Request ID: FOI-0897-2324 Date published: 20 July 2023
You asked
F/on from IRV-020
Your email kindly mentioned giving me the "technical notes which outlines the parameters that have changed" and "objective forms" that further explain the "heavy queuing". If I can apply to see those, I would be very grateful. It sounds like you may have them easily at your disposal.
Then, you mentioned "green time graphs" and a need for an "exact location". The only traffic light I'm interested in is the one outside Marks & Spencers on King Street in Hammersmith (so the first light any traffic encounters as they turn off the Hammersmith gyratory. I'm intrigued to see how timings on this light have been affected by the removal of a bus lane to create a cycle lane where a bus now stops at a nearby bus stop and all the traffic backs up on to the gyratory (roundabout). In another FoI, it emerged that the traffic light green times had to be shortened to keep traffic moving.
We answered
Our ref: FOI-0897-2324/GH
Thank you for your request received by Transport for London (TfL) on 22 June 2023 asking for information about traffic signals.
Your request has been considered under the requirements of the Freedom of Information Act 2000 and our information access policy. I can confirm that we do hold the information you require.
Please find attached the technical notes and the objective forms for the signal reviews on Hammersmith Gyratory and Chiswick High Road following the implementation of the Cycleway 9 scheme
Also, provided is the graph showing vehicle green time for the pedestrian crossing outside Marks and Spencer’s on Kings Street. The yellow line on the graph shows minimum average length of time the traffic light stays green for each cycle. The traffic movement would receive more green time when there is no pedestrian demand to use the crossing, as the green light for traffic will continue to run until there is any pedestrian demand to cross. The data shown starts on 1st Jan 2019 and goes up to 1st June 2023.
During this period (highlighted in the graph as “BT line fault issue”) the operation of the pedestrian crossing was affected by a fault with a BT line cable connecting the pedestrian crossing to the main controller. During the time of the fault the operation of the pedestrian crossing changed so that it was controlled locally using background timings. The area of the graph where it is highlighted with BT line fault issue was a period of time where we weren’t collecting stage length data from the site as it was not connected to our central computer system. When the site dropped offline in late 2021 the traffic stage would receive a minimum of 20 seconds of green time per cycle, with the green light continuing for longer if there was no pedestrian demand. From 31st January 2022 when the crossing was still offline the traffic stage would have been receiving a minimum of 30 seconds of green time per cycle, with the green light continuing for longer if there was no pedestrian demand. From April 2023 the site came back onto the Urban Traffic Control system so the line shown in the graph is an accurate average for the green time running since then.
If this is not the information you are looking for, or if you are unable to access it for some reason, please do not hesitate to contact me.
If you are not satisfied with this response please see the attached information sheet for details of your right to appeal.
Yours sincerely
Graham Hurt FOI Case Officer FOI Case Management Team General Counsel Transport for London
