The US device is close to production and can distinguish between phones that are calling, texting or using their mobile internet connection.
Texting while driving can be just as dangerous as travelling over the speed limit but except in the most obvious case it can be difficult for law enforcement to spot offenders.
However a new gadget dubbed the ‘texting gun’ could join the speed radar and breathalyser as key weapon in the fight for road safety.
The device has been developed by US company ComSonics, who claim that the device can detect the distinct radio frequencies emitted by a phone sending a text.
In America texting behind the wheel has overtaken drink driving as the biggest killer of teenagers, with more than 3,000 young people killed every year from crashes caused by distracted drivers.
Virginia-based ComSonics say that their ‘texting gun’ could help curb this problem, using technology based on the devices used by TV repairmen to locate damaged TV cables by ‘leaked’ transmissions.
Despite privacy concerns the Sniffer Sleuth was unable to intercept any of the content of texts being sent – although it was able to distinguish between the frequencies used for texting, calling and mobile data.
Although the old style of SMS messaging may still be fairly popular, younger mobile users tend to prefer apps that send messages using an internet connection.
Even with the Sniffer Sleuth this activity would be indistinguishable from the data connection used for safer activities such as playing music or providing driving directions.
