“Disco effect” on-off street light issue could be caused by software fault

Photo of a street lit by LED lighting.
LED lighting in use on a street in South Gloucestershire.

An unexplained problem with street lighting in South Gloucestershire is causing hundreds of lamps to repeatedly turn on and off at frequent intervals during the night and day.

Reports of the erratic switching behaviour first emerged in the early hours of today (Wednesday 13th January 2021) with one Bradley Stoke resident posting in a Facebook group that local street lamps “keep turning on and off in the span of a minute”. Confirmation of similar behaviour elsewhere soon flooded in from across Bradley Stoke, on the A38 in Patchway and in Cheswick Village (Stoke Gifford).

Comments on a post published on the Bradley Stoke Journal’s Facebook page at 8am described similar issues happening in Filton, Lyde Green and Coalpit Heath, with one reader saying the street lights along Badminton Road were “flashing like a bad wedding disco”.

A post made on South Gloucestershire Council’s (SGC’s) StreetCare Facebook page at 9.03am confirmed the issue, saying:

“We are aware of an issue with streetlights turning off and on frequently across the district. Our engineers are looking into this as a matter of urgency. Many thanks for your patience.”

With the lights continuing to blink during daylight hours, when they would normally be off, a further sliver of information came from a local councillor who posted on Facebook at 1.12pm that he had been informed by a council officer that “the problem is not specific to South Gloucestershire and is [also] occurring in other areas of the UK.”

Research by the Journal revealed that the Manchester Evening News had reported that a similar issue with flickering street lights had surfaced in Salford over the course of Monday night to Tuesday morning (12th January 2021).

The paper reported that Salford City Council had explained that the issue is most likely to have been “caused by a software problem in the GPS device [within each lamp] that calculates sunrise and sunset times”.

The majority of installed street lights use a photocell rather than a GPS device and so were unaffected, a senior council member added.

Door Express South West: Internal door specialist serving Bristol and South Gloucestershire.

The reference to GPS-controlled units may be significant as South Gloucestershire Council installed this type of device in the first three years of its LED street lighting rollout beginning in January 2014, before switching to photocell-controlled units for installations made after 1st April 2017. During the first phase of the rollout, when GPS-controlled units were used, they were first installed along all main roads across South Gloucestershire and then in selected built-up areas, starting with Charfield and reaching Bradley Stoke in December 2015. The programme is ongoing and will should finally complete with Dodington and Yate in 2023/24.

LED streetlight lantern in Bradley Stoke, Bristol.
An LED streetlight lantern in Bradley Stoke.

Concerned residents have been contacting SGC throughout the day, by phone and via social media. One Journal reader reported this afternoon on our Facebook page:

“Just rang South Glos Council. Was told it’s happening all over the country. Apparently South Glos says it’s a software problem which they are not responsible for. There is no timescale for its resolution. It’s a bit like a sound-to-light system in our road.”

Should the issue be confirmed as a non-transient software problem which requires a fix to be made within every installed light unit, the cost and time implications could be immense, not to mention the ongoing road safety issues.

Late this afternoon, the Journal received the following brief statement from SGC:

“We can confirm that the problem which is causing some of our street lights to turn off and on again, is also occurring in other areas of the UK. We are currently investigating the matter and are in contact with the company that manages the infrastructure to resolve the issue.”

Related link: LED street lighting (SGC)

Addendum: Selected Twitter posts

Added 14th January 2021

Update: Software issue “resolved”

Added 15th January 2021.

Statement issued by Bridgend County Borough Council on 14th January 2021:

A software issue which saw more than 7,000 local streetlights switching themselves on and off across Bridgend County Borough has been resolved.

The UK-wide problem, which was also reported in areas such as Manchester and Bristol, began on the evening of 13th January and went on throughout the early hours until dawn on 14th January.

It is believed to have only affected street lights which use global positioning technology to calculate what time the sun rises and sets.

While these lights are in use within communities located all across the county borough, the rest of the area’s 20,000 streetlights, which are capable of detecting low light levels, continued to work as normal.

The problem was resolved after Bridgend County Borough Council’s Street Lighting team contacted the manufacturers of the affected street lights, who were able to reset them.

Councillor Richard Young, Cabinet Member for Communities, said: “I’m pleased that this issue was resolved quickly. We have requested a full explanation for why it took place along with reassurances that it will not happen again.”

“The vast majority of our street lights use photocells to determine when they need to switch on and off, but around a third carry out this same function using global positioning technology, and these were the ones affected by the glitch.”

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