Thames Valley Police will be among the first in the country to use a new device which can detect when motorists are using their mobile phones while driving.
The technology can determine how many cars on a stretch of road have phones being used without hands-free kits.
Hampshire Police will also trial the device.
A spokesman for the two forces said: "The technology can detect when Bluetooth is being used but cannot detect if a passenger is using the phone, but the sign will still be activated reminding motorists of the distraction of a mobile phone whilst driving."
The campaign is being supported by Kate Goldsmith, from Bedfordshire, who lost her daughter Aimee Goldsmith after a lorry driver crashed into the car she was a passenger in while he was using his mobile phone to change music whilst driving.
The 11-year-old was killed along with her stepbrothers Josh Houghton, aged 11, Ethan Houghton, aged 13, and the brothers' mother Tracey Houghton, aged 45.
Ms Goldsmith said: "I am supporting this campaign and welcome any technology which can assist in educating people and stop them from using their mobile phones whilst driving.
"My daughter's death was completely avoidable.
"Please don't use your mobile phone whilst driving, it's not worth the risk."