capacity of the spine road and the northern end of Cock Lane must therefore be restricted through effective traffic calming to deter through traffic.
The Gomm Valley & Ashwells Development Brief also states (5.1.2) that:
It is important that this highway improvement does not lead to a significant increase in traffic using
Cock Lane and the new spine road because of the detrimental impact that would have on the village of Tylers Green
The approach we are advocating is entirely in keeping with these statements. The northern (narrow) section of Cock Lane acts as a very effective measure for deterring through traffic and should, accordingly, be maintained in its current character.
We will now address three important issues that specifically fall within the remit of BCC Highways.
In numerous documents in the public domain, BCC Highways have made references to their belief that Cock Lane has to be widened for reasons of highway safety.
We strongly contest this assertion. As the Odyssey Traffic Assessment in the Ashwells Planning Application notes:
3.7.8 Given the fairly minimal number of incidents, the low severity and absence of recurring trends, it is reasonable to conclude that there is not a significant highway safety problem within the vicinity of the site”
The report says there have been only 3 minor accidents on Cock Lane over the last 5 years. Furthermore there have been no accidents in the length of Cock Lane that BCC Highways wishes to widen.
We would further point to the highway safety issues that will be generated if more than twice the current level of peak AM traffic is ‘induced’ into a widened Cock Lane and Spine Road.
“The AM Peak in 2026 (without development or the Spine Road) shows Cock Lane accommodating 647 two-way vehicle movements. The AM Peak in 2026 with the Gomm Valley and Ashwells Development shows Cock Lane to the north of the Spine Road to be carrying 1,317 two way vehicle movements.”( C.Urry BCC 20/9/2017)
265 pupils at the Tyler’s Green Middle School on Cock Lane would be subjected to more than twice the current levels of CO2 pollutants at peak AM. The increased potential for accidents, as all children cross this winding section of road, must also be taken into account under Highway safety.
This theme of safety is inevitably connected with the issue of capacity which we consider next.
There have been various references in public documents to ‘capacity’ with regard to Cock Lane and the need for a Spine Road. Theyl assume that Cock Lane is at capacity and that increased traffic from the new developments will necessitate the widening of its northern section, with a northern junction into a new Spine Road.
The Odyssey Transport Assessment for the Ashwells development states (Table 3.1) that Cock Lane current two-way traffic numbers at peak times are as follows: AM peak,348; PM peak, 265.
Table 3.4 states the Journey Time through the narrow section of Cock Lane as AM peak: North=1.98mins, South=1.48mins. Using their measured distance of 750m, the times through the
narrow section convert to 14mph heading North and 19 mph heading South. This is significantly better and faster than the 6mph being achieved by traffic heading east at peak time on the nearby A40 London Rd.
The assertion about Cock Lane being at capacity is presumably based on the Department of Transport Advisory Leaflet 02/2004, ‘suggesting’ that “to prevent excessive delay…..maximum 2 way vehicle flow on a single track road should not exceed 300 vehicles two way per hour”. However, para 4.2.4 of the Odyssey TA clarifies that up to 300v/hr, 2-way, “single lane ways are unlikely to incur significant….delay compared with traffic in free flow conditions”.
Therefore, 300v/hr is not the absolute capacity, just the point at which delays might occur compared with traffic in ‘free flow’ conditions. But at AM Peak Hour no roads in the area will run in ‘free flow’ conditions, and as we have noted above, the A40 London Road at that point and time is running at 6 mph.
Even more compelling, an additional PEP document ‘Transport Assessment part 1’ ( para 7.4.6) indicates that there had been no growth in peak hour traffic flows in Cock Lane, Hammersley Lane, London Road area in the last 4 years, while para 7.4.8 reports a 14% fall in High Wycombe flows since 2000. They conclude that ‘the current growth forecasts do not provide realistic future traffic profiles’.
Para 7.4.7 indicates that BCC accepts this lack of growth ‘in principle’, whilst still wanting their growth model used for forecasting. The reason for this is not understood.
We therefore challenge the assertion that Cock Lane is at or near capacity. Future growth may even be negative if current trends continue. We maintain that Cock Lane will be able to cope with the small additional traffic flow from the new developments. This may cause a small increase in delays, but this is to be offset by the proposed improvements to the single lane section (better sight lines, more passing places, better signage).
As we said in our introduction, we also contend that the nature of the narrow section of Cock Lane acts as a natural traffic calming configuration and has the desirable effect of discouraging through traffic which accords with the wording of the Local Plan and The Development Brief as quoted in our introduction.
3. Convenience of use
We have shown above why we believe Cock Lane is not at capacity, and why forecast growth rates are contradicted by the trends in traffic reduction. We maintain that the smaller improvements we have suggested will improve visibility and make the road safer and more convenient for its users.
Many drivers do not like single track roads at any time of day and they make rational decisions to avoid them, particularly at peak times. Others choose to use them when it suits them.
Given some limited improvements of the type already suggested, we believe Cock Lane will continue to be convenient for some local users as at present. It will also easily cater for the small additional traffic estimated from the new developments.
WDC’s Development Brief for Ashwells has stated that It is important that this highway improvement does not lead to a significant increase in traffic using Cock Lane and the new spine road because of the detrimental impact that would have on the village of Tylers Green. Widening Cock Lane will inevitably result in just such an unacceptable increase in traffic through Tylers Green and we maintain that we have demonstrated that it is not justified either by considerations of safety or capacity
cc. Katrina Wood Leader WDC
Penelope Tollitt, Head of Planning and Sustainability, WDC
Robert Harrison, Principal Development Management Officer, Planning & Sustainability, WDC