Getting a driver's attention today can be nearly impossible. Loud music, cell phones, fans blowing and maybe even children bickering in the backseat distract today's drivers. With the Rumbler Intersection-Clearing System, Federal Signal makes the nearly impossible, possible.
While the primary siren and warning lights on an emergency vehicle remain critical, the Rumbler attracts attention by being heard — and felt.
"The idea came up that people were cocooning themselves so much inside their vehicles that in some cases, the siren and lights didn't seem to be enough," says Tom Morgan, police market vice president at Federal Signal Corp. Morgan credits Capt. James Wells of the Florida Highway Patrol for coming up with the original idea that a supplemental warning system was needed to get people to pay more attention to emergency vehicles.
The Rumbler attracts attention by creating a vibration. The lower frequency tones of the Rumbler penetrate and shake solid materials, allowing drivers and nearby pedestrians to feel the sound waves (and possibly see the effects on a shaking rearview mirror).
After the Rumbler is activated, people have a tendency to look up and check their rearview mirror to see what's causing the vibration, Morgan describes. Once the Rumbler has a motorist's attention, he or she should see the warning lights of the emergency vehicle behind them. The driver becomes aware a regular siren was going off (though the individual's ears were receiving the audible siren, his or her brain wasn't quite processing it with all the other distractions going on in the vehicle) and pulls over.
Less than two years old, the Rumbler is currently used by about 60 law enforcement agencies. The Rumbler is most common in densely populated metropolitan areas on the East Coast. Morgan points out the Rumbler is sometimes perceived as more effective in larger communities than smaller communities.
"The communities that have the densest traffic are really seeing value," he says.
Intersections are particularly dangerous and the Rumbler helps focus motorists' attention on the police car. On the highway, law enforcement officers use the Rumbler in heavier traffic, when an officer needs to clear the lane in front of him.
Although a supplemental warning system is an extra cost to law enforcement agencies, Morgan points out that by helping officers avoid traffic crashes, it helps them save money, and better protects citizens and officers alike.
"I think the main benefit is improved safety," he emphasizes. "Particularly in high-risk situations, such as intersections or heavy highway traffic."Rumbler reactions
Within about 200 feet in most cases, the Rumbler will at least cause a driver to look up, but response to the Rumbler can differ. Morgan has observed different reactions during demonstrations. In one case, a person really felt it while the person next to him felt it, but not as much.
"Different people do respond in different ways to that lower frequency," Morgan says.
People attending demonstrations have said they were expecting the Rumbler to really jolt them. However, Morgan explains that a jolt is not the intended effect, but rather the Rumbler is meant to be less shocking. The subtle vibration should cause motorists to look up and pay attention.
Some people say the sound emitted is annoying but most police officers consider that effect to be positive, he says. Even if it annoyed motorists, the vibration captured their attention.
Other reactions characterized the Rumbler as louder than a regular siren, which Morgan refutes, explaining that the Rumbler actually operates at about 10 dB less than the traditional, primary siren.
"I think some people expect it to be like somebody pulling up to them with a boom box going so loud that they see everything start to vibrate around them," he says. "Although it operates on the same kind of principle at the lower frequency, it's more subtle than that."