Broken-down vehicle alerts on M4 smart motorway were not working properly in days leading up to fatal crash that killed grandmother, court hears

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Published: 18:02, 16 February 2026 | Updated: 20:09, 16 February 2026

Alerts designed to warn drivers of broken-down vehicles on the M4 smart motorway [2] were not working properly for days before a fatal crash that killed a grandmother, a court has heard.

An unresolved technical failure on the motorway's IT network meant warnings were not being passed on to operators in the days leading up to the collision, jurors were told.

The fault was detected by the system on March 2, 2022, and automatically generated tickets, but these were sent to the wrong National Highways team and given an incorrect priority level of a 'seven-day resolution'.

As a result, the alert system had been malfunctioning for five days when Barry O'Sullivan, 45, drove his grey Ford Transit Connect into the back of a Nissan Micra that had come to a halt in the fast lane of the motorway on March 7, 2022.

The collision happened on the M4 westbound between junctions 11 and 12 in Berkshire, causing both vehicles to be propelled forward, with the Nissan bursting into flames.

Pulvinder Dhillon, who was travelling as a passenger in her daughter's Nissan Micra, suffered fatal injuries.

The trial at Reading Crown Court has previously heard that the smart motorway system 'wasn't showing messages about any obstructions in the road ahead' on the morning of the crash.

Pulvinder Dhillon, 68, was a passenger in her daughter's Nissan Micra when it stopped in a live lane of traffic on a section of the M4 with no hard shoulder in March 2022.

She died at the scene after it was struck by a van

Barry O'Sullivan (pictured at Reading Crown Court on February 2) denies causing death by careless driving

Jurors were told on Monday that alerts from stopped vehicle detection (SVD) radars on the M4 between junctions 8/9 and 12 had not been communicated since March 2, 2022, because of the technical failure.

Ian Bridge, representing O'Sullivan, read extracts from a National Highways investigation report commissioned after the fatal collision.

'The SVD was available between the 2nd of March to the 7th of March 2022, but the communication failure meant alerts were not presented to the regional operations centre operators,' the report said.

The report also suggested a broken-down vehicle had been detected by radars on the day of the crash but 'did not meet the waiting criteria to raise an alert'.

'The accuracy or completeness of this entry has been unable to be checked by suitably qualified person with access to the records,' it added.

Jurors have previously been told it took two hours and 29 minutes to fix the problem with the smart motorway system after the collision.

The first call from a member of the public to Thames Valley Police reporting the stranded vehicle was made at 8.37am on the day of the crash.

The highways authority was informed shortly after 8.41am - around four minutes and 12 seconds after the police call began.

The Nissan had been stationary in the fast lane for six minutes before the collision, the court has heard.

The collision happened on the M4 westbound between junctions 11 and 12 in Berkshire (above)

O'Sullivan was driving his Ford van at between about 74mph and 80mph in the fast lane of the M4 westbound in the five seconds before the impact.

Giving evidence, the defendant told jurors the crash 'wouldn't have happened' if he had been 'forewarned'.

He said that when he first saw the vehicle in the fast lane, he 'didn't perceive it to be a hazard' and 'perceived it to be moving'.

He told the court: 'All of a sudden I realised I'm gaining on this vehicle really fast, then I went to slam the brakes on and then before I knew it the collision happened.'

O'Sullivan, of Wixams near Bedford, has pleaded not guilty to one count of causing death by careless driving.

The trial continues.

References

^ LETTICE BROMOVSKY, NEWS REPORTER (www.dailymail.co.uk)
^ smart motorway (www.dailymail.co.uk)