Lights and sirens evolve to clear the way

Pat Gauen
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PATRICK E. GAUEN
ST. LOUIS POST-DISPATCH
04/15/2010

"Stop the truck! Stop the (expletive) truck!"

Something was wrong, in the estimation of Capt. Vince Wright, so driver Gary Ruffin pulled to the curb in the green-and-white Mack then used by the St. Louis Fire Department's Rescue Squad 2.

Wright wriggled out the cab window and sat on the sill while reaching up on the roof, beyond my view from the jumpseat behind him. Then came a deafening blare of air horns, squealing and squalling in various pitches until Wright adjusted the reeds to a tone that suited him.

"It's just that time of year," firefighter Bob Wangler told me from the next seat over. "It's a mating call. We're trying to attract another rescue squad.''

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Humor aside, the real issue wasn't attracting anything. It was repelling something: traffic. In several months of riding along years ago to write a story about the squad, I knew those horns might be our best defense against a collision. They were more piercing than the siren and more demanding than the red and white lights.

Clearing drivers out of the way has been a challenge since police and firefighters and medics acquired motor vehicles and began blasting away with hand-crank sirens.

While warning-signal technology has come a long way, countertechnology has come as far. Modern drivers are insulated by tight windows and doors, sound-deadening materials and tinted glass. They're isolated by stereos and cell phones and navigation systems that limit what they hear and see, and distract their attention.

Deaths such as those of St. Louis police Officers David Haynes and Julius Moore, in collisions on calls last month and last year respectively, raise the question of whether there is better protection for emergency workers who care enough to rush to our aid when we're in trouble.

Presuming that no one has invented a way to smell or taste the approach of a police car, the task falls to three usable senses.

— Hearing. This was the first target, from days when sirens were more common than warning lights. Mechanical sirens are loud but also very heavy, and they consume lots of electricity. These days, you seldom hear one except on a firetruck. Electronic sirens may not be quite as loud but are more compact and power-friendly, and offer versatile sounds ("wail" and "yelp" to name two) and a public-address capability. Putting out up to 120 decibels, they operate near the human hearing pain threshold. Going louder would have health and liability implications for first responders and bystanders alike.

— Vision. Incandescent warning lights have flashed, rotated and oscillated for decades. The advent of strobes gave brilliant pops of light, but got duller with age. Now LED lights are the latest thing, with a dazzling effect that seems to stand out better day and night. Pretty much every agency around here uses or is converting to them. Some emergency vehicles also carry flickering whitish lights that activate receivers at a few strategic intersections to give them a green signal.

— Touch. Yep, touch. Those air horns on Wright's rescue truck worked so well because their deep vibrations could be felt as well as heard. Many electronic sirens have synthesized horn sounds. Now, police in New York City have tested and are buying more of a low-frequency siren add-on — trademarked as the Rumbler — that shakes drivers in sync with the audible shriek. (Think of the thumping bass from a car with an annoying megastereo.)

I talked all of it over this week with J.P. Molnar, a performance driving expert and former San Diego city and Nevada state cop who teaches and writes nationally about emergency vehicle operations.

The long-term answer, he figures, would be a mandatory alarm on every vehicle's dashboard, set off by the approach of emergency equipment. "They made air bags standard, and tire pressure monitoring for new cars," he said. "They could do this, too."

Short of that is a reminder that Molnar said he drills into every one of his emergency driving students: "You may think that every second counts, but it can be important to take an extra two seconds, or an extra eight seconds, to get through safely. Remember, you can't help anybody if you don't get there."