Police across Hampshire and the Thames Valley have become the first in the country to use groundbreaking technology which can tell if a driver is using their mobile phone behind the wheel.
people killed in the Thames Valley since 2014 as a result of drivers using phones behind the wheel
Detector units are being installed in accident hotspots, to deter motorists from using their mobiles.
The technology can detect how many cars on a particular stretch of road are using their phones without hands free.
It works by detecting if there is an active 2G, 3G or 4G signal in operation.
A sign will flash to tell a driver to stop using their mobile.
However the detectors will not be able to tell if it is a driver or passenger using the phone.
Research shows that you are four times more likely to be involved in a crash if you use your phone while driving.
people killed in Hampshire since 2014 as a result of drivers using phones behind the wheel
The detector will be located on the A34 in Oxfordshire but will be posted at different locations throughout the Thames Valley and Hampshire.
Interviewee: PC Liz Johnson, Thames Valley Police
It's not an enforcement tool, it's purely an educational tool. It's a reminder for people not to use their mobile phone whilst driving. It might not be for you, it might be for the car behind you, but somebody around you is using their mobile phone and it will light up to remind them to get off the phone."
A mother who's daughter died in a collision involving a lorry driver using his phone has welcomed the move, continuing her plea to urge drivers to stop using their mobiles behind the wheel.
Kate Goldsmith's 11-year-old daughter Aimee was killed on the A34 in August 2016 when a lorry ploughed into the back of two stationary cars.
The lorry driver had been using his mobile phone to change music while driving.
In the collision, Aimee's stepbrothers Josh Houghton, 11, Ethan Houghton, 13 and their mum Tracey Houghton, 45, also died.
Kate's 13-year-old son Jake survived, but she says he was left "traumatised by the crash and deaths of Aimee and his best friend".
The driver, 31-year-old Tomasz Korker is currently serving ten years in prison.
He was sentenced at Reading Crown Court after pleading guilty to four deaths by dangerous driving and a single count of causing serious injury by dangerous driving.
WATCH: Aimee's mother, Kate Goldsmith, speaks to ITV News Meridian