CAD Provides Hurricane Relief

A dispatch management system is helping Wilmington, N.C., expedite 911 calls with maximum speed and accuracy.

by / December 31, 1996
As sheriff of New Hanover County, N.C., Joseph McQueen Jr. has seen his share of hurricanes. Commenting on the devastation from last fall's storms, McQueen said, philosophically, "we're known as 'Hurricane Alley.'" But this year was particularly rough; Hurricanes Bertha and Fran, scarcely a month apart, bowled through the county, sending tens of thousands of residents and vacationers fleeing inland. Winds gusting up to 115 miles per hour ripped boats from their moorings and washed them ashore, mangled telephone and power lines, tore away roofs, drove uprooted trees into houses, and sent ashcans flying through the streets like shrapnel.

It was a time when the Command and Control Center in Wilmington needed a dispatch management system to expedite the flood of 911 calls with maximum speed and accuracy. Fortunately, the center had recently installed a new computer-aided dispatch (CAD) system that instantly mapped caller locations and automated much of the time-consuming detail involved in calltaking and dispatching. As a result, calltakers were able to direct appropriate agencies to addresses and scenes throughout the county with greater efficiency than the county's enhanced 911 system allowed.

New Hanover County is situated between Cape Hatteras and Cape Fear, a region of the Atlantic coast that lies directly in the path of hurricanes. One would think with the number of storms plowing through annually, the area would be sparsely populated. Not so. The county's 185 square miles, which include two heavily developed barrier islands, has a population of 141,000.

Under normal conditions, the center handles 1,100 to 1,200 calls a day for the County Sheriff, the Wilmington Police, emergency medical services (EMS) and the Fire Department. During the recent hurricanes, 911 calls flooded into the center at the rate of about 2,000 a day -- a load communications personnel would have been hard-pressed to handle in previous years, not only because of power failures, but because the existing 911 system lacked mapping capabilities and many of the automated features found in advanced CAD systems.

The Intergraph I/CAD system, installed shortly before Hurricane Bertha hit in July, is configured for seven dispatchers, one supervisor, and three calltakers, with a 21-inch monitor at each workstation. Redundancy on the network is provided by two servers.

When a 911 call comes into the center, the calltaker's monitor displays a split-screen of an event window and a map with an arrow at the caller's location. The operator confirms the name, address and telephone number of the caller appearing in the event window, and enters the pertinent information and remarks. After determining the nature of the emergency, the operator -- if he or she is a dispatcher -- radios the appropriate response agency in the county where the call originated.

The I/CAD system can be configured to generate color-coded windows, enabling operators to see at a glance the status of an event. For example, default colors are gray for incoming calls until they are answered, at which time the event window shifts to blue, indicating a new call. A red window indicates a unit responding to that event. When the responding unit arrives, the window shifts to green. In addition, events are prioritized by number, beginning with "0" as the highest priority. If three new events are on the screen, the windows will be blue, with the stack position of each determined by its priority number.

If a caller has a previous event history -- domestic violence, unlawful use of a weapon, or a medical condition -- a Location of Interest (LOI) feature indicates the presence of that information by lighting a special button on the screen. The dispatcher clicks on the button, brings up all the recorded incidents associated with that caller, and advises the responding agency accordingly.

Special Situation is a feature associated with LOI that allows the operator to create a buffer zone around a sensitive address, such as a chemical storage facility, refinery, a suspected drug house, or -- in the case of an apartment complex -- a seriously disabled person living next to someone who has a history of trouble with the law. If a call comes in from any location within the buffer zone, the system automatically retrieves information relating to the sensitive address.

Other mapping features enable the operator to zoom in, zoom out, and temporarily "rope off" sections of streets and highways where major events -- football games, conventions, or road construction -- generate heavy traffic. To determine the fastest route around such closures for emergency response vehicles, the operator has only to enter the location of the vehicle and the desired destination; the system instantly provides directions.

Most 911 calls during hurricanes Bertha and Fran were for injuries and situations directly caused by high winds and flooding, such as downed electrical wires, people trapped by rising waters or in houses partially crushed by felled trees, and people needing to be rescued from homes that had lost roofs. In the aftermath of the storms, 911 calls continued to pour in; people needed to be rescued from collapsed homes, or from trailers piled on top of each other. Some were in shock, wandering around looking for houses that had completely disappeared. One woman was reported floating on a mattress in the middle of a marsh with no idea how she got there.

According to Communications Supervisor Mary Antly, the main advantage of the CAD system is speed. "We purchased the original 911 system years ago. It gave you a number when the phone rang. For us, that was fantastic. Before then, we didn't even have that. Later, we bought the enhanced 911 system, and that enabled us to get the name and address of the caller. The mapping capability in the CAD system has shortened our response time."

"The map automatically shows us where the call is coming from," added Brenda Hewlett, 911 coordinator. "That enables us to direct any agency we dispatch -- no more guessing. We can tell them exactly how to get there."

As with all 911 CAD response systems, map maintenance is an ongoing requirement. Some changes are permanent, others temporary. Population growth, street closures, felled trees, newly created one-way streets
or dead ends, holiday traffic routing -- all require continual updating of the base map.

Auxiliary power systems with backups played an equally important role in keeping the Wilmington Command and Control Center online, said Sheriff McQueen. "In the past, when we had something like this, 90 percent of the time we got knocked off the air. This is the first time in my 27 years in law enforcement that the communication system didn't go down during a hurricane." Reflecting on how the new CAD system performed under countywide emergency conditions, McQueen added, "if we hadn't had this system, we might not have been able to handle the number of calls that did come in during the storms."

Bill McGarigle is a freelance science and technology writer, e-mail: < bmcgari@ >.