traffic signals at the junction of the A41 and The Burroughs
Request ID: FOI-0889-2425 Date published: 03 July 2024
You asked
Dear Sirs
Please could you provide the following information under FoI.
The questions relate to the traffic signals at the junction of the A41 and The Burroughs, specifically those for road traffic travelling through this junction arriving on Watford Way from the north west and continuing on Watford Way towards the south east. They are the signals visible here:
https://www.google.co.uk/maps/@51.5863019,-0.2310309,3a,24.9y,136.89h,87.78t/data=!3m6!1e1!3m4!1s3x-bpLkyDEIgeHCoovmP5g!2e0!7i16384!8i8192?entry=ttu
For the period 18 April 2024 to 16 May 2024:
• what was the programmed duration for the amber phase, i.e. before red, at these signals (including, if applicable, any changes made to this programmed duration, with the date/time of the change)?
• what checks, if any, were made, or what other means of verification were used, to ascertain (a) whether the actual duration of the amber phase was as programmed, and (b) whether any or all of the amber lamps was working correctly or at all?
• what reports, if any, of faults at these lights did you receive, and what was the nature of the reported fault?
• what maintenance or adjustments were made at these lights?
We answered
TfL Ref: 0889-2425
Thank you for your request received by Transport for London (TfL) on 18 June 2024 asking for information about the traffic signals at the junction of the A41 and The Burroughs.
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.
You specifically asked: Please could you provide the following information under FoI.
The questions relate to the traffic signals at the junction of the A41 and The Burroughs, specifically those for road traffic travelling through this junction arriving on Watford Way from the north west and continuing on Watford Way towards the south east. They are the signals visible here:
what was the programmed duration for the amber phase, i.e. before red, at these signals (including, if applicable, any changes made to this programmed duration, with the date/time of the change)?
what checks, if any, were made, or what other means of verification were used, to ascertain (a) whether the actual duration of the amber phase was as programmed, and (b) whether any or all of the amber lamps was working correctly or at all?
what reports, if any, of faults at these lights did you receive, and what was the nature of the reported fault?
what maintenance or adjustments were made at these lights?
Response:
what was the programmed duration for the amber phase, i.e. before red, at these signals (including, if applicable, any changes made to this programmed duration, with the date/time of the change)?
The Amber Period on all traffic signal is a fixed duration of 3 seconds. This is defined in statuary Law in the “Traffic Signs Regulations and General Directions 201 (TSRGD 2016). This period is hard wired into all traffic signal controllers and cannot be changed at all. This applies to all traffic signal controllers across the United Kingdom.
what checks, if any, were made, or what other means of verification were used, to ascertain (a) whether the actual duration of the amber phase was as programmed, and (b) whether any or all of the amber lamps was working correctly or at all?
This is checked at multiple points:
All types of Traffic signal controllers which are used to control signalised junctions/roundabouts need to be certified by the National Body, called TOPAS, to the specification “TOPAS 2500., Specification for Traffic Signal Controller”. Part of the testing regime to ensure that any new controller meet this specification is that the Amber period is a fixed 3 seconds.
The duration of this is also checked during the Factory Acceptance Check carried out by the traffic signal contractor on the actual controller used at each specific location and its operational configuration.
When the site works have been completed, the workings of the controller and its configuration are also checked on site before this is taken over into maintenance by TfL.
If there is any fault regarding the appearance or duration of the Amber Period, the controller will register a “Major fault”. This is defined in the British Standards BS EN 12675, in TSRGD 2016 and in TOPAS 2500. A major fault will result in the traffic signal controller “switching off”. The fault will be registered in the controller fault log and reported to TfL’s London Streets Traffic Control Centre.
In summary, the duration of the Amber period is 3 seconds, it is defined in Law, and cannot change. This is checked and verified, both in the equipment manufacturing and on street. If the duration is violated in any way, the traffic signal controller will report a fault and switch itself off.
what reports, if any, of faults at these lights did you receive, and what was the nature of the reported fault?
what maintenance or adjustments were made at these lights?
For questions 3 & 4, there is a map reference below to confirm location being answered.
There were two maintenance attendances between the dates given (18 April 2024 to 16 May 2024)
Scheduled lamp maintenance where all lamps are replaced and the signals are cleaned. This was carried out on 22 April 2024.
A fault reported by our computer monitoring system that a red lamp had failed.
This was automatically reported at 05:59 on 24 April 2024.
Our contractor attended between 23:25 and 23:55 on 24 April 2024 and replaced a failed red lamp for The Burroughs as shown on the following diagram.
The log within the controller shows the fault was cleared at 23:42 on 24 April 2024.
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
