SWAMPSCOTT – A new device in two of the patrol cars in town has the potential to rattle teeth and shake drivers out of their complacency.Police Chief Ronald Madigan said the two cruisers the department has purchased are equipped with “The Rumbler,” a new technology from Federal Signal Corporation.”One of the cruisers hit the street earlier this month,” he said. “We’re going to roll out the other cruiser soon.”Madigan said The Rumbler is a high-tech device that is designed to complement the flashing lights and sirens when vehicles are not moving over to allow the police vehicles to pass.”It is really designed to contend with issues involving cars that are soundproof or people playing music too loud,” he said. “It’s to be used judiciously when motorists are less than responsive to emergency vehicles that are trying to get past.”Madigan said The Rumbler was an option the department ordered in its two new vehicles and the device emits a 10-second audible warning that can actually be felt by drivers.”It’s impossible to ignore,” he said. “It emits a low frequency vibration that is felt by drivers. I’ve been told it can rattle your teeth and people feel a slight tremor in their body.”Madigan said the device would only be used when the police cars are responding to an emergency and motorists aren’t moving out of the way.”It wouldn’t be used all the time,” he said. “It would only be utilized when vehicles won’t move out of the way. Drivers can actually feel this and it would be useful during daylight hours when the lights aren’t as visible and drivers aren’t responding to the sirens.”Madigan said soundproofing in some of the newer vehicles, drivers wearing headphones and loud car stereos are just a few of the factors that make drivers oblivious to sirens around them.”We’ve all seen the cars with music blasting you can hear outside the car,” he said. “The idea is to get safely and quickly around other vehicles when responding to emergencies when vehicles aren’t responding to lights and sirens.”North Reading Police Chief Edward Nolan said most of the police cars there are equipped with the device.”We were part of the beta tests for this device in this area,” he said. “So we’ve had it for at least two years. It’s an audio device that is part of the siren package. It sends out a very low frequency sound like a bass radio that drivers can feel. It’s a very effective tool and my officers (believe) that when they employ it people are more apt to take notice.”