Islip Bridge (River Ray, Islip) Bridge Protection Works (Provision of Kerbing, Traffic Signals & One-Way)

Following an earlier consultation carried out in November/December 2020 (for details click here) regarding the proposals to introduce a one-way restriction on Mill Street in Islip in the vicinity of the river bridge, Oxfordshire County Council is now consulting due to the concerns that were raised related to the provision of traffic signals, which was not the focus of the original consultation.

This further consultation on these measures to better inform on the need for the proposed measures to the bridge, is now being carried out, for which your comments, concerns are welcomed to help in the detailed in the proposals to minimise their adverse impact and to maximise any benefits that can be obtained. These measures are necessary to protect the bridge, and to avoid the need to close it for an extended period of time, potentially several years.

This bridge was re-built in 1878 and consists of three brick arch spans, with stonework parapets, ‘voussoirs’, spandrel walls and approach retaining walls. The clear width between the bridge’s parapets is 5.3m, without any raised verges, for improved drainage or protection to the parapets. The average size of vehicles has increased by over 50% within the last 50 years. With the popularity of SUVs the average width of the top 20 vehicles has increased by nearly a foot within the last 20 years. Vehicles squeezing past one another on the bridge and overrunning the area designated for pedestrians has increased the loading on the edges of the bridge resulting in damage to the arches in the form of cracking and separation of the spandrel walls from the rest of the arch barrel. With no raised verges and with surface water running up against the face of the parapets, water has run down these cracks through the structure accelerating the damage. The minimum width of a carriageway to current highway standards for a two-way road is 5.5m. Ideally, the roads through the village and across the bridge would be widened, or a bypass built, but this is not practical within the time required to address the current problems with the bridge before it becomes unsafe and necessary to close it. The bridge cannot readily, or reliably be repaired or widened, so would need to be reconstructed, which would cost in the region of £5m and take several years to arrange and is considered not to be warranted by other higher spending priorities. Widening the bridge, without widening the road on its approaches, which would require the demolition of many properties, would appear to not make much sense and would ruin the character of the village. There is the opportunity now to safeguard the bridge and to keep it open, before it deteriorates so far than there is no option left, but to re-build it.

The safeguarding measures required are relatively simple, providing kerbs each side with raised verges to keep surface water away from the face of the parapets and vehicle loading off the damaged edges of the bridge. It is intended to make one of these raised verges slightly wider than the other, such that within the available width of the bridge a suitable footway can be provided. Unfortunately, this simple effective and reliable solution is complicated by the narrow roads on the approaches and junction layouts at either end of the bridge, and the poor approach visibility to either end of the bridge. The only viable safe means of maintaining two-way traffic flow over this narrow-damaged bridge, is by the introduction of traffic signals. The only identified means of preventing gridlock on the narrow roads on the northern side of the bridge, is by making a section of Mill Street one-way. Without this queuing traffic on Mill Street heading south across the bridge, would block traffic heading north.

The consultation on the making of Mill Street one-way has raised many concerns as has the provision of traffic signals. The concerns about the traffic signals largely appears to have resulted from the previous experience of temporary two-way traffic signals on the bridge, where the temporary stop lines were positioned such that queuing traffic blocked traffic coming in the other direction, causing gridlock. The proposed permanent traffic signals resolve this problem by moving the stop lines further back, necessitating the provision of 3-way signals, with signal heads on Lower Street and King’s Head Lane and making Mill-Street one-way. Unlike temporary traffic signals these permanent signals will have sensors detected approaching traffic and computer controlled automatically adjusting timings to minimise queuing. Traffic modelling and a safety audit has been carried out for the proposed traffic signals. The proposed timings will prioritise southbound traffic and ensure that traffic queue lengths, do not go pass the top of King’s Head Lane at peak traffic flow times. Queuing traffic on King’s Head Lane is currently a problem with traffic having to currently give-way to traffic from Mill Street. A high proportion of this traffic from Mill Street appears from the traffic modelling to be commuter through traffic “rat running” down Church Lane. The proposed making of a section of Mill Street one-way will stop this.

After taking into account the issues raised within the detailed design as far as practicable, carrying out the procurement, including obtaining specialist components for the traffic signals which have a relatively long manufacturing time, it is anticipated that the measures to protect the bridge will be put in place by the Spring of 2022. The condition of the bridge is being monitored and it cannot be accurately predicted how quickly it will further deteriorate. It is hoped that this will be quick enough to avoid having to put in alternative measures to safeguard the public and the bridge, e.g. temporary vehicular barriers along the edges of the bridge with temporary traffic signal control, or a road closure. In the meantime, please try to avoid driving close to the face of the bridge parapets, giving way to larger vehicles as far as practical, such that this does not force them to drive up against the face of the bridge’s parapets.

The proposed design of the traffic signals and associated measures are currently at a preliminary design stage and your comments are welcomed to help maximise the benefits and minimise the dis-benefits of these necessary proposals.

Comments on the proposals and other representations, specifying the grounds on which they are made, may be sent in by completing the online questionnaire, via email or in writing (quoting ref: CM/12.6.260) to the address below by 11 June 2020. The Council will consider representations received in response and they may be disseminated widely for these purposes and made available to the public.

* Whilst we will endeavour to answer simple queries during the course of this consultation, any more complex questions/issues will be appraised, considered and dealt with as part of the process.

 

Timeline

  • Opened
    10 May 2021 at 09:00
  • Closed
    11 Jun 2021 at 15:00

Details

Contact Name Christian Mauz (Technical Officer - Traffic & Road Safety)
Contact Email Address christian.mauz@oxfordshire.gov.uk
Contact Phone Number 0345 310 1111
Contact Postal Address Oxfordshire County Council
County Hall
New Road
OXFORD
OX1 1ND

Consultation Topic
  • Economy & business
  • Environment & waste
  • Fire & public safety
  • Planning
  • Roads & transport
Target Audience
  • Oxfordshire residents
  • Councillors
  • Businesses
Geographical Area
  • Kidlington and Yarnton