The Howler is being used by BASICS Hampshire, a charity made up of 20 volunteer medics who attend about 750 road traffic accidents every year.
The Howler sends out low bass sound that makes the car in front "shake".
Dr Rob Dawes, a volunteer doctor whose full-time job is as an hospital anaesthetist and military doctor, said people get out of the way quicker when the device is used.
He said: "The main problem is on the motorways where people can't hear the sirens or see you, because often they either don't look in the mirrors or they've got the radio on quite loud.
"What this new siren aims to do is, because they can't see you and they can't hear you, we hope that they'll be able to feel you."