Please supply details of the current traffic light phasing at the junction of Chiswick High Road and Sutton Lane North/ Acton Lane. Also include details of when the phasing changed

---

TfL Ref 0816-2021

Thank you for your request received by Transport for London (TfL) on 14 August 2020 asking for information about current traffic light phasing at the junction of Chiswick High Road and Sutton Lane North/ Acton Lane.

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 the information you require.

The traffic lights at the junction of Chiswick High Road / Sutton Lane North / Acton Lane are controlled by a system that automatically adjusts the balance of green signal time for each approach.  Detectors in the road surface inform the system, which then optimises the traffic signals according to the amount of vehicles approaching from each direction.  As detailed below, green signal times also change depending on the action of pedestrians and certain traffic movements. Therefore, the amount of green signal time that each approach receives is constantly adjusting, so the figures given below are averages, based upon our automated records from 01 August 2020 to 18 August 2020.

The sequence of movements at this junction is:

1. Eastbound and Westbound together
2. Northbound and Southbound together
3. Southbound only (depending on demand from southbound right turning vehicles)
4. Pedestrian crossings (depending on push button demand)

The southbound only movement is demand dependent, so will only trigger when there is a sufficient amount of right turning vehicles waiting in the junction.  When demanded, this green signal phase runs for a fixed duration.  When there is not sufficient demand for right turning vehicles, then the northbound and southbound phases will continue to run together.

The pedestrian movement is demand dependent, so will only trigger if people use the push button to request the green man signal.  When the green man is not requested, the additional green signal time is given to the Eastbound and Westbound traffic movements.

These traffic signals can also be remotely operated by the team in the Network Management Control Centre, who may make temporary changes to assist traffic in response to challenging network conditions.  These changes can be made at any time and may involve increases or decreases to green durations for any approach.  After the situation has passed, the traffic signals are returned to normal.

The figures quoted below are averages, as explained above.

AM Peak

Eastbound and Westbound = 16 seconds  (minimum possible is 11 seconds)

Northbound and Southbound = 14 seconds (minimum possible is 9 seconds)

Southbound only = 10 seconds

Inter Peak

Eastbound and Westbound = 15 seconds (minimum possible is 11 seconds)

Northbound and Southbound = 15 seconds (minimum possible is 9 seconds)

Southbound only = 10 seconds

PM Peak

Eastbound and Westbound = 14 seconds (minimum possible is 11 seconds)

Northbound and Southbound = 17 seconds (minimum possible is 9 seconds)

Southbound only = 9 seconds

Since mid-March, the automatic green duration adjustments have fluctuated significantly as a result of reduced traffic flows, due to the CoViD Pandemic .  The most recent consistent change made to the traffic signals was on 27 May 2020.  On this date, the maximum overall amount of green signal time available to all approaches was reduced from 56 seconds to 40 seconds.  As with the current timings listed above, the amount of green signal time that each approach received before this date will have been automatically adjusting minute to minute, according to the conditions on street.

The impact of current circumstances on TfL’s resources means we are not able to answer FOI requests readily and we ask that you please do not make a request to us at present.

Answering FOI requests will require the use of limited resources and the attention of staff who could be supporting other essential activity. In any event, please note that our response time will be affected by the current situation.

If this is not the information you are looking for, or if you are unable to access it for any reason, please do not hesitate to contact me.

Please see the attached information sheet for details of your right to appeal as well as information on copyright and what to do if you would like to re-use any of the information we have disclosed.

Yours sincerely

Sara Thomas

FOI Case Management Team

General Counsel

Transport for London

Back to top

---