‘120km/h to zero in seconds’: Phantom car-braking on motorway near Lyon

A motorist whose car braked suddenly at 120km/h on a motorway near Lyon is calling for urgent recognition of the risks posed by automatic braking systems in modern vehicles.

Joanna Peyrache was driving her Peugeot 208 on the A40 in April when, without warning, the car slowed violently to a standstill. 

The vehicle behind collided with hers, leaving both cars badly damaged and several people injured.

“It was a clear day, it was not raining, no cars were ahead or alongside me,” Ms Peyrache told The Connexion. 

“Over three seconds my car lost speed - I immediately knew what was happening. These automatic braking systems slow vehicles down faster than a driver could. 

“Fortunately there were no serious injuries but the outcome could have been far worse.”

Police requested a technical appraisal, but the prosecutor’s office declined. 

“My insurance company was only really interested in the fact another car hit mine – so it was the other driver’s insurance that had to pay,” she said. 

“The gendarmerie asked for an expert opinion but because there were not any deaths this did not happen.”

Hundreds of testimonies gathered

Frustrated by the lack of interest from the authorities, Ms Peyrache appealed for other drivers to share their experiences of freinage fantôme or phantom braking.

“So far I have had over 600 responses – a lot of them from English speakers – but I have not had time to read them all,” she said. “I suspect the problem is much more widespread. There are probably many thousands affected.”

She added: “There are so many different models, brands and systems involved that there must be many causes behind this. A clear common factor is that they are all quite recent vehicles. 

“These systems can be affected by so many variables. If you change the windscreen, or even suffer a minor jolt, it can make them malfunction. But manufacturers are not forthcoming with information.”

Ms Peyrache is now considering a class action lawsuit against manufacturers. 

“I experienced this accident first-hand and it concerns me to think that other cars can do this, potentially causing deaths, and that I did nothing to prevent it,” she said.

If you have been affected you can send your testimony to Ms Peyrache via incident.freinage@gmail.com. 

The reality of the dangerous phenomenon was brought home earlier this year in another case when a passenger was killed after a car braked suddenly on a motorway. The driver was later convicted of involuntary manslaughter.

In response to the high number of testimonies gathered by Ms Peyrache, the Ministry of Transport announced an inquiry into the issue.

The inquiry, delegated to the service de surveillance du marché des véhicules et des moteurs (the vehicle and engine market surveillance service) will question manufacturers and conduct road tests in order to determine whether the phenomenon represents systemic faults or isolated errors.

Automatic braking systems mandatory

Automatic emergency braking has been mandatory on new vehicles sold in the EU since July 2024. It uses sensors, cameras or radar to detect hazards and apply braking if drivers fail to react.

When asked about the issue, vehicle manufacturer Stellantis – which produces vehicles under marques including Peugeot, Citroën, Alfa Romeo, and Vauxhall – said the system is in widespread usage.

“The emergency braking system is activated when the driver fails to see or identify an obstacle or hazard. It is designed, approved, and functions solely for that purpose,” it said.

However, manufacturers acknowledge that so-called “false positives” can occur, with systems mistaking debris, reflections or gantries for genuine obstacles.

Drivers who believe their car is affected are advised to have the system checked. Sensitivity settings can often be reduced or deactivated via dashboard controls until inspected by a mechanic.