Can GPS help prevent another missing child?

But before getting into the technology, here are some important statistics to put this problem into context.

Stranger abduction is rare
A 2002 study commissioned by the U.S. Department of Justice found that, in one year, 797,500 children were reported missing. That's a lot, but most of those weren't abducted. Of those, 203,900 were family abductions, which means the abductor was related to the child, often a noncustodial parent. Some 58,200 were "nonfamily abductions," but that doesn't necessarily mean strangers were responsible. And 115 children, a tiny fraction of those reported missing, were victims of what the National Center for Missing & Exploited Children (NCMEC) calls "stereotypical kidnapping," which involves "someone child does not know or someone of slight acquaintance, who holds the child overnight, transports the child 50 miles or more, kills the child, demands ransom, or intends to keep the child permanently."

(Disclosure: I serve as an unpaid member of NCMEC's board of directors.)

The potential loss of 115 children a year is a national tragedy, but to put it into perspective, there are 74 million children and teens in America; the odds of it happening are about 1 in 644,000, or about the same risk as being struck by lightning.

Still, it does happen and just because most abductions are carried out by family members or acquaintances doesn't mean that they're not potentially tragic. But it does mean that "stranger danger" is not the biggest threat to our children. In fact, because so many children are exploited by acquaintances and family members, NCMEC has stopped using that term and now refers to it as a "misguided message," because "children don't get it, adults don't practice it (and) it doesn't go far enough in protecting children from potential danger." Plus, when a child is in trouble, sometimes their protector can be a stranger such as a police officer, a mall security guard, or a passerby.

Reasons for concern
Having said, this, there is still a logical reason for parents and guardians to consider equipping their children with a device that can help locate them in an emergency. For one thing, these devices can bring peace of mind. Parents worry about their kids for a lot of reasons beyond being taken by a stranger. Have they wandered off? Did they get into an accident? Could they be lost? And it's not just little kids we worry about. Parents of teenagers are rightfully concerned when they're kids are away from home, especially if they're riding or driving in cars. To be honest, my kids are now in their 20s and I still worry about them.

Technologies
There are various technologies that can help protect children ranging from devices that send out a local alarm that can be heard from a couple of hundred feet away to very sophisticated dedicated GPS tracking devices.

It won't locate your kid or transmit a signal, but the AmberWatch (about $23) is a wristwatch that puts out a 115-decibel signal that, according to its manufacturer, can be heard up to 100 yards away. The alarm is activated by the child by pushing both buttons on either side of the device. It's actually a real watch with time, date, and stopwatch functions and comes in pink and blue. A search for child locator alarm systems will find plenty of similar products.

These products can be useful for finding a child who was wandered off in a mall or perhaps on a trail, as long as the child knows to sound the alarm before they have gone too far. They could play a roll in help to thwart an abduction if the child activates the alarm before the abductor gets them into a car or remote location. But screaming often accomplishes the same goal, which is why NCMEC advises parents to instruct kids to "scream and make a scene if anyone tries to grab them or force them, in any way, to go with them."

Although this and other products use the term "Amber," they are not associated nor endorsed by the Department of Justice's AMBER Alert program. The Justice Department restricts the use of the Amber Alert logo but not the term "Amber."

Dedicated GPS Devices
There are several products on the market that use GPS to track your child along with a cellular device to notify parents where they are. With all such devices, their ability to determine a location is dependent on getting a GPS and cellular signal. GPS may not work indoors, around tall buildings, in forests, or other locations without a clear view of the sky. Cellular, as we all know, is also depended on location. Also, these devices work only as long as their battery does.

Amber Alert GPS 2G costs $379 product plus $9.99 to $19.99 a month for the service. It measures 1.77 inches long by 1.68 inches wide by .78 inches deep and is designed to fit into a backpack or be worn around a child's wrist. It can be programmed via the Web or a cell phone to send you text messages and e-mails with your child's location and a link to a map. You can also use it to create a "safe zone" or virtual boundary. If your kid wanders out of that zone you and up to four other trusted adults get a text messages and e-mail alerts every 5 minutes until you cancel. It also gives you a "bread crumb" location trail so you can see where your kid has been.

The device also has an SOS button that your kid can use to send a help message if they are in any kind of danger. A speed alert lets you know if the device is moving above a set speed. That way you can tell if your kid is in a car and, if so, how fast it's moving. The mere fact that your kid is moving faster than a walk could be a reason for concern if they're not supposed to be in a car or public transportation. Parents of teens can use it to make sure they're not speeding. There is even a temperature alert to help protect against young children being left in hot (or cold) cars. The device's battery is rated to last 12 hours between charges.

Another product is the WorldTracker Enduro. It measures 2.6 inches long by 1.4 inches wide by .79 inches deep and has a GPS receiver and a GSM SIM card to transmit its report to a Web site or send a notification to a parent by e-mail or text message. It too features real-time tracking and allows a parent to be alerted if a child leaves a virtual safe zone. It also tracks the speed and altitude of the device, but a feature that will alert a parent if a child exceeds a certain speed is "in the works," according to a company spokesperson. The Enduro has a rechargeable lithium ion battery that, according to the company, tracks for up to a week on a single charge. It costs $295 plus $49.99 a month for service that includes unlimited tracking. You can also use your own T-mobile or AT&T SIM card and pay $20 a month for the service in addition to your cellular plan.

Other companies in this space include Whereify Wireless, U.K.-based lok8u, and TrackMyKids.

Cell phone services
All cell phones sold in North America have GPS tracking capability so that 911 operators can locate users in an emergency. That same technology can also be used to track the location of the phone either as a child locator or a friend tracker.

AT&T, Sprint, and Verizon offer add-on services that allow parents to track the location of their kids cell phone. AT&T FamilyMap and Verizon Chaperone cost $9.99 a month, while Sprint Family Locator is $5 a month. All of these services allow you to see real-time location on a map and get automatic location alerts.

With all these devices your kid, of course, needs to have the cell phone with him or her and turned on.

In addition to what's offered by the phone carriers, there are some third-party services that can track and report location. These include Loopt, Glympse, and Google's free Latitude service. None of these services is marketed as child locators. Latitude only gives an approximate location on a map and doesn't attempt to pinpoint a street address. It would be better than nothing in an emergency but not nearly as precise as the dedicated child locator services. Glympse, which works with Android phones and soon iPhones and BlackBerrys, is a permission-based system that allows the phone user to send an e-mail or text message that gives someone the ability to track them for a specific period of time--never more than four consecutive hours. Once you get a "Gympse" you can see that person's location on a map and, if on the move, you can see their path and their speed. It's a great way to track teens who would have to agree to be tracked such as a condition for borrowing the car, but it's not really well suited for tracking young children.

Loopt is designed to help friends locate each other, but it could be used to locate a child.