TfL Ref: FOI-0684-2223
Thank you for your request received by Transport for London (TfL) on 21 June 2022.
Your request has been considered in accordance with the requirements of the Freedom of Information Act and our information access policy. I can confirm that we hold some of the information you require. You asked:
As part of the 'temporary' installation of CS9, a new bus gate was installed on Chiswick High Road in the eastbound direction before the junction of Acton Lane. Please provide the cost of installing the bus gate and also the estimated cost for removing it, given that the original approval was temporary in nature. Please confirm if budget has been reserved for its removal.
The total cost of delivering the temporary elements of CS9 was £600k but these costs are not broken down by feature, such as the bus gate, due to the many integral parts and the dependencies on other design elements which make up the whole project cost. The London Streetspace Programme held a budget allocation to make schemes permanent, make changes or remove them and this was held at programme level. The cost of removing the bus gate as a standalone element of the scheme was not estimated at the time, but should this have been required an estimate for this and any other required work would have been compiled and funded from the programme level allocation for changes or removal.
The traffic light phasing for CHR traffic at the junction of Acton Lane/ Sutton Lane North have changed since the bus gate was installed. Please supply the length of the average peak time green phase for CHR traffic at this junction pre COVID. Please then also supply the length of the average peak time green phase for this junction over the last 6-12 months, or whatever recent timeframe is readily available.
Traffic stage lengths for the Chiswick High Road with Acton Lane signals have changes since January 2019. The attached graphs in a document entitled “Chiswick High Road Acton Lane Signal timings” show total stage length which includes both the traffic green time plus the intergreen (the safety critical timing that must operate between each conflicting traffic phase).
The bus gate signal timings are set up to be linked to the green time provided to Chiswick High Road eastbound at the Acton Lane signals. We operate the bus gate in two scenarios depending on the level of congestion detected between Heathfield Terrace and Acton Lane. The bus gate was included in the temporary scheme to mitigate the loss of eastbound bus lane when compared to the permanent scheme. In a situation where there is no congestion, the bus gate receives 12 additional seconds above the Chiswick High Road eastbound movement, which allows all traffic to clear the stop line. When congestion is detection, the bus gate green time is reduced by 9 seconds, which has the effect of holding traffic away from the section of Cycleway 9 scheme that does not have a bus lane.
The bus gate was originally installed in November 2020, however the detection equipment was not introduced to July 2021. The graphs show that since the introduction of the bus gate, Sutton Lane North has generally received more green time than pre-scheme and pre-pandemic. It also shows Chiswick High Road eastbound has been receiving less green time as part of our strategy to protect buses through the scheme and during the recent works between Chiswick Lane and Goldhawk Road. Since Mid-May 2022, there has been a reduction in green time for Sutton Lane northbound to pre-pandemic levels and an increase for the Acton Lane southbound only movement.
It has always been our intention to review the signal timings post construction. This work has commenced and as part of this work we have found some faulty detectors which is causing the reduction in green time for Sutton Lane North. Part of the review process is to find and rectify these faults and we will implement a temporary fix to return the green time to levels that existed before the detector went faulty.
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Yours sincerely
Eva Hextall
FOI Case Management Team
General Counsel
Transport for London
