Emergency vehicles in Denver are being installed with ground-shaking subwoofers as standard in a bid to shift distracted motorists who block their way to the hospital.
Flashing lights and loud sirens are no longer keeping drivers out of the path of ambulances, Denver Health EMS said, so the service fitted its vehicles with 100/200-watt siren amplifiers to give off warning vibrations.
"They vibrate the entire ground," Scott Bookman, chief paramedic for Denver Health EMS, told the Denver Post. "People can feel it throughout their car. It's pretty neat."
Bookman said that motorists are increasingly failing to let emergency vehicles pass for several reasons -- some simply freeze in panic, while modern cars are often designed to block out sound and drivers get distracted by gadgets.
He said that after testing the booming sirens in 12 vehicles for 18 months, "people seem to be more aware now."
The service, which has a nine-minute target for responding to call-outs, is making the subwoofers standard issue for all new vehicles.
Denver police ticket more than 70 drivers a year who fail to yield to an emergency vehicle, but officers must witness the act in order to issue a ticket.